random.c

/* random.c
 *
 * Copyright (C) 2006-2026 wolfSSL Inc.
 *
 * This file is part of wolfSSL.
 *
 * wolfSSL is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * wolfSSL is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
 */

/*

DESCRIPTION
This library contains implementation for the random number generator.

*/

/*
 * Random Number Generator Build Options:
 *
 * Core RNG:
 * WC_NO_RNG:               Disable RNG support entirely         default: off
 * HAVE_HASHDRBG:            Enable Hash-based DRBG (SP 800-90A) default: on
 * WC_RNG_BLOCKING:          Make RNG operations blocking         default: off
 * WC_VERBOSE_RNG:           Enable verbose RNG debug output      default: off
 * WC_RNG_SEED_CB:           Use custom seed callback function    default: off
 * WC_RNG_BANK_SUPPORT:      Enable RNG bank (pre-generated)     default: off
 *                            random data support
 * WOLFSSL_RNG_USE_FULL_SEED: Use full-length seed for DRBG      default: off
 * WOLFSSL_GENSEED_FORTEST:  Use deterministic seed for testing   default: off
 *                            WARNING: not for production use
 * WOLFSSL_KEEP_RNG_SEED_FD_OPEN: Keep /dev/random fd open       default: off
 *                            between seed operations
 *
 * Custom RNG Sources:
 * CUSTOM_RAND_GENERATE:     Custom random word generator func    default: off
 * CUSTOM_RAND_GENERATE_BLOCK: Custom block random generator      default: off
 * CUSTOM_RAND_GENERATE_SEED: Custom seed generator function      default: off
 * CUSTOM_RAND_GENERATE_SEED_OS: Custom OS-level seed generator   default: off
 *
 * Entropy Sources:
 * HAVE_ENTROPY_MEMUSE:      Enable memory-use based entropy      default: off
 *                            source for DRBG seeding
 * ENTROPY_MEMUSE_FORCE_FAILURE: Force entropy failure (testing)  default: off
 * HAVE_GETRANDOM:           Use Linux getrandom() syscall        default: auto
 * WOLFSSL_GETRANDOM:        Use getrandom() for seed source      default: auto
 * FORCE_FAILURE_GETRANDOM:  Force getrandom failure (testing)    default: off
 * NO_DEV_RANDOM:            Don't use /dev/random for seeding    default: off
 * NO_DEV_URANDOM:           Don't use /dev/urandom for seeding   default: off
 * HAVE_INTEL_RDRAND:        Use Intel RDRAND instruction         default: off
 * HAVE_INTEL_RDSEED:        Use Intel RDSEED instruction         default: off
 * HAVE_AMD_RDSEED:          Use AMD RDSEED instruction           default: off
 * IDIRECT_DEV_RANDOM:       iDirect custom /dev/random path      default: off
 * WIN_REUSE_CRYPT_HANDLE:   Reuse Windows CryptContext handle    default: off
 *
 * Entropy Tuning (for HAVE_ENTROPY_MEMUSE):
 * ENTROPY_NUM_UPDATE:       Number of updates per sample         default: 18
 *                            More updates = better entropy but slower
 * ENTROPY_NUM_UPDATES_BITS: Bits to represent ENTROPY_NUM_UPDATE default: 5
 *                            = upper(log2(ENTROPY_NUM_UPDATE))
 * ENTROPY_NUM_WORDS_BITS:   State size as 2^N entries            default: 14
 *                            Range: 8-30. Base on cache sizes.
 *                            Larger = more cache misses = better entropy
 *                            but more static memory usage.
 *
 * DRBG Health Tests:
 * WC_RNG_SEED_APT_CUTOFF:  Adaptive proportion test cutoff      default: auto
 * WC_RNG_SEED_APT_WINDOW:  Adaptive proportion test window size  default: auto
 * WC_RNG_SEED_RCT_CUTOFF:  Repetition count test cutoff         default: auto
 *
 * Hardware RNG:
 * STM32_RNG:                STM32 hardware RNG                   default: off
 * STM32_NUTTX_RNG:          STM32 RNG via NuttX                  default: off
 * WOLFSSL_STM32F427_RNG:    STM32F427 hardware RNG               default: off
 * WOLFSSL_STM32_RNG_NOLIB:  STM32 RNG without HAL library        default: off
 * WOLFSSL_PIC32MZ_RNG:      PIC32MZ hardware RNG                 default: off
 * FREESCALE_RNGA:           Freescale RNGA                       default: off
 * FREESCALE_K70_RNGA:       Freescale K70 RNGA                   default: off
 * FREESCALE_RNGB:           Freescale RNGB                       default: off
 * FREESCALE_KSDK_2_0_RNGA:  Freescale KSDK 2.0 RNGA              default: off
 * FREESCALE_KSDK_2_0_TRNG:  Freescale KSDK 2.0 TRNG              default: off
 * MAX3266X_RNG:             MAX3266X hardware RNG                default: off
 * QAT_ENABLE_RNG:           Intel QAT hardware RNG               default: off
 * WOLFSSL_ATECC_RNG:        ATECC508/608 hardware RNG            default: off
 * WOLFSSL_SILABS_TRNG:      Silicon Labs TRNG                    default: off
 * WOLFSSL_SCE_NO_TRNG:      Disable Renesas SCE TRNG             default: off
 * WOLFSSL_SCE_TRNG_HANDLE:  Renesas SCE TRNG handle              default: off
 * WOLFSSL_SE050_NO_TRNG:    Disable SE050 TRNG                   default: off
 * WOLFSSL_PSA_NO_RNG:       Disable PSA RNG                      default: off
 * HAVE_IOTSAFE_HWRNG:       IoT-Safe hardware RNG                default: off
 * WOLFSSL_XILINX_CRYPT_VERSAL: Xilinx Versal crypto RNG          default: off
 * WOLFSSL_VA416X0_TRNG:     Vorago VA416x0 hardware TRNG         default: off
 *                           (seeds Hash-DRBG; needs the VA416xx
 *                           SDK header va416xx.h on the include
 *                           path). See the wc_GenerateSeed()
 *                           implementation below for SDK API and
 *                           tuning details.
 */

#include <wolfssl/wolfcrypt/libwolfssl_sources.h>

/* on HPUX 11 you may need to install /dev/random see
   http://h20293.www2.hp.com/portal/swdepot/displayProductInfo.do?productNumber=KRNG11I

*/
#if defined(ESP_IDF_VERSION_MAJOR) && ESP_IDF_VERSION_MAJOR >= 5
    #include <esp_random.h>
#endif

#if defined(HAVE_FIPS) && \
    defined(HAVE_FIPS_VERSION) && (HAVE_FIPS_VERSION >= 2)

    /* set NO_WRAPPERS before headers, use direct internal f()s not wrappers */
    #define FIPS_NO_WRAPPERS

    #ifdef USE_WINDOWS_API
        #pragma code_seg(".fipsA$i")
        #pragma const_seg(".fipsB$i")
    #endif
#endif


#include <wolfssl/wolfcrypt/random.h>
#ifdef WC_RNG_BANK_SUPPORT
    #include <wolfssl/wolfcrypt/rng_bank.h>
#endif
#include <wolfssl/wolfcrypt/cpuid.h>

#ifndef WC_NO_RNG /* if not FIPS and RNG is disabled then do not compile */

#ifndef NO_SHA256
    #include <wolfssl/wolfcrypt/sha256.h>
#endif
#ifdef WOLFSSL_DRBG_SHA512
    #include <wolfssl/wolfcrypt/sha512.h>
#endif

#ifdef WOLF_CRYPTO_CB
    #include <wolfssl/wolfcrypt/cryptocb.h>
#endif

#ifdef NO_INLINE
    #include <wolfssl/wolfcrypt/misc.h>
#else
    #define WOLFSSL_MISC_INCLUDED
    #include <wolfcrypt/src/misc.c>
#endif

#if defined(WOLFSSL_SGX)
    #include <sgx_trts.h>
#elif defined(USE_WINDOWS_API)
    #ifndef _WIN32_WINNT
        #define _WIN32_WINNT 0x0400
    #endif
    #define _WINSOCKAPI_ /* block inclusion of winsock.h header file */
    #include <windows.h>
    #include <wincrypt.h>
    #undef _WINSOCKAPI_ /* undefine it for MINGW winsock2.h header file */
#elif defined(HAVE_WNR)
    #include <wnr.h>
    wolfSSL_Mutex wnr_mutex WOLFSSL_MUTEX_INITIALIZER_CLAUSE(wnr_mutex);    /* global netRandom mutex */
    int wnr_timeout     = 0;    /* entropy timeout, milliseconds */
    #ifndef WOLFSSL_MUTEX_INITIALIZER
    int wnr_mutex_inited = 0;   /* flag for mutex init */
    #endif
    int wnr_inited = 0;    /* flag for whether wc_InitNetRandom() has been called */
    wnr_context*  wnr_ctx;      /* global netRandom context */
#elif defined(FREESCALE_KSDK_2_0_TRNG)
    #include "fsl_trng.h"
#elif defined(FREESCALE_KSDK_2_0_RNGA)
    #include "fsl_rnga.h"
#elif defined(WOLFSSL_WICED)
    #include "wiced_crypto.h"
#elif defined(WOLFSSL_NETBURNER)
    #include <predef.h>
    #include <basictypes.h>
    #include <random.h>
#elif defined(WOLFSSL_XILINX_CRYPT_VERSAL)
    #include "wolfssl/wolfcrypt/port/xilinx/xil-versal-trng.h"
#elif defined(WOLFSSL_RPIPICO)
    #include "wolfssl/wolfcrypt/port/rpi_pico/pico.h"
#elif defined(NO_DEV_RANDOM)
#elif defined(CUSTOM_RAND_GENERATE)
#elif defined(CUSTOM_RAND_GENERATE_BLOCK)
#elif defined(CUSTOM_RAND_GENERATE_SEED)
#elif defined(WOLFSSL_GENSEED_FORTEST)
#elif defined(WOLFSSL_MDK_ARM)
#elif defined(WOLFSSL_IAR_ARM)
#elif defined(WOLFSSL_ROWLEY_ARM)
#elif defined(WOLFSSL_EMBOS)
#elif defined(WOLFSSL_DEOS)
#elif defined(MICRIUM)
#elif defined(WOLFSSL_NUCLEUS)
#elif defined(WOLFSSL_PB)
#elif defined(WOLFSSL_ZEPHYR)
#elif defined(WOLFSSL_TELIT_M2MB)
#elif defined(WOLFSSL_RENESAS_TSIP)
    /* for wc_tsip_GenerateRandBlock */
    #include "wolfssl/wolfcrypt/port/Renesas/renesas_tsip_internal.h"
#elif defined(WOLFSSL_SCE) && !defined(WOLFSSL_SCE_NO_TRNG)
#elif defined(WOLFSSL_IMXRT1170_CAAM)
#elif defined(CY_USING_HAL) && defined(COMPONENT_WOLFSSL)
    #include "cyhal_trng.h" /* Infineon/Cypress HAL RNG implementation */
#elif defined(WOLFSSL_MAX3266X) || defined(WOLFSSL_MAX3266X_OLD)
    #include "wolfssl/wolfcrypt/port/maxim/max3266x.h"
#else
    #include <errno.h>
    #if defined(WOLFSSL_GETRANDOM) || defined(HAVE_GETRANDOM)
        #include <sys/random.h>
    #endif
    /* include headers that may be needed to get good seed */
    #include <fcntl.h>
    #ifndef EBSNET
        #include <unistd.h>
    #endif
#endif

#if defined(WOLFSSL_SILABS_SE_ACCEL)
#include <wolfssl/wolfcrypt/port/silabs/silabs_random.h>
#endif

#if defined(WOLFSSL_IOTSAFE) && defined(HAVE_IOTSAFE_HWRNG)
#include <wolfssl/wolfcrypt/port/iotsafe/iotsafe.h>
#endif

#if defined(WOLFSSL_HAVE_PSA) && !defined(WOLFSSL_PSA_NO_RNG)
#include <wolfssl/wolfcrypt/port/psa/psa.h>
#endif

#if FIPS_VERSION3_GE(6,0,0)
    const unsigned int wolfCrypt_FIPS_drbg_ro_sanity[2] =
                                                     { 0x1a2b3c4d, 0x00000011 };
    int wolfCrypt_FIPS_DRBG_sanity(void)
    {
        return 0;
    }
#endif

#if defined(HAVE_INTEL_RDRAND) || defined(HAVE_INTEL_RDSEED) || \
    defined(HAVE_AMD_RDSEED)
    static cpuid_flags_t intel_flags = WC_CPUID_INITIALIZER;
    static void wc_InitRng_IntelRD(void)
    {
        cpuid_get_flags_ex(&intel_flags);
    }
    #if defined(HAVE_INTEL_RDSEED) || defined(HAVE_AMD_RDSEED)
    static int wc_GenerateSeed_IntelRD(OS_Seed* os, byte* output, word32 sz);
    #endif
    #ifdef HAVE_INTEL_RDRAND
    static int wc_GenerateRand_IntelRD(OS_Seed* os, byte* output, word32 sz);
    #endif

#ifdef USE_WINDOWS_API
    #define USE_INTEL_INTRINSICS
#elif !defined __GNUC__ || defined __clang__ || __GNUC__ > 4
    #define USE_INTEL_INTRINSICS
#else
    #undef USE_INTEL_INTRINSICS
#endif

#ifdef USE_INTEL_INTRINSICS
    #include <immintrin.h>
    /* Before clang 7 or GCC 9, immintrin.h did not define _rdseed64_step() */
    #ifndef HAVE_INTEL_RDSEED
    #elif defined __clang__ && __clang_major__ > 6
    #elif !defined __GNUC__
    #elif __GNUC__ > 8
    #else
        #ifndef __clang__
            #pragma GCC push_options
            #pragma GCC target("rdseed")
        #else
            #define __RDSEED__
        #endif
        #include <x86intrin.h>
        #ifndef __clang__
            #pragma GCC pop_options
        #endif
    #endif
#endif /* USE_WINDOWS_API */
#endif

/* Start NIST DRBG code */
#ifdef HAVE_HASHDRBG

#define OUTPUT_BLOCK_LEN  (WC_SHA256_DIGEST_SIZE)
#define MAX_REQUEST_LEN   (0x10000)

#ifdef WC_RNG_SEED_CB

#ifndef HAVE_FIPS
static wc_RngSeed_Cb seedCb = wc_GenerateSeed;
#else
static wc_RngSeed_Cb seedCb = NULL;
#endif

int wc_SetSeed_Cb(wc_RngSeed_Cb cb)
{
    seedCb = cb;
    return 0;
}

#endif


/* Internal return codes */
#define DRBG_SUCCESS      0
#define DRBG_FAILURE      1
#define DRBG_NEED_RESEED  2
#define DRBG_CONT_FAILURE 3
#define DRBG_NO_SEED_CB   4

/* RNG health states */
#define DRBG_NOT_INIT     WC_DRBG_NOT_INIT
#define DRBG_OK           WC_DRBG_OK
#define DRBG_FAILED       WC_DRBG_FAILED
#define DRBG_CONT_FAILED  WC_DRBG_CONT_FAILED

#define SEED_SZ           WC_DRBG_SEED_SZ
#define MAX_SEED_SZ       WC_DRBG_MAX_SEED_SZ

/* Verify max gen block len */
#if RNG_MAX_BLOCK_LEN > MAX_REQUEST_LEN
    #error RNG_MAX_BLOCK_LEN is larger than NIST DBRG max request length
#endif

enum {
    drbgInitC     = 0,
    drbgReseed    = 1,
    drbgGenerateW = 2,
    drbgGenerateH = 3,
    drbgInitV     = 4
};

#ifndef NO_SHA256
typedef struct DRBG_internal DRBG_internal;
#endif

#ifdef WOLFSSL_DRBG_SHA512
typedef struct DRBG_SHA512_internal DRBG_SHA512_internal;

static int Hash512_DRBG_Reseed(DRBG_SHA512_internal* drbg, const byte* seed,
                               word32 seedSz,
                               const byte* additional, word32 additionalSz);
static int Hash512_DRBG_Generate(DRBG_SHA512_internal* drbg, byte* out,
                                 word32 outSz,
                                 const byte* additional, word32 additionalSz);
static int Hash512_DRBG_Instantiate(DRBG_SHA512_internal* drbg,
                                    const byte* seed, word32 seedSz,
                                    const byte* nonce, word32 nonceSz,
                                    const byte* perso, word32 persoSz,
                                    void* heap, int devId);
static int Hash512_DRBG_Uninstantiate(DRBG_SHA512_internal* drbg);
#endif

/* Runtime DRBG disable state.
 * These flags control which DRBG type is used for new WC_RNG instances and
 * may be toggled at runtime (e.g. NSA Suite 2.0 threads disable SHA-256).
 * A mutex protects the check-then-set in disable functions so concurrent
 * calls cannot bypass the mutual-exclusion guard and disable both DRBG types.
 * _InitRng also holds the mutex while reading the flags to get a consistent
 * snapshot, and returns BAD_STATE_E if both are somehow disabled. */
#ifndef NO_SHA256
#ifdef WOLFSSL_NO_SHA256_DRBG
static int sha256DrbgDisabled = 1;
#else
static int sha256DrbgDisabled = 0;
#endif
#endif
#ifdef WOLFSSL_DRBG_SHA512
static int sha512DrbgDisabled = 0;
#endif

#ifndef SINGLE_THREADED
static wolfSSL_Mutex drbgStateMutex
    WOLFSSL_MUTEX_INITIALIZER_CLAUSE(drbgStateMutex);
#ifndef WOLFSSL_MUTEX_INITIALIZER
static int drbgStateMutex_inited = 0;
#endif
#endif /* !SINGLE_THREADED */

int wc_DrbgState_MutexInit(void)
{
#ifndef SINGLE_THREADED
#ifndef WOLFSSL_MUTEX_INITIALIZER
    if (!drbgStateMutex_inited) {
        int ret = wc_InitMutex(&drbgStateMutex);
        if (ret != 0)
            return ret;
        drbgStateMutex_inited = 1;
    }
#endif
#endif
    return 0;
}

int wc_DrbgState_MutexFree(void)
{
#ifndef SINGLE_THREADED
#ifndef WOLFSSL_MUTEX_INITIALIZER
    if (drbgStateMutex_inited) {
        int ret = wc_FreeMutex(&drbgStateMutex);
        drbgStateMutex_inited = 0;
        return ret;
    }
#endif
#endif
    return 0;
}

static int LockDrbgState(void)
{
#ifndef SINGLE_THREADED
    return wc_LockMutex(&drbgStateMutex);
#else
    return 0;
#endif
}

static int UnlockDrbgState(void)
{
#ifndef SINGLE_THREADED
    return wc_UnLockMutex(&drbgStateMutex);
#else
    return 0;
#endif
}

static int wc_RNG_HealthTestLocal(WC_RNG* rng, int reseed, void* heap,
                                  int devId);

#ifdef WOLFSSL_DRBG_SHA512
static int wc_RNG_HealthTest_SHA512_ex_internal(DRBG_SHA512_internal* drbg,
                                  int reseed, const byte* nonce, word32 nonceSz,
                                  const byte* perso, word32 persoSz,
                                  const byte* seedA, word32 seedASz,
                                  const byte* seedB, word32 seedBSz,
                                  const byte* additionalA, word32 additionalASz,
                                  const byte* additionalB, word32 additionalBSz,
                                  byte* output, word32 outputSz,
                                  void* heap, int devId);
#endif

/* The SHA-256 Hash_DRBG core (Hash_df, Hash_DRBG_*) operates on
 * DRBG_internal, which random.h defines only when SHA-256 is compiled in.
 * Wrap the whole block so a NO_SHA256 + WOLFSSL_DRBG_SHA512 build (the
 * SHA-512-only DRBG configuration) still compiles. The SHA-512 DRBG core
 * lives below in its own #ifdef WOLFSSL_DRBG_SHA512 section. */
#ifndef NO_SHA256

/* Hash Derivation Function */
/* Returns: DRBG_SUCCESS or DRBG_FAILURE */
static int Hash_df(DRBG_internal* drbg, byte* out, word32 outSz, byte type,
                                                  const byte* inA, word32 inASz,
                                                  const byte* inB, word32 inBSz,
                                                  const byte* inC, word32 inCSz)
{
    int ret = DRBG_FAILURE;
    byte ctr;
    word32 i;
    word32 len;
    word32 bits = (outSz * 8); /* reverse byte order */
#ifdef WOLFSSL_SMALL_STACK_CACHE
    wc_Sha256* sha = &drbg->sha256;
#else
    wc_Sha256 sha[1];
#endif
#if defined(WOLFSSL_SMALL_STACK_CACHE)
    byte* digest = drbg->digest_scratch;
#elif defined(WOLFSSL_SMALL_STACK)
    byte* digest;
#else
    byte digest[WC_SHA256_DIGEST_SIZE];
#endif

    if (drbg == NULL) {
        return DRBG_FAILURE;
    }

#if defined(WOLFSSL_SMALL_STACK) && !defined(WOLFSSL_SMALL_STACK_CACHE)
    digest = (byte*)XMALLOC(WC_SHA256_DIGEST_SIZE, drbg->heap,
        DYNAMIC_TYPE_DIGEST);
    if (digest == NULL)
        return DRBG_FAILURE;
#endif

#ifdef LITTLE_ENDIAN_ORDER
    bits = ByteReverseWord32(bits);
#endif
    len = (outSz / OUTPUT_BLOCK_LEN)
        + ((outSz % OUTPUT_BLOCK_LEN) ? 1 : 0);

    ctr = 1;
    for (i = 0; i < len; i++) {
#ifndef WOLFSSL_SMALL_STACK_CACHE
    #if defined(WOLFSSL_ASYNC_CRYPT) || defined(WOLF_CRYPTO_CB)
        ret = wc_InitSha256_ex(sha, drbg->heap, drbg->devId);
    #else
        ret = wc_InitSha256(sha);
    #endif
        if (ret != 0)
            break;
#endif
        ret = wc_Sha256Update(sha, &ctr, sizeof(ctr));
        if (ret == 0) {
            ctr++;
            ret = wc_Sha256Update(sha, (byte*)&bits, sizeof(bits));
        }

        if (ret == 0) {
            /* churning V is the only string that doesn't have the type added */
            if (type != drbgInitV)
                ret = wc_Sha256Update(sha, &type, sizeof(type));
        }
        if (ret == 0)
            ret = wc_Sha256Update(sha, inA, inASz);
        if (ret == 0) {
            if (inB != NULL && inBSz > 0)
                ret = wc_Sha256Update(sha, inB, inBSz);
        }
        if (ret == 0) {
            if (inC != NULL && inCSz > 0)
                ret = wc_Sha256Update(sha, inC, inCSz);
        }
        if (ret == 0)
            ret = wc_Sha256Final(sha, digest);

#ifndef WOLFSSL_SMALL_STACK_CACHE
        wc_Sha256Free(sha);
#endif
        if (ret == 0) {
            if (outSz > OUTPUT_BLOCK_LEN) {
                XMEMCPY(out, digest, OUTPUT_BLOCK_LEN);
                outSz -= OUTPUT_BLOCK_LEN;
                out += OUTPUT_BLOCK_LEN;
            }
            else {
                XMEMCPY(out, digest, outSz);
            }
        }
    }

    ForceZero(digest, WC_SHA256_DIGEST_SIZE);

#if defined(WOLFSSL_SMALL_STACK) && !defined(WOLFSSL_SMALL_STACK_CACHE)
    XFREE(digest, drbg->heap, DYNAMIC_TYPE_DIGEST);
#endif

#ifdef WC_VERBOSE_RNG
    if (ret != 0)
        WOLFSSL_DEBUG_PRINTF("ERROR: %s failed with err = %d", __FUNCTION__,
                             ret);
#endif

    return (ret == 0) ? DRBG_SUCCESS : DRBG_FAILURE;
}

/* Returns: DRBG_SUCCESS or DRBG_FAILURE */
static int Hash_DRBG_Reseed(DRBG_internal* drbg, const byte* seed, word32 seedSz,
                            const byte* additional, word32 additionalSz)
{
    int ret;
    WC_DECLARE_VAR(newV, byte, DRBG_SEED_LEN, 0);

    if (drbg == NULL) {
        return DRBG_FAILURE;
    }

#ifdef WOLFSSL_SMALL_STACK_CACHE
    newV = drbg->seed_scratch;
#else
    WC_ALLOC_VAR_EX(newV, byte, DRBG_SEED_LEN, drbg->heap,
        DYNAMIC_TYPE_TMP_BUFFER, return MEMORY_E);
#endif
    XMEMSET(newV, 0, DRBG_SEED_LEN);

    ret = Hash_df(drbg, newV, DRBG_SEED_LEN, drbgReseed,
                drbg->V, sizeof(drbg->V), seed, seedSz,
                additional, additionalSz);
    if (ret == DRBG_SUCCESS) {
        XMEMCPY(drbg->V, newV, sizeof(drbg->V));

        ret = Hash_df(drbg, drbg->C, sizeof(drbg->C), drbgInitC, drbg->V,
                                    sizeof(drbg->V), NULL, 0, NULL, 0);
    }
    if (ret == DRBG_SUCCESS) {
        drbg->reseedCtr = 1;
    }

    ForceZero(newV, DRBG_SEED_LEN);

#ifndef WOLFSSL_SMALL_STACK_CACHE
    WC_FREE_VAR_EX(newV, drbg->heap, DYNAMIC_TYPE_TMP_BUFFER);
#endif

    #ifdef WC_VERBOSE_RNG
    if (ret != 0)
        WOLFSSL_DEBUG_PRINTF("ERROR: Hash_DRBG_Reseed failed with err %d.",
                             ret);
    #endif

    return ret;
}

#endif /* !NO_SHA256 - close before wc_RNG_DRBG_Reseed (dual-DRBG-aware)
        *              and array_add_one (shared utility) which both must
        *              remain available to SHA-512-only builds */

/* Returns: DRBG_SUCCESS and DRBG_FAILURE or BAD_FUNC_ARG on fail */
int wc_RNG_DRBG_Reseed(WC_RNG* rng, const byte* seed, word32 seedSz)
{
    if (rng == NULL || seed == NULL) {
        return BAD_FUNC_ARG;
    }

#ifndef NO_SHA256
    if (rng->drbgType == WC_DRBG_SHA256) {
        if (rng->drbg == NULL) {
        #if defined(HAVE_INTEL_RDSEED) || defined(HAVE_INTEL_RDRAND)
            if (IS_INTEL_RDRAND(intel_flags)) {
                /* using RDRAND not DRBG, so return success */
                return 0;
            }
        #endif
            return BAD_FUNC_ARG;
        }
        return Hash_DRBG_Reseed((DRBG_internal *)rng->drbg, seed, seedSz,
                                NULL, 0);
    }
#endif
#ifdef WOLFSSL_DRBG_SHA512
    if (rng->drbgType == WC_DRBG_SHA512) {
        if (rng->drbg512 == NULL) {
        #if defined(HAVE_INTEL_RDSEED) || defined(HAVE_INTEL_RDRAND)
            if (IS_INTEL_RDRAND(intel_flags)) {
                /* using RDRAND not DRBG, so return success */
                return 0;
            }
        #endif
            return BAD_FUNC_ARG;
        }
        return Hash512_DRBG_Reseed((DRBG_SHA512_internal *)rng->drbg512,
                                   seed, seedSz, NULL, 0);
    }
#endif

    /* No DRBG type matched; if using RDRAND, that's OK */
#if defined(HAVE_INTEL_RDSEED) || defined(HAVE_INTEL_RDRAND)
    if (IS_INTEL_RDRAND(intel_flags)) {
        return 0;
    }
#endif

    return BAD_FUNC_ARG;
}

/* Generic byte-array helper -- shared by both SHA-256 and SHA-512 DRBG
 * cores. Lives outside the NO_SHA256 guard so SHA-512-only builds
 * still link. */
static WC_INLINE void array_add_one(byte* data, word32 dataSz)
{
    int i;
    for (i = (int)dataSz - 1; i >= 0; i--) {
        data[i]++;
        if (data[i] != 0) break;
    }
}

#ifndef NO_SHA256 /* re-open SHA-256 Hash_DRBG core */

/* Returns: DRBG_SUCCESS or DRBG_FAILURE */
static int Hash_gen(DRBG_internal* drbg, byte* out, word32 outSz, const byte* V)
{
    int ret = DRBG_FAILURE;
    word32 i;
    word32 len;
#if defined(WOLFSSL_SMALL_STACK_CACHE)
    wc_Sha256* sha = &drbg->sha256;
    byte* data = drbg->seed_scratch;
    byte* digest = drbg->digest_scratch;
#elif defined(WOLFSSL_SMALL_STACK)
    wc_Sha256 sha[1];
    byte* data = NULL;
    byte* digest = NULL;
#else
    wc_Sha256 sha[1];
    byte data[DRBG_SEED_LEN];
    byte digest[WC_SHA256_DIGEST_SIZE];
#endif

    if (drbg == NULL) {
        return DRBG_FAILURE;
    }

#if defined(WOLFSSL_SMALL_STACK) && !defined(WOLFSSL_SMALL_STACK_CACHE)
    data = (byte*)XMALLOC(DRBG_SEED_LEN, drbg->heap, DYNAMIC_TYPE_TMP_BUFFER);
    digest = (byte*)XMALLOC(WC_SHA256_DIGEST_SIZE, drbg->heap,
        DYNAMIC_TYPE_DIGEST);
    if (data == NULL || digest == NULL) {
        XFREE(digest, drbg->heap, DYNAMIC_TYPE_DIGEST);
        XFREE(data, drbg->heap, DYNAMIC_TYPE_TMP_BUFFER);
        return DRBG_FAILURE;
    }
#endif

    /* Special case: outSz is 0 and out is NULL. wc_Generate a block to save for
     * the continuous test. */

    if (outSz == 0) {
        outSz = 1;
    }

    len = (outSz / OUTPUT_BLOCK_LEN) + ((outSz % OUTPUT_BLOCK_LEN) ? 1 : 0);

    XMEMCPY(data, V, DRBG_SEED_LEN);
    for (i = 0; i < len; i++) {
#ifndef WOLFSSL_SMALL_STACK_CACHE
    #if defined(WOLFSSL_ASYNC_CRYPT) || defined(WOLF_CRYPTO_CB)
        ret = wc_InitSha256_ex(sha, drbg->heap, drbg->devId);
    #else
        ret = wc_InitSha256(sha);
    #endif
        if (ret == 0)
#endif
            ret = wc_Sha256Update(sha, data, DRBG_SEED_LEN);
        if (ret == 0)
            ret = wc_Sha256Final(sha, digest);
#ifndef WOLFSSL_SMALL_STACK_CACHE
        wc_Sha256Free(sha);
#endif

        if (ret == 0) {
            if (out != NULL && outSz != 0) {
                if (outSz >= OUTPUT_BLOCK_LEN) {
                    XMEMCPY(out, digest, OUTPUT_BLOCK_LEN);
                    outSz -= OUTPUT_BLOCK_LEN;
                    out += OUTPUT_BLOCK_LEN;
                    array_add_one(data, DRBG_SEED_LEN);
                }
                else {
                    XMEMCPY(out, digest, outSz);
                    outSz = 0;
                }
            }
        }
        else {
            /* wc_Sha256Update or wc_Sha256Final returned error */
            break;
        }
    }
    ForceZero(data, DRBG_SEED_LEN);

#ifndef WOLFSSL_SMALL_STACK_CACHE
    WC_FREE_VAR_EX(digest, drbg->heap, DYNAMIC_TYPE_DIGEST);
    WC_FREE_VAR_EX(data, drbg->heap, DYNAMIC_TYPE_TMP_BUFFER);
#endif

    #ifdef WC_VERBOSE_RNG
    if ((ret != DRBG_SUCCESS) && (ret != DRBG_FAILURE)) {
        /* Note, if we're just going to return DRBG_FAILURE to the caller, then
         * there's no point printing it out here because (1) the lower-level
         * code that was remapped to DRBG_FAILURE already got printed before the
         * remapping, so a DRBG_FAILURE message would just be spamming the log,
         * and (2) the caller will actually see the DRBG_FAILURE code, and is
         * free to (and probably will) log it itself.
         */
        WOLFSSL_DEBUG_PRINTF("ERROR: Hash_gen failed with err %d.", ret);
    }
    #endif

    return (ret == 0) ? DRBG_SUCCESS : DRBG_FAILURE;
}

#endif /* !NO_SHA256 - close to expose array_add to SHA-512 below */

/* Generic multi-byte add. Shared by SHA-256 and SHA-512 DRBG cores;
 * lives outside the NO_SHA256 guard so SHA-512-only builds still link. */
static WC_INLINE void array_add(byte* d, word32 dLen, const byte* s, word32 sLen)
{
    if (dLen > 0 && sLen > 0 && dLen >= sLen) {
        int sIdx, dIdx;
        word16 carry = 0;

        dIdx = (int)dLen - 1;
        for (sIdx = (int)sLen - 1; sIdx >= 0; sIdx--) {
            carry = (word16)(carry + d[dIdx] + s[sIdx]);
            d[dIdx] = (byte)carry;
            carry >>= 8;
            dIdx--;
        }

        for (; dIdx >= 0; dIdx--) {
            carry = (word16)(carry + d[dIdx]);
            d[dIdx] = (byte)carry;
            carry >>= 8;
        }
    }
}

#ifndef NO_SHA256 /* re-open SHA-256 Hash_DRBG core */

/* Returns: DRBG_SUCCESS, DRBG_NEED_RESEED, or DRBG_FAILURE */
static int Hash_DRBG_Generate(DRBG_internal* drbg, byte* out, word32 outSz,
                              const byte* additional, word32 additionalSz)
{
    int ret;
#ifdef WOLFSSL_SMALL_STACK_CACHE
    wc_Sha256* sha = &drbg->sha256;
#else
    wc_Sha256 sha[1];
#endif
    byte type;
#ifdef WORD64_AVAILABLE
    word64 reseedCtr;
#else
    word32 reseedCtr;
#endif

    if (drbg == NULL) {
        return DRBG_FAILURE;
    }

    if (drbg->reseedCtr >= WC_RESEED_INTERVAL) {
    #if (defined(DEBUG_WOLFSSL) || defined(DEBUG_DRBG_RESEEDS)) && \
        defined(WOLFSSL_DEBUG_PRINTF)
        WOLFSSL_DEBUG_PRINTF("DRBG reseed triggered, reseedCtr == %lu",
                (unsigned long)drbg->reseedCtr);
    #endif
        return DRBG_NEED_RESEED;
    }
    else {
    #if defined(WOLFSSL_SMALL_STACK_CACHE)
        byte* digest = drbg->digest_scratch;
    #elif defined(WOLFSSL_SMALL_STACK)
        byte* digest = (byte*)XMALLOC(WC_SHA256_DIGEST_SIZE, drbg->heap,
            DYNAMIC_TYPE_DIGEST);
        if (digest == NULL)
            return DRBG_FAILURE;
    #else
        byte digest[WC_SHA256_DIGEST_SIZE];
    #endif

        type = drbgGenerateH;
        reseedCtr = drbg->reseedCtr;

        /* SP 800-90A 10.1.1.4 step 2: if additional_input != Null,
         * w = Hash(0x02 || V || additional_input), V = (V + w) mod 2^seedlen */
        if (additional != NULL && additionalSz > 0) {
            byte addType = drbgGenerateW;
#ifndef WOLFSSL_SMALL_STACK_CACHE
        #if defined(WOLFSSL_ASYNC_CRYPT) || defined(WOLF_CRYPTO_CB)
            ret = wc_InitSha256_ex(sha, drbg->heap, drbg->devId);
        #else
            ret = wc_InitSha256(sha);
        #endif
            if (ret != 0) {
            #if defined(WOLFSSL_SMALL_STACK) && !defined(WOLFSSL_SMALL_STACK_CACHE)
                XFREE(digest, drbg->heap, DYNAMIC_TYPE_DIGEST);
            #endif
                return DRBG_FAILURE;
            }
#else
            ret = 0;
#endif
            if (ret == 0)
                ret = wc_Sha256Update(sha, &addType, sizeof(addType));
            if (ret == 0)
                ret = wc_Sha256Update(sha, drbg->V, sizeof(drbg->V));
            if (ret == 0)
                ret = wc_Sha256Update(sha, additional, additionalSz);
            if (ret == 0)
                ret = wc_Sha256Final(sha, digest);
#ifndef WOLFSSL_SMALL_STACK_CACHE
            wc_Sha256Free(sha);
#endif
            if (ret == 0) {
                array_add(drbg->V, sizeof(drbg->V), digest,
                          WC_SHA256_DIGEST_SIZE);
            }
            else {
                ForceZero(digest, WC_SHA256_DIGEST_SIZE);
            #if defined(WOLFSSL_SMALL_STACK) && !defined(WOLFSSL_SMALL_STACK_CACHE)
                XFREE(digest, drbg->heap, DYNAMIC_TYPE_DIGEST);
            #endif
                return DRBG_FAILURE;
            }
        }

        ret = Hash_gen(drbg, out, outSz, drbg->V);
        if (ret == DRBG_SUCCESS) {
#ifndef WOLFSSL_SMALL_STACK_CACHE
        #if defined(WOLFSSL_ASYNC_CRYPT) || defined(WOLF_CRYPTO_CB)
            ret = wc_InitSha256_ex(sha, drbg->heap, drbg->devId);
        #else
            ret = wc_InitSha256(sha);
        #endif
            if (ret == 0)
#endif
                ret = wc_Sha256Update(sha, &type, sizeof(type));
            if (ret == 0)
                ret = wc_Sha256Update(sha, drbg->V, sizeof(drbg->V));
            if (ret == 0)
                ret = wc_Sha256Final(sha, digest);

#ifndef WOLFSSL_SMALL_STACK_CACHE
            wc_Sha256Free(sha);
#endif

            if (ret == 0) {
                array_add(drbg->V, sizeof(drbg->V), digest, WC_SHA256_DIGEST_SIZE);
                array_add(drbg->V, sizeof(drbg->V), drbg->C, sizeof(drbg->C));
            #ifdef LITTLE_ENDIAN_ORDER
                #ifdef WORD64_AVAILABLE
                reseedCtr = ByteReverseWord64(reseedCtr);
                #else
                reseedCtr = ByteReverseWord32(reseedCtr);
                #endif
            #endif
                array_add(drbg->V, sizeof(drbg->V),
                                          (byte*)&reseedCtr, sizeof(reseedCtr));
                ret = DRBG_SUCCESS;
            }
            drbg->reseedCtr++;
        }
        ForceZero(digest, WC_SHA256_DIGEST_SIZE);
    #if defined(WOLFSSL_SMALL_STACK) && !defined(WOLFSSL_SMALL_STACK_CACHE)
        XFREE(digest, drbg->heap, DYNAMIC_TYPE_DIGEST);
    #endif
    }

    #ifdef WC_VERBOSE_RNG
    if ((ret != DRBG_SUCCESS) && (ret != DRBG_FAILURE)) {
        /* see note above regarding log spam reduction */
        WOLFSSL_DEBUG_PRINTF("ERROR: Hash_DRBG_Generate failed with err %d.",
                             ret);
    }
    #endif

    return (ret == 0) ? DRBG_SUCCESS : DRBG_FAILURE;
}

/* Returns: DRBG_SUCCESS or DRBG_FAILURE */
static int Hash_DRBG_Init(DRBG_internal* drbg, const byte* seed, word32 seedSz,
                                             const byte* nonce, word32 nonceSz,
                                             const byte* perso, word32 persoSz)
{
    if (seed == NULL)
        return DRBG_FAILURE;

    if (Hash_df(drbg, drbg->V, sizeof(drbg->V), drbgInitV, seed, seedSz,
                                              nonce, nonceSz,
                                              perso, persoSz) == DRBG_SUCCESS &&
        Hash_df(drbg, drbg->C, sizeof(drbg->C), drbgInitC, drbg->V,
                                    sizeof(drbg->V), NULL, 0,
                                    NULL, 0) == DRBG_SUCCESS) {

        drbg->reseedCtr = 1;
        return DRBG_SUCCESS;
    }
    else {
        return DRBG_FAILURE;
    }
}

/* Returns: DRBG_SUCCESS or DRBG_FAILURE */
static int Hash_DRBG_Instantiate(DRBG_internal* drbg, const byte* seed,
                                 word32 seedSz, const byte* nonce,
                                 word32 nonceSz, const byte* perso,
                                 word32 persoSz, void* heap, int devId)
{
    int ret = DRBG_FAILURE;

    XMEMSET(drbg, 0, sizeof(DRBG_internal));
    drbg->heap = heap;
#if defined(WOLFSSL_ASYNC_CRYPT) || defined(WOLF_CRYPTO_CB)
    drbg->devId = devId;
#else
    (void)devId;
#endif

#ifdef WOLFSSL_SMALL_STACK_CACHE
    #if defined(WOLFSSL_ASYNC_CRYPT) || defined(WOLF_CRYPTO_CB)
        ret = wc_InitSha256_ex(&drbg->sha256, drbg->heap, drbg->devId);
    #else
        ret = wc_InitSha256(&drbg->sha256);
    #endif
    if (ret != 0)
        return ret;
#endif

    if (seed != NULL)
        ret = Hash_DRBG_Init(drbg, seed, seedSz, nonce, nonceSz,
                             perso, persoSz);
    return ret;
}

/* Returns: DRBG_SUCCESS or DRBG_FAILURE */
static int Hash_DRBG_Uninstantiate(DRBG_internal* drbg)
{
    word32 i;
    int    compareSum = 0;
    byte*  compareDrbg = (byte*)drbg;

#ifdef WOLFSSL_SMALL_STACK_CACHE
    wc_Sha256Free(&drbg->sha256);
#endif

    ForceZero(drbg, sizeof(DRBG_internal));

    for (i = 0; i < sizeof(DRBG_internal); i++) {
        compareSum |= compareDrbg[i] ^ 0;
    }

    return (compareSum == 0) ? DRBG_SUCCESS : DRBG_FAILURE;
}

#endif /* !NO_SHA256 - SHA-256 Hash_DRBG core block */

/* ====================================================================== */
/* SHA-512 Hash_DRBG (SP 800-90A Rev 1, Table 2)                          */
/*                                                                         */
/* Internal state (V, C): seedlen = 888 bits = 111 bytes each              */
/* Output block length:   512 bits = 64 bytes (WC_SHA512_DIGEST_SIZE)      */
/* Security strength:     256 bits                                         */
/*                                                                         */
/* NOTE: The raw entropy seed gathered at instantiation / reseed is        */
/* WC_DRBG_SEED_SZ (1024 bits in FIPS builds), NOT seedlen.  We overseed  */
/* to tolerate weak entropy sources.  Hash_df then compresses the seed     */
/* material down to the 888-bit V and derives C from V.  See random.h.    */
/* ====================================================================== */
#ifdef WOLFSSL_DRBG_SHA512

#define OUTPUT_BLOCK_LEN_SHA512  (WC_SHA512_DIGEST_SIZE)  /* 64 bytes */

/* Hash Derivation Function using SHA-512 */
/* Returns: DRBG_SUCCESS or DRBG_FAILURE */
static int Hash512_df(DRBG_SHA512_internal* drbg, byte* out, word32 outSz,
                      byte type,
                      const byte* inA, word32 inASz,
                      const byte* inB, word32 inBSz,
                      const byte* inC, word32 inCSz)
{
    int ret = DRBG_FAILURE;
    byte ctr;
    word32 i;
    word32 len;
    word32 bits = (outSz * 8);
#ifdef WOLFSSL_SMALL_STACK_CACHE
    wc_Sha512* sha = &drbg->sha512;
#else
    wc_Sha512 sha[1];
#endif
#if defined(WOLFSSL_SMALL_STACK_CACHE)
    byte* digest = drbg->digest_scratch;
#elif defined(WOLFSSL_SMALL_STACK)
    byte* digest;
#else
#if defined(__GNUC__) && !defined(__clang__) && defined(__AVX512F__)
    /* Use a jumbo alignment to work around a gcc compiler/optimizer bug that
     * assumes AVX512 alignment in an object sized correctly for AVX512 passed
     * to builtin memcpy(), which promptly crashes if not thus aligned.
     */
    byte digest[WC_SHA512_DIGEST_SIZE] WOLFSSL_ALIGN(WC_SHA512_DIGEST_SIZE);
#else
    byte digest[WC_SHA512_DIGEST_SIZE];
#endif
#endif

    if (drbg == NULL) {
        return DRBG_FAILURE;
    }

#if defined(WOLFSSL_SMALL_STACK) && !defined(WOLFSSL_SMALL_STACK_CACHE)
    digest = (byte*)XMALLOC(WC_SHA512_DIGEST_SIZE, drbg->heap,
        DYNAMIC_TYPE_DIGEST);
    if (digest == NULL)
        return DRBG_FAILURE;
#endif

#ifdef LITTLE_ENDIAN_ORDER
    bits = ByteReverseWord32(bits);
#endif
    len = (outSz / OUTPUT_BLOCK_LEN_SHA512)
        + ((outSz % OUTPUT_BLOCK_LEN_SHA512) ? 1 : 0);

    ctr = 1;
    for (i = 0; i < len; i++) {
#ifndef WOLFSSL_SMALL_STACK_CACHE
    #if defined(WOLFSSL_ASYNC_CRYPT) || defined(WOLF_CRYPTO_CB)
        ret = wc_InitSha512_ex(sha, drbg->heap, drbg->devId);
    #else
        ret = wc_InitSha512(sha);
    #endif
        if (ret != 0)
            break;
#endif
        ret = wc_Sha512Update(sha, &ctr, sizeof(ctr));
        if (ret == 0) {
            ctr++;
            ret = wc_Sha512Update(sha, (byte*)&bits, sizeof(bits));
        }

        if (ret == 0) {
            /* churning V is the only string that doesn't have the type added */
            if (type != drbgInitV)
                ret = wc_Sha512Update(sha, &type, sizeof(type));
        }
        if (ret == 0)
            ret = wc_Sha512Update(sha, inA, inASz);
        if (ret == 0) {
            if (inB != NULL && inBSz > 0)
                ret = wc_Sha512Update(sha, inB, inBSz);
        }
        if (ret == 0) {
            if (inC != NULL && inCSz > 0)
                ret = wc_Sha512Update(sha, inC, inCSz);
        }
        if (ret == 0)
            ret = wc_Sha512Final(sha, digest);

#ifndef WOLFSSL_SMALL_STACK_CACHE
        wc_Sha512Free(sha);
#endif
        if (ret == 0) {
            if (outSz > OUTPUT_BLOCK_LEN_SHA512) {
                XMEMCPY(out, digest, OUTPUT_BLOCK_LEN_SHA512);
                outSz -= OUTPUT_BLOCK_LEN_SHA512;
                out += OUTPUT_BLOCK_LEN_SHA512;
            }
            else {
                XMEMCPY(out, digest, outSz);
            }
        }
    }

    ForceZero(digest, WC_SHA512_DIGEST_SIZE);

#if defined(WOLFSSL_SMALL_STACK) && !defined(WOLFSSL_SMALL_STACK_CACHE)
    XFREE(digest, drbg->heap, DYNAMIC_TYPE_DIGEST);
#endif

#ifdef WC_VERBOSE_RNG
    if (ret != 0)
        WOLFSSL_DEBUG_PRINTF("ERROR: %s failed with err = %d", __FUNCTION__,
                             ret);
#endif

    return (ret == 0) ? DRBG_SUCCESS : DRBG_FAILURE;
}

/* Returns: DRBG_SUCCESS or DRBG_FAILURE */
static int Hash512_DRBG_Reseed(DRBG_SHA512_internal* drbg, const byte* seed,
                               word32 seedSz,
                               const byte* additional, word32 additionalSz)
{
    int ret;
    WC_DECLARE_VAR(newV, byte, DRBG_SHA512_SEED_LEN, 0);

    if (drbg == NULL) {
        return DRBG_FAILURE;
    }

#ifdef WOLFSSL_SMALL_STACK_CACHE
    newV = drbg->seed_scratch;
#else
    WC_ALLOC_VAR_EX(newV, byte, DRBG_SHA512_SEED_LEN, drbg->heap,
        DYNAMIC_TYPE_TMP_BUFFER, return MEMORY_E);
#endif
    XMEMSET(newV, 0, DRBG_SHA512_SEED_LEN);

    ret = Hash512_df(drbg, newV, DRBG_SHA512_SEED_LEN, drbgReseed,
                drbg->V, sizeof(drbg->V), seed, seedSz,
                additional, additionalSz);
    if (ret == DRBG_SUCCESS) {
        XMEMCPY(drbg->V, newV, sizeof(drbg->V));

        ret = Hash512_df(drbg, drbg->C, sizeof(drbg->C), drbgInitC, drbg->V,
                                    sizeof(drbg->V), NULL, 0,
                                    NULL, 0);
    }
    if (ret == DRBG_SUCCESS) {
        drbg->reseedCtr = 1;
    }

    ForceZero(newV, DRBG_SHA512_SEED_LEN);

#ifndef WOLFSSL_SMALL_STACK_CACHE
    WC_FREE_VAR_EX(newV, drbg->heap, DYNAMIC_TYPE_TMP_BUFFER);
#endif

    return ret;
}

/* Returns: DRBG_SUCCESS or DRBG_FAILURE */
static int Hash512_gen(DRBG_SHA512_internal* drbg, byte* out, word32 outSz,
                       const byte* V)
{
    int ret = DRBG_FAILURE;
    word32 i;
    word32 len;
#if defined(WOLFSSL_SMALL_STACK_CACHE)
    wc_Sha512* sha = &drbg->sha512;
    byte* data = drbg->seed_scratch;
    byte* digest = drbg->digest_scratch;
#elif defined(WOLFSSL_SMALL_STACK)
    wc_Sha512 sha[1];
    byte* data = NULL;
    byte* digest = NULL;
#else
    wc_Sha512 sha[1];
    byte data[DRBG_SHA512_SEED_LEN];
    byte digest[WC_SHA512_DIGEST_SIZE];
#endif

    if (drbg == NULL) {
        return DRBG_FAILURE;
    }

#if defined(WOLFSSL_SMALL_STACK) && !defined(WOLFSSL_SMALL_STACK_CACHE)
    data = (byte*)XMALLOC(DRBG_SHA512_SEED_LEN, drbg->heap,
        DYNAMIC_TYPE_TMP_BUFFER);
    digest = (byte*)XMALLOC(WC_SHA512_DIGEST_SIZE, drbg->heap,
        DYNAMIC_TYPE_DIGEST);
    if (data == NULL || digest == NULL) {
        XFREE(digest, drbg->heap, DYNAMIC_TYPE_DIGEST);
        XFREE(data, drbg->heap, DYNAMIC_TYPE_TMP_BUFFER);
        return DRBG_FAILURE;
    }
#endif

    /* Special case: outSz is 0 and out is NULL. Generate a block to save for
     * the continuous test. */
    if (outSz == 0) {
        outSz = 1;
    }

    len = (outSz / OUTPUT_BLOCK_LEN_SHA512)
        + ((outSz % OUTPUT_BLOCK_LEN_SHA512) ? 1 : 0);

    XMEMCPY(data, V, DRBG_SHA512_SEED_LEN);
    for (i = 0; i < len; i++) {
#ifndef WOLFSSL_SMALL_STACK_CACHE
    #if defined(WOLFSSL_ASYNC_CRYPT) || defined(WOLF_CRYPTO_CB)
        ret = wc_InitSha512_ex(sha, drbg->heap, drbg->devId);
    #else
        ret = wc_InitSha512(sha);
    #endif
        if (ret == 0)
#endif
            ret = wc_Sha512Update(sha, data, DRBG_SHA512_SEED_LEN);
        if (ret == 0)
            ret = wc_Sha512Final(sha, digest);
#ifndef WOLFSSL_SMALL_STACK_CACHE
        wc_Sha512Free(sha);
#endif

        if (ret == 0) {
            if (out != NULL && outSz != 0) {
                if (outSz >= OUTPUT_BLOCK_LEN_SHA512) {
                    XMEMCPY(out, digest, OUTPUT_BLOCK_LEN_SHA512);
                    outSz -= OUTPUT_BLOCK_LEN_SHA512;
                    out += OUTPUT_BLOCK_LEN_SHA512;
                    array_add_one(data, DRBG_SHA512_SEED_LEN);
                }
                else {
                    XMEMCPY(out, digest, outSz);
                    outSz = 0;
                }
            }
        }
        else {
            break;
        }
    }
    ForceZero(data, DRBG_SHA512_SEED_LEN);

#ifndef WOLFSSL_SMALL_STACK_CACHE
    WC_FREE_VAR_EX(digest, drbg->heap, DYNAMIC_TYPE_DIGEST);
    WC_FREE_VAR_EX(data, drbg->heap, DYNAMIC_TYPE_TMP_BUFFER);
#endif

    return (ret == 0) ? DRBG_SUCCESS : DRBG_FAILURE;
}

/* Returns: DRBG_SUCCESS, DRBG_NEED_RESEED, or DRBG_FAILURE */
static int Hash512_DRBG_Generate(DRBG_SHA512_internal* drbg, byte* out,
                                 word32 outSz,
                                 const byte* additional, word32 additionalSz)
{
    int ret;
#ifdef WOLFSSL_SMALL_STACK_CACHE
    wc_Sha512* sha = &drbg->sha512;
#else
    wc_Sha512 sha[1];
#endif
    byte type;
    word64 reseedCtr;

    if (drbg == NULL) {
        return DRBG_FAILURE;
    }

    if (drbg->reseedCtr >= WC_RESEED_INTERVAL) {
        return DRBG_NEED_RESEED;
    }
    else {
    #if defined(WOLFSSL_SMALL_STACK_CACHE)
        byte* digest = drbg->digest_scratch;
    #elif defined(WOLFSSL_SMALL_STACK)
        byte* digest = (byte*)XMALLOC(WC_SHA512_DIGEST_SIZE, drbg->heap,
            DYNAMIC_TYPE_DIGEST);
        if (digest == NULL)
            return DRBG_FAILURE;
    #else
        byte digest[WC_SHA512_DIGEST_SIZE];
    #endif

        type = drbgGenerateH;
        reseedCtr = drbg->reseedCtr;

        /* SP 800-90A Section 10.1.1.4 step 2:
         * If additional_input != Null, w = Hash(0x02 || V || additional_input),
         * V = (V + w) mod 2^seedlen */
        ret = DRBG_SUCCESS;
        if (additional != NULL && additionalSz > 0) {
            byte addType = drbgGenerateW; /* 0x02 */
#ifndef WOLFSSL_SMALL_STACK_CACHE
        #if defined(WOLFSSL_ASYNC_CRYPT) || defined(WOLF_CRYPTO_CB)
            ret = wc_InitSha512_ex(sha, drbg->heap, drbg->devId);
        #else
            ret = wc_InitSha512(sha);
        #endif
            if (ret == 0)
#endif
                ret = wc_Sha512Update(sha, &addType, sizeof(addType));
            if (ret == 0)
                ret = wc_Sha512Update(sha, drbg->V, sizeof(drbg->V));
            if (ret == 0)
                ret = wc_Sha512Update(sha, additional, additionalSz);
            if (ret == 0)
                ret = wc_Sha512Final(sha, digest);
#ifndef WOLFSSL_SMALL_STACK_CACHE
            wc_Sha512Free(sha);
#endif
            if (ret == 0)
                array_add(drbg->V, sizeof(drbg->V), digest,
                          WC_SHA512_DIGEST_SIZE);
        }

        if (ret == 0)
            ret = Hash512_gen(drbg, out, outSz, drbg->V);
        if (ret == DRBG_SUCCESS) {
#ifndef WOLFSSL_SMALL_STACK_CACHE
        #if defined(WOLFSSL_ASYNC_CRYPT) || defined(WOLF_CRYPTO_CB)
            ret = wc_InitSha512_ex(sha, drbg->heap, drbg->devId);
        #else
            ret = wc_InitSha512(sha);
        #endif
            if (ret == 0)
#endif
                ret = wc_Sha512Update(sha, &type, sizeof(type));
            if (ret == 0)
                ret = wc_Sha512Update(sha, drbg->V, sizeof(drbg->V));
            if (ret == 0)
                ret = wc_Sha512Final(sha, digest);

#ifndef WOLFSSL_SMALL_STACK_CACHE
            wc_Sha512Free(sha);
#endif

            if (ret == 0) {
                array_add(drbg->V, sizeof(drbg->V), digest,
                          WC_SHA512_DIGEST_SIZE);
                array_add(drbg->V, sizeof(drbg->V), drbg->C, sizeof(drbg->C));
            #ifdef LITTLE_ENDIAN_ORDER
                reseedCtr = ByteReverseWord64(reseedCtr);
            #endif
                array_add(drbg->V, sizeof(drbg->V),
                                          (byte*)&reseedCtr, sizeof(reseedCtr));
                ret = DRBG_SUCCESS;
            }
            drbg->reseedCtr++;
        }
        ForceZero(digest, WC_SHA512_DIGEST_SIZE);
    #if defined(WOLFSSL_SMALL_STACK) && !defined(WOLFSSL_SMALL_STACK_CACHE)
        XFREE(digest, drbg->heap, DYNAMIC_TYPE_DIGEST);
    #endif
    }

    return (ret == 0) ? DRBG_SUCCESS : DRBG_FAILURE;
}

/* Returns: DRBG_SUCCESS or DRBG_FAILURE */
static int Hash512_DRBG_Init(DRBG_SHA512_internal* drbg, const byte* seed,
                             word32 seedSz, const byte* nonce, word32 nonceSz,
                             const byte* perso, word32 persoSz)
{
    if (seed == NULL)
        return DRBG_FAILURE;

    if (Hash512_df(drbg, drbg->V, sizeof(drbg->V), drbgInitV, seed, seedSz,
                                              nonce, nonceSz,
                                              perso, persoSz) == DRBG_SUCCESS &&
        Hash512_df(drbg, drbg->C, sizeof(drbg->C), drbgInitC, drbg->V,
                                    sizeof(drbg->V), NULL, 0,
                                    NULL, 0) == DRBG_SUCCESS) {

        drbg->reseedCtr = 1;
        return DRBG_SUCCESS;
    }
    else {
        return DRBG_FAILURE;
    }
}

/* Returns: DRBG_SUCCESS or DRBG_FAILURE */
static int Hash512_DRBG_Instantiate(DRBG_SHA512_internal* drbg,
                                    const byte* seed, word32 seedSz,
                                    const byte* nonce, word32 nonceSz,
                                    const byte* perso, word32 persoSz,
                                    void* heap, int devId)
{
    int ret = DRBG_FAILURE;

    XMEMSET(drbg, 0, sizeof(DRBG_SHA512_internal));
    drbg->heap = heap;
#if defined(WOLFSSL_ASYNC_CRYPT) || defined(WOLF_CRYPTO_CB)
    drbg->devId = devId;
#else
    (void)devId;
#endif

#ifdef WOLFSSL_SMALL_STACK_CACHE
    #if defined(WOLFSSL_ASYNC_CRYPT) || defined(WOLF_CRYPTO_CB)
        ret = wc_InitSha512_ex(&drbg->sha512, drbg->heap, drbg->devId);
    #else
        ret = wc_InitSha512(&drbg->sha512);
    #endif
    if (ret != 0)
        return ret;
#endif

    if (seed != NULL)
        ret = Hash512_DRBG_Init(drbg, seed, seedSz, nonce, nonceSz,
                                perso, persoSz);
    return ret;
}

/* Returns: DRBG_SUCCESS or DRBG_FAILURE */
static int Hash512_DRBG_Uninstantiate(DRBG_SHA512_internal* drbg)
{
    word32 i;
    int    compareSum = 0;
    byte*  compareDrbg = (byte*)drbg;

#ifdef WOLFSSL_SMALL_STACK_CACHE
    wc_Sha512Free(&drbg->sha512);
#endif

    ForceZero(drbg, sizeof(DRBG_SHA512_internal));

    for (i = 0; i < sizeof(DRBG_SHA512_internal); i++) {
        compareSum |= compareDrbg[i] ^ 0;
    }

    return (compareSum == 0) ? DRBG_SUCCESS : DRBG_FAILURE;
}

#endif /* WOLFSSL_DRBG_SHA512 */


/* FIPS 140-3 IG 10.3.A / SP800-90B Health Tests for Seed Data
 *
 * These tests replace the older FIPS 140-2 Continuous Random Number Generator
 * Test (CRNGT) with more mathematically robust statistical tests per
 * ISO 19790 / SP800-90B requirements.
 *
 * When HAVE_ENTROPY_MEMUSE is defined, the wolfentropy.c jitter-based TRNG
 * performs another set of these health tests, but those are on the noise not
 * the conditioned output so we still need to retest here even in that case
 * to evaluate the conditioned output for the same behavior. These tests ensure
 * the seed data meets basic entropy requirements regardless of the source.
 */

/* SP800-90B 4.4.1 - Repetition Count Test
 * Detects if the noise source becomes "stuck" producing repeated output.
 *
 * C = 1 + ceil(-log2(alpha) / H)
 * For alpha = 2^-30 (false positive probability) and H = 1 (min entropy):
 * C = 1 + ceil(30 / 1) = 31
 */
#ifndef WC_RNG_SEED_RCT_CUTOFF
    #define WC_RNG_SEED_RCT_CUTOFF 31
#endif

/* SP800-90B 4.4.2 - Adaptive Proportion Test
 * Monitors if a particular sample value appears too frequently within a
 * window of samples, indicating loss of entropy.
 *
 * Window size W = 512 for non-binary alphabet (byte values 0-255)
 * C = 1 + CRITBINOM(W, 2^(-H), 1-alpha)
 * For alpha = 2^-30 and H = 1, W = 512:
 * C = 1 + CRITBINOM(512, 0.5, 1-2^-30) = 325
 */
#ifndef WC_RNG_SEED_APT_WINDOW
    #define WC_RNG_SEED_APT_WINDOW 512
#endif
#ifndef WC_RNG_SEED_APT_CUTOFF
    #define WC_RNG_SEED_APT_CUTOFF 325
#endif

int wc_RNG_TestSeed(const byte* seed, word32 seedSz)
{
    int ret = 0;

    word32 i;
    int rctFailed = 0;
    int aptFailed = 0;

    if (seed == NULL || seedSz < SEED_BLOCK_SZ) {
        return BAD_FUNC_ARG;
    }

    /* SP800-90B 4.4.1 - Repetition Count Test (RCT)
     * Check for consecutive identical bytes that would indicate a stuck
     * entropy source. Fail if we see WC_RNG_SEED_RCT_CUTOFF or more
     * consecutive identical values.
     *
     * Constant-time implementation: always process full seed, accumulate
     * failure status without early exit to prevent timing side-channels.
     */
    {
        int repCount = 1;
        byte prevByte = seed[0];

        for (i = 1; i < seedSz; i++) {
            /* Constant-time: always evaluate both branches effects */
            int match = (seed[i] == prevByte);
            /* If match, increment count, if not, reset to 1 */
            repCount = (match * (repCount + 1)) + (!match * 1);
            /* Update prevByte only when not matching (new value) */
            prevByte = (byte) ((match * prevByte) + (!match * seed[i]));
            /* Accumulate failure flag - once set, stays set */
            rctFailed |= (repCount >= WC_RNG_SEED_RCT_CUTOFF);
        }
    }

    /* SP800-90B 4.4.2 - Adaptive Proportion Test (APT)
     * Check that no single byte value appears too frequently within
     * a sliding window. This detects bias in the entropy source.
     *
     * For seeds smaller than the window size, we test the entire seed.
     * For larger seeds, we use a sliding window approach.
     *
     * Constant-time implementation: always process full seed and check
     * all counts to prevent timing side-channels.
     */
    {
    #if defined(WOLFSSL_SMALL_STACK) && !defined(WOLFSSL_SMALL_STACK_CACHE)
        word16* byteCounts = NULL;
    #else
        word16 byteCounts[MAX_ENTROPY_BITS];
    #endif
        word32 windowSize = min(seedSz, (word32)WC_RNG_SEED_APT_WINDOW);
        word32 windowStart = 0;
        word32 newIdx;

    #if defined(WOLFSSL_SMALL_STACK) && !defined(WOLFSSL_SMALL_STACK_CACHE)
        byteCounts = (word16*)XMALLOC(MAX_ENTROPY_BITS * sizeof(word16), NULL,
                                      DYNAMIC_TYPE_TMP_BUFFER);
        if (byteCounts == NULL)
            return MEMORY_E;
    #endif
        XMEMSET(byteCounts, 0, MAX_ENTROPY_BITS * sizeof(word16));

        /* Initialize counts for first window */
        for (i = 0; i < windowSize; i++) {
            byteCounts[seed[i]]++;
        }

        /* Check first window - scan all 256 counts */
        for (i = 0; i < MAX_ENTROPY_BITS; i++) {
            aptFailed |= (byteCounts[i] >= WC_RNG_SEED_APT_CUTOFF);
        }

        /* Slide window through remaining seed data */
        while ((windowStart + windowSize) < seedSz) {
            /* Remove byte leaving the window */
            byteCounts[seed[windowStart]]--;
            windowStart++;

            /* Add byte entering the window */
            newIdx = windowStart + windowSize - 1;
            byteCounts[seed[newIdx]]++;

            /* Accumulate failure flag for new byte's count */
            aptFailed |= (byteCounts[seed[newIdx]] >= WC_RNG_SEED_APT_CUTOFF);
        }

    #if defined(WOLFSSL_SMALL_STACK) && !defined(WOLFSSL_SMALL_STACK_CACHE)
        XFREE(byteCounts, NULL, DYNAMIC_TYPE_TMP_BUFFER);
    #endif
    }

    /* Set return code based on accumulated failure flags */
    if (rctFailed) {
        ret = ENTROPY_RT_E;
    }
    else if (aptFailed) {
        ret = ENTROPY_APT_E;
    }

    return ret;
}
/* Runtime DRBG disable/enable API -- only available in non-selftest and
 * FIPS v7+ builds (older FIPS/selftest random.c doesn't have these) */
#if !defined(HAVE_SELFTEST) && \
    (!defined(HAVE_FIPS) || FIPS_VERSION3_GE(7,0,0))
#ifndef NO_SHA256
int wc_Sha256Drbg_Disable(void)
{
    int ret;
#ifdef WOLFSSL_DRBG_SHA512
    ret = LockDrbgState();
    if (ret != 0)
        return ret;
    if (sha512DrbgDisabled) {
        UnlockDrbgState();
        return BAD_STATE_E;  /* can't disable both */
    }
    sha256DrbgDisabled = 1;
    UnlockDrbgState();
    return 0;
#else
    (void)ret;
    return NOT_COMPILED_IN;
#endif
}

int wc_Sha256Drbg_Enable(void)
{
    int ret = LockDrbgState();
    if (ret != 0)
        return ret;
    sha256DrbgDisabled = 0;
    UnlockDrbgState();
    return 0;
}

int wc_Sha256Drbg_IsDisabled(void)
{
    int val;
    if (LockDrbgState() != 0)
        return 1; /* fail-safe: report disabled on mutex error */
    val = sha256DrbgDisabled;
    UnlockDrbgState();
    return val;
}
#else
/* When SHA-256 is not compiled in, these are stubs */
int wc_Sha256Drbg_Disable(void) { return NOT_COMPILED_IN; }
int wc_Sha256Drbg_Enable(void) { return 0; }
int wc_Sha256Drbg_IsDisabled(void) { return 1; } /* always disabled */
#endif /* !NO_SHA256 */
#endif /* !HAVE_SELFTEST && (!HAVE_FIPS || FIPS v7+) */

#ifdef WOLFSSL_DRBG_SHA512
int wc_Sha512Drbg_Disable(void)
{
    int ret = LockDrbgState();
    if (ret != 0)
        return ret;
#ifndef NO_SHA256
    if (sha256DrbgDisabled) {
        UnlockDrbgState();
        return BAD_STATE_E;  /* can't disable both */
    }
#endif
    sha512DrbgDisabled = 1;
    UnlockDrbgState();
    return 0;
}

int wc_Sha512Drbg_Enable(void)
{
    int ret = LockDrbgState();
    if (ret != 0)
        return ret;
    sha512DrbgDisabled = 0;
    UnlockDrbgState();
    return 0;
}

int wc_Sha512Drbg_IsDisabled(void)
{
    int val;
    if (LockDrbgState() != 0)
        return 1; /* fail-safe: report disabled on mutex error */
    val = sha512DrbgDisabled;
    UnlockDrbgState();
    return val;
}
#endif /* WOLFSSL_DRBG_SHA512 */

#endif /* HAVE_HASHDRBG */
/* End NIST DRBG Code */


static int _InitRng(WC_RNG* rng, byte* nonce, word32 nonceSz,
                    void* heap, int devId)
{
    int ret = 0;
#if defined(HAVE_HASHDRBG) && !defined(CUSTOM_RAND_GENERATE_BLOCK)
#if !defined(HAVE_FIPS) && defined(WOLFSSL_RNG_USE_FULL_SEED)
    word32 seedSz = SEED_SZ;
#else
    word32 seedSz = SEED_SZ + SEED_BLOCK_SZ;
#endif
    WC_DECLARE_VAR(seed, byte, MAX_SEED_SZ, rng->heap);
#ifdef WOLFSSL_SMALL_STACK_CACHE
    int drbg_scratch_instantiated = 0;
#endif
#endif

    (void)nonce;
    (void)nonceSz;

    if (rng == NULL)
        return BAD_FUNC_ARG;
    if (nonce == NULL && nonceSz != 0)
        return BAD_FUNC_ARG;

    XMEMSET(rng, 0, sizeof(*rng));

#ifdef WOLFSSL_HEAP_TEST
    rng->heap = (void*)WOLFSSL_HEAP_TEST;
    (void)heap;
#else
    rng->heap = heap;
#endif
#if defined(HAVE_GETPID) && !defined(WOLFSSL_NO_GETPID)
    rng->pid = getpid();
#endif
#if defined(WOLFSSL_ASYNC_CRYPT) || defined(WOLF_CRYPTO_CB)
    rng->devId = devId;
    #if defined(WOLF_CRYPTO_CB)
        rng->seed.devId = devId;
    #endif
#else
    (void)devId;
#endif

#ifdef HAVE_HASHDRBG
    /* init the DBRG to known values */
#ifndef NO_SHA256
    rng->drbg = NULL;
    #ifdef WOLFSSL_SMALL_STACK_CACHE
    rng->drbg_scratch = NULL;
    #endif
#endif
#ifdef WOLFSSL_DRBG_SHA512
    rng->drbg512 = NULL;
    #ifdef WOLFSSL_SMALL_STACK_CACHE
    rng->drbg512_scratch = NULL;
    rng->health_check_scratch_512 = NULL;
    #endif
#endif
#ifdef WOLFSSL_SMALL_STACK_CACHE
    rng->newSeed_buf = NULL;
#ifndef NO_SHA256
    rng->health_check_scratch = NULL;
#endif
#endif
    rng->status = DRBG_NOT_INIT;

    /* Select DRBG type: prefer SHA-512 unless disabled or not compiled.
     * Hold the mutex for a consistent snapshot of both disable flags. */
#if !defined(HAVE_SELFTEST) && (!defined(HAVE_FIPS) || FIPS_VERSION3_GE(7,0,0))
    ret = LockDrbgState();
    if (ret != 0)
        return ret;
#ifdef WOLFSSL_DRBG_SHA512
    if (!sha512DrbgDisabled)
        rng->drbgType = WC_DRBG_SHA512;
    else
#endif
#ifndef NO_SHA256
    if (!sha256DrbgDisabled)
        rng->drbgType = WC_DRBG_SHA256;
    else
#endif
    {
        UnlockDrbgState();
        return BAD_STATE_E; /* no DRBG available */
    }
    UnlockDrbgState();
#else
    rng->drbgType = WC_DRBG_SHA256;
#endif
#endif

#if defined(HAVE_INTEL_RDSEED) || defined(HAVE_INTEL_RDRAND) || \
    defined(HAVE_AMD_RDSEED)
    /* init the intel RD seed and/or rand */
    wc_InitRng_IntelRD();
#endif

    /* configure async RNG source if available */
#ifdef WOLFSSL_ASYNC_CRYPT
    ret = wolfAsync_DevCtxInit(&rng->asyncDev, WOLFSSL_ASYNC_MARKER_RNG,
                                                        rng->heap, rng->devId);
    if (ret != 0) {
    #ifdef HAVE_HASHDRBG
        rng->status = DRBG_OK;
    #endif
        return ret;
    }
#endif

#ifdef HAVE_INTEL_RDRAND
    /* if CPU supports RDRAND, use it directly and by-pass DRBG init */
    if (IS_INTEL_RDRAND(intel_flags)) {
    #ifdef HAVE_HASHDRBG
        rng->status = DRBG_OK;
    #endif
        return 0;
    }
#endif

#ifdef WOLFSSL_XILINX_CRYPT_VERSAL
    ret = wc_VersalTrngInit(nonce, nonceSz);
    if (ret) {
    #ifdef HAVE_HASHDRBG
        rng->status = DRBG_OK;
    #endif
        return ret;
    }
#endif

#if defined(WOLFSSL_KEEP_RNG_SEED_FD_OPEN) && !defined(USE_WINDOWS_API)
    if (!rng->seed.seedFdOpen)
        rng->seed.fd = XBADFD;
#endif

#ifdef CUSTOM_RAND_GENERATE_BLOCK
    ret = 0; /* success */
#else

 /* not CUSTOM_RAND_GENERATE_BLOCK follows */
#ifdef HAVE_HASHDRBG
    if (nonceSz == 0) {
        seedSz = MAX_SEED_SZ;
    }

#ifndef NO_SHA256
    if (rng->drbgType == WC_DRBG_SHA256) {
    #if !defined(WOLFSSL_NO_MALLOC) || defined(WOLFSSL_STATIC_MEMORY)
        rng->drbg =
            (struct DRBG*)XMALLOC(sizeof(DRBG_internal), rng->heap,
                                  DYNAMIC_TYPE_RNG);
        if (rng->drbg == NULL) {
        #if defined(DEBUG_WOLFSSL)
            WOLFSSL_MSG_EX("_InitRng XMALLOC failed to allocate %d bytes",
                           sizeof(DRBG_internal));
        #endif
            ret = MEMORY_E;
            rng->status = DRBG_FAILED;
        }
    #else
        rng->drbg = (struct DRBG*)&rng->drbg_data;
    #endif /* WOLFSSL_NO_MALLOC or WOLFSSL_STATIC_MEMORY */

    #ifdef WOLFSSL_SMALL_STACK_CACHE
        if (ret == 0) {
            rng->drbg_scratch =
                (DRBG_internal *)XMALLOC(sizeof(DRBG_internal), rng->heap,
                                         DYNAMIC_TYPE_RNG);
            if (rng->drbg_scratch == NULL) {
    #if defined(DEBUG_WOLFSSL)
                WOLFSSL_MSG_EX("_InitRng XMALLOC failed to allocate %d bytes",
                               sizeof(DRBG_internal));
    #endif
                ret = MEMORY_E;
                rng->status = DRBG_FAILED;
            }
        }

        if (ret == 0) {
            ret = Hash_DRBG_Instantiate((DRBG_internal *)rng->drbg_scratch,
                        NULL, 0, NULL, 0, NULL, 0, rng->heap, devId);
            if (ret == 0)
                drbg_scratch_instantiated = 1;
        }

        if (ret == 0) {
            rng->health_check_scratch =
                (byte *)XMALLOC(RNG_HEALTH_TEST_CHECK_SIZE, rng->heap,
                                DYNAMIC_TYPE_TMP_BUFFER);
            if (rng->health_check_scratch == NULL) {
                ret = MEMORY_E;
                rng->status = DRBG_FAILED;
            }
        }
    #endif /* WOLFSSL_SMALL_STACK_CACHE */
    } /* WC_DRBG_SHA256 */
#endif /* !NO_SHA256 */

#ifdef WOLFSSL_DRBG_SHA512
    if (rng->drbgType == WC_DRBG_SHA512) {
    #if !defined(WOLFSSL_NO_MALLOC) || defined(WOLFSSL_STATIC_MEMORY)
        rng->drbg512 =
            (struct DRBG_SHA512*)XMALLOC(sizeof(DRBG_SHA512_internal),
                                         rng->heap, DYNAMIC_TYPE_RNG);
        if (rng->drbg512 == NULL) {
        #if defined(DEBUG_WOLFSSL)
            WOLFSSL_MSG_EX("_InitRng XMALLOC failed to allocate %d bytes",
                           sizeof(DRBG_SHA512_internal));
        #endif
            ret = MEMORY_E;
            rng->status = DRBG_FAILED;
        }
    #else
        rng->drbg512 = (struct DRBG_SHA512*)&rng->drbg512_data;
    #endif

    #ifdef WOLFSSL_SMALL_STACK_CACHE
        if (ret == 0) {
            rng->drbg512_scratch =
                (DRBG_SHA512_internal *)XMALLOC(sizeof(DRBG_SHA512_internal),
                    rng->heap, DYNAMIC_TYPE_RNG);
            if (rng->drbg512_scratch == NULL) {
                ret = MEMORY_E;
                rng->status = DRBG_FAILED;
            }
        }

        if (ret == 0) {
            ret = Hash512_DRBG_Instantiate(rng->drbg512_scratch,
                        NULL, 0, NULL, 0, NULL, 0, rng->heap, devId);
            if (ret == 0)
                drbg_scratch_instantiated = 1;
        }

        if (ret == 0) {
            rng->health_check_scratch_512 =
                (byte *)XMALLOC(RNG_HEALTH_TEST_CHECK_SIZE_SHA512, rng->heap,
                                DYNAMIC_TYPE_TMP_BUFFER);
            if (rng->health_check_scratch_512 == NULL) {
                ret = MEMORY_E;
                rng->status = DRBG_FAILED;
            }
        }
    #endif /* WOLFSSL_SMALL_STACK_CACHE */
    } /* WC_DRBG_SHA512 */
#endif /* WOLFSSL_DRBG_SHA512 */

    /* newSeed_buf shared by both DRBG types for PollAndReSeed */
#ifdef WOLFSSL_SMALL_STACK_CACHE
    if (ret == 0) {
        rng->newSeed_buf = (byte*)XMALLOC(SEED_SZ + SEED_BLOCK_SZ, rng->heap,
                           DYNAMIC_TYPE_SEED);
        if (rng->newSeed_buf == NULL) {
            ret = MEMORY_E;
            rng->status = DRBG_FAILED;
        }
    }
#endif /* WOLFSSL_SMALL_STACK_CACHE */

    if (ret == 0) {
        ret = wc_RNG_HealthTestLocal(rng, 0, rng->heap, devId);
        if (ret != 0) {
        #if defined(DEBUG_WOLFSSL)
            WOLFSSL_MSG_EX("wc_RNG_HealthTestLocal failed err = %d", ret);
        #endif
            ret = DRBG_CONT_FAILURE;
        }
    }

    #ifdef WOLFSSL_SMALL_STACK
    if (ret == 0) {
        WC_ALLOC_VAR_EX(seed, byte, MAX_SEED_SZ, rng->heap, DYNAMIC_TYPE_SEED, WC_DO_NOTHING);
        if (seed == NULL) {
            ret = MEMORY_E;
            rng->status = DRBG_FAILED;
        }
    }
    #endif

    if (ret != 0) {
#if defined(DEBUG_WOLFSSL)
        WOLFSSL_MSG_EX("_InitRng failed. err = %d", ret);
#endif
    }
    else {
#ifdef WC_RNG_SEED_CB
            if (seedCb == NULL) {
                ret = DRBG_NO_SEED_CB;
            }
            else {
                ret = seedCb(&rng->seed, seed, seedSz);
                if (ret != 0) {
#ifdef WC_VERBOSE_RNG
                    WOLFSSL_DEBUG_PRINTF(
                        "ERROR: seedCb in _InitRng() failed with err = %d",
                        ret);
#endif
                    ret = DRBG_FAILURE;
                }
            }
#else
            ret = wc_GenerateSeed(&rng->seed, seed, seedSz);
#endif /* WC_RNG_SEED_CB */
            if (ret != 0) {
    #if defined(DEBUG_WOLFSSL)
                WOLFSSL_MSG_EX("Seed generation failed... %d", ret);
    #elif defined(WC_VERBOSE_RNG)
                WOLFSSL_DEBUG_PRINTF(
                    "ERROR: wc_GenerateSeed() in _InitRng() failed with err %d",
                    ret);
    #endif
                ret = DRBG_FAILURE;
                rng->status = DRBG_FAILED;
            }

            if (ret == 0)
                ret = wc_RNG_TestSeed(seed, seedSz);
    #if defined(DEBUG_WOLFSSL)
            if (ret != 0) {
                WOLFSSL_MSG_EX("wc_RNG_TestSeed failed... %d", ret);
            }
    #elif defined(WC_VERBOSE_RNG)
            if (ret != DRBG_SUCCESS) {
                WOLFSSL_DEBUG_PRINTF(
                    "ERROR: wc_RNG_TestSeed() in _InitRng() returned err %d.",
                    ret);
            }
    #endif

            if (ret == DRBG_SUCCESS) {
#ifndef NO_SHA256
                if (rng->drbgType == WC_DRBG_SHA256)
                    ret = Hash_DRBG_Instantiate((DRBG_internal *)rng->drbg,
                #if defined(HAVE_FIPS) || !defined(WOLFSSL_RNG_USE_FULL_SEED)
                                seed + SEED_BLOCK_SZ, seedSz - SEED_BLOCK_SZ,
                #else
                                seed, seedSz,
                #endif
                                nonce, nonceSz, NULL, 0, rng->heap, devId);
#endif
#ifdef WOLFSSL_DRBG_SHA512
                if (rng->drbgType == WC_DRBG_SHA512)
                    ret = Hash512_DRBG_Instantiate(
                                (DRBG_SHA512_internal *)rng->drbg512,
                #if defined(HAVE_FIPS) || !defined(WOLFSSL_RNG_USE_FULL_SEED)
                                seed + SEED_BLOCK_SZ, seedSz - SEED_BLOCK_SZ,
                #else
                                seed, seedSz,
                #endif
                                nonce, nonceSz, NULL, 0, rng->heap, devId);
#endif
            }
    } /* ret == 0 */

    #ifdef WOLFSSL_SMALL_STACK
    if (seed)
    #endif
    {
        ForceZero(seed, seedSz);
    }
    WC_FREE_VAR_EX(seed, rng->heap, DYNAMIC_TYPE_SEED);

    if (ret != DRBG_SUCCESS) {
    #ifndef NO_SHA256
        if (rng->drbgType == WC_DRBG_SHA256) {
        #if !defined(WOLFSSL_NO_MALLOC) || defined(WOLFSSL_STATIC_MEMORY)
            XFREE(rng->drbg, rng->heap, DYNAMIC_TYPE_RNG);
        #endif
            rng->drbg = NULL;
        #ifdef WOLFSSL_SMALL_STACK_CACHE
            XFREE(rng->health_check_scratch, rng->heap,
                   DYNAMIC_TYPE_TMP_BUFFER);
            rng->health_check_scratch = NULL;
            if (drbg_scratch_instantiated)
                (void)Hash_DRBG_Uninstantiate(
                    (DRBG_internal *)rng->drbg_scratch);
            XFREE(rng->drbg_scratch, rng->heap, DYNAMIC_TYPE_RNG);
            rng->drbg_scratch = NULL;
        #endif
        }
    #endif /* !NO_SHA256 */
    #ifdef WOLFSSL_DRBG_SHA512
        if (rng->drbgType == WC_DRBG_SHA512) {
        #if !defined(WOLFSSL_NO_MALLOC) || defined(WOLFSSL_STATIC_MEMORY)
            XFREE(rng->drbg512, rng->heap, DYNAMIC_TYPE_RNG);
        #endif
            rng->drbg512 = NULL;
        #ifdef WOLFSSL_SMALL_STACK_CACHE
            XFREE(rng->health_check_scratch_512, rng->heap,
                   DYNAMIC_TYPE_TMP_BUFFER);
            rng->health_check_scratch_512 = NULL;
            if (drbg_scratch_instantiated)
                (void)Hash512_DRBG_Uninstantiate(rng->drbg512_scratch);
            XFREE(rng->drbg512_scratch, rng->heap, DYNAMIC_TYPE_RNG);
            rng->drbg512_scratch = NULL;
        #endif
        }
    #endif
    #ifdef WOLFSSL_SMALL_STACK_CACHE
        XFREE(rng->newSeed_buf, rng->heap, DYNAMIC_TYPE_SEED);
        rng->newSeed_buf = NULL;
    #endif
    }
    /* else wc_RNG_HealthTestLocal was successful */

    if (ret == DRBG_SUCCESS) {
#ifdef WOLFSSL_CHECK_MEM_ZERO
    #ifndef NO_SHA256
        if (rng->drbgType == WC_DRBG_SHA256) {
            struct DRBG_internal* drbg = (struct DRBG_internal*)rng->drbg;
            wc_MemZero_Add("DRBG V", &drbg->V, sizeof(drbg->V));
            wc_MemZero_Add("DRBG C", &drbg->C, sizeof(drbg->C));
        }
    #endif
#endif

        rng->status = DRBG_OK;
        ret = 0;
    }
    else if (ret == DRBG_CONT_FAILURE) {
        rng->status = DRBG_CONT_FAILED;
        ret = DRBG_CONT_FIPS_E;
    }
    else if (ret == DRBG_FAILURE) {
        rng->status = DRBG_FAILED;
        ret = RNG_FAILURE_E;
    }
    else {
        rng->status = DRBG_FAILED;
    }
#endif /* HAVE_HASHDRBG */
#endif /* CUSTOM_RAND_GENERATE_BLOCK */

    return ret;
}


WOLFSSL_ABI
WC_RNG* wc_rng_new(byte* nonce, word32 nonceSz, void* heap)
{
    int ret = 0;
    WC_RNG* rng = NULL;

    /* Assume if WC_USE_DEVID it is intended for default usage */
#ifdef WC_USE_DEVID
    ret = wc_rng_new_ex(&rng, nonce, nonceSz, heap, WC_USE_DEVID);
#else
    ret = wc_rng_new_ex(&rng, nonce, nonceSz, heap, INVALID_DEVID);
#endif

    if (ret != 0) {
        return NULL;
    }

    return rng;
}


int wc_rng_new_ex(WC_RNG **rng, byte* nonce, word32 nonceSz,
                  void* heap, int devId)
{
    int ret;

    if (rng == NULL) {
        return BAD_FUNC_ARG;
    }

    *rng = (WC_RNG*)XMALLOC(sizeof(WC_RNG), heap, DYNAMIC_TYPE_RNG);
    if (*rng == NULL) {
        return MEMORY_E;
    }

    ret = _InitRng(*rng, nonce, nonceSz, heap, devId);
    if (ret != 0) {
        XFREE(*rng, heap, DYNAMIC_TYPE_RNG);
        *rng = NULL;
    }

    return ret;
}


WOLFSSL_ABI
void wc_rng_free(WC_RNG* rng)
{
    if (rng) {
        void* heap = rng->heap;

        wc_FreeRng(rng);
        ForceZero(rng, sizeof(WC_RNG));
        XFREE(rng, heap, DYNAMIC_TYPE_RNG);
        (void)heap;
    }
}

WOLFSSL_ABI
int wc_InitRng(WC_RNG* rng)
{
    return _InitRng(rng, NULL, 0, NULL, INVALID_DEVID);
}


int wc_InitRng_ex(WC_RNG* rng, void* heap, int devId)
{
    return _InitRng(rng, NULL, 0, heap, devId);
}


int wc_InitRngNonce(WC_RNG* rng, byte* nonce, word32 nonceSz)
{
    return _InitRng(rng, nonce, nonceSz, NULL, INVALID_DEVID);
}


int wc_InitRngNonce_ex(WC_RNG* rng, byte* nonce, word32 nonceSz,
                       void* heap, int devId)
{
    return _InitRng(rng, nonce, nonceSz, heap, devId);
}

#ifdef HAVE_HASHDRBG
static int PollAndReSeed(WC_RNG* rng)
{
    int ret   = DRBG_NEED_RESEED;
    int devId = INVALID_DEVID;
#if defined(WOLFSSL_ASYNC_CRYPT) || defined(WOLF_CRYPTO_CB)
    devId = rng->devId;
#endif
    if (wc_RNG_HealthTestLocal(rng, 1, rng->heap, devId) == 0) {
    #if defined(WOLFSSL_SMALL_STACK_CACHE)
        byte* newSeed = rng->newSeed_buf;
        ret = DRBG_SUCCESS;
    #elif defined(WOLFSSL_SMALL_STACK)
        byte* newSeed = (byte*)XMALLOC(SEED_SZ + SEED_BLOCK_SZ, rng->heap,
            DYNAMIC_TYPE_SEED);
        ret = (newSeed == NULL) ? MEMORY_E : DRBG_SUCCESS;
    #else
        byte newSeed[SEED_SZ + SEED_BLOCK_SZ];
        ret = DRBG_SUCCESS;
    #endif
        if (ret == DRBG_SUCCESS) {
        #ifdef WC_RNG_SEED_CB
            if (seedCb == NULL) {
                ret = DRBG_NO_SEED_CB;
            }
            else {
                ret = seedCb(&rng->seed, newSeed, SEED_SZ + SEED_BLOCK_SZ);
                if (ret != 0) {
    #ifdef WC_VERBOSE_RNG
                    WOLFSSL_DEBUG_PRINTF("ERROR: seedCb() in PollAndReSeed() "
                                         "failed with err %d", ret);
    #endif
                    ret = DRBG_FAILURE;
                }
            }
        #else
            ret = wc_GenerateSeed(&rng->seed, newSeed,
                              SEED_SZ + SEED_BLOCK_SZ);
            if (ret != 0) {
    #ifdef WC_VERBOSE_RNG
                WOLFSSL_DEBUG_PRINTF(
                    "ERROR: wc_GenerateSeed() in PollAndReSeed() failed with "
                    "err %d", ret);
    #endif
                ret = DRBG_FAILURE;
            }
        #endif
        }
        if (ret == DRBG_SUCCESS) {
            ret = wc_RNG_TestSeed(newSeed, SEED_SZ + SEED_BLOCK_SZ);
    #ifdef WC_VERBOSE_RNG
            if (ret != DRBG_SUCCESS)
                WOLFSSL_DEBUG_PRINTF(
                    "ERROR: wc_RNG_TestSeed() in PollAndReSeed() returned "
                    "err %d.", ret);
    #endif
        }
        if (ret == DRBG_SUCCESS) {
#ifndef NO_SHA256
            if (rng->drbgType == WC_DRBG_SHA256)
                ret = Hash_DRBG_Reseed((DRBG_internal *)rng->drbg,
                                       newSeed + SEED_BLOCK_SZ, SEED_SZ,
                                       NULL, 0);
#endif
#ifdef WOLFSSL_DRBG_SHA512
            if (rng->drbgType == WC_DRBG_SHA512)
                ret = Hash512_DRBG_Reseed(
                    (DRBG_SHA512_internal *)rng->drbg512,
                    newSeed + SEED_BLOCK_SZ, SEED_SZ, NULL, 0);
#endif
        }
    #if defined(WOLFSSL_SMALL_STACK) && !defined(WOLFSSL_SMALL_STACK_CACHE)
        if (newSeed != NULL) {
            ForceZero(newSeed, SEED_SZ + SEED_BLOCK_SZ);
        }
        XFREE(newSeed, rng->heap, DYNAMIC_TYPE_SEED);
    #else
        ForceZero(newSeed, sizeof(newSeed));
    #endif
    }
    else {
        ret = DRBG_CONT_FAILURE;
    }

    return ret;
}
#endif

/* place a generated block in output */
#ifdef WC_RNG_BANK_SUPPORT
static int wc_local_RNG_GenerateBlock(WC_RNG* rng, byte* output, word32 sz)
#else
WOLFSSL_ABI
int wc_RNG_GenerateBlock(WC_RNG* rng, byte* output, word32 sz)
#endif
{
    int ret;

    if (rng == NULL || output == NULL)
        return BAD_FUNC_ARG;

    if (sz == 0)
        return 0;

#ifdef WOLF_CRYPTO_CB
    #ifndef WOLF_CRYPTO_CB_FIND
    if (rng->devId != INVALID_DEVID)
    #endif
    {
        ret = wc_CryptoCb_RandomBlock(rng, output, sz);
        if (ret != WC_NO_ERR_TRACE(CRYPTOCB_UNAVAILABLE))
            return ret;
        /* fall-through when unavailable */
    }
#endif

#ifdef HAVE_INTEL_RDRAND
    if (IS_INTEL_RDRAND(intel_flags))
        return wc_GenerateRand_IntelRD(NULL, output, sz);
#endif

#if defined(WOLFSSL_SILABS_SE_ACCEL) && defined(WOLFSSL_SILABS_TRNG)
    return silabs_GenerateRand(output, sz);
#endif

#if defined(WOLFSSL_ASYNC_CRYPT)
    if (rng->asyncDev.marker == WOLFSSL_ASYNC_MARKER_RNG) {
        /* these are blocking */
    #ifdef HAVE_CAVIUM
        return NitroxRngGenerateBlock(rng, output, sz);
    #elif defined(HAVE_INTEL_QA) && defined(QAT_ENABLE_RNG)
        return IntelQaDrbg(&rng->asyncDev, output, sz);
    #else
        /* simulator not supported */
    #endif
    }
#endif

#ifdef CUSTOM_RAND_GENERATE_BLOCK
    XMEMSET(output, 0, sz);
    ret = (int)CUSTOM_RAND_GENERATE_BLOCK(output, sz);
    #ifdef WC_VERBOSE_RNG
    if (ret != 0)
        WOLFSSL_DEBUG_PRINTF(
            "ERROR: CUSTOM_RAND_GENERATE_BLOCK failed with err %d.", ret);
    #endif
#else

#ifdef HAVE_HASHDRBG
    if (sz > RNG_MAX_BLOCK_LEN)
        return BAD_FUNC_ARG;

    if (rng->status != DRBG_OK)
        return RNG_FAILURE_E;

#if defined(HAVE_GETPID) && !defined(WOLFSSL_NO_GETPID)
    if (rng->pid != getpid()) {
        rng->pid = getpid();
        ret = PollAndReSeed(rng);
        if (ret != DRBG_SUCCESS) {
            rng->status = DRBG_FAILED;
            return RNG_FAILURE_E;
        }
    }
#endif

#ifndef NO_SHA256
    if (rng->drbgType == WC_DRBG_SHA256) {
        ret = Hash_DRBG_Generate((DRBG_internal *)rng->drbg, output, sz,
                                 NULL, 0);
        if (ret == DRBG_NEED_RESEED) {
            ret = PollAndReSeed(rng);
            if (ret == DRBG_SUCCESS)
                ret = Hash_DRBG_Generate((DRBG_internal *)rng->drbg, output,
                                         sz, NULL, 0);
        }
    }
    else
#endif
#ifdef WOLFSSL_DRBG_SHA512
    if (rng->drbgType == WC_DRBG_SHA512) {
        ret = Hash512_DRBG_Generate((DRBG_SHA512_internal *)rng->drbg512,
                                    output, sz, NULL, 0);
        if (ret == DRBG_NEED_RESEED) {
            ret = PollAndReSeed(rng);
            if (ret == DRBG_SUCCESS)
                ret = Hash512_DRBG_Generate(
                    (DRBG_SHA512_internal *)rng->drbg512, output, sz,
                    NULL, 0);
        }
    }
    else
#endif
    {
        ret = DRBG_FAILURE;
    }

    if (ret == DRBG_SUCCESS) {
        ret = 0;
    }
    else if (ret == DRBG_CONT_FAILURE) {
        ret = DRBG_CONT_FIPS_E;
        rng->status = DRBG_CONT_FAILED;
    }
    else {
        ret = RNG_FAILURE_E;
        rng->status = DRBG_FAILED;
    }
#else

    /* if we get here then there is an RNG configuration error */
    ret = RNG_FAILURE_E;

#endif /* HAVE_HASHDRBG */
#endif /* CUSTOM_RAND_GENERATE_BLOCK */

    return ret;
}

#ifdef WC_RNG_BANK_SUPPORT
WOLFSSL_ABI
int wc_RNG_GenerateBlock(WC_RNG* rng, byte* output, word32 sz)
{
    if (rng == NULL)
        return BAD_FUNC_ARG;

    if (rng->status == WC_DRBG_BANKREF) {
        int ret;
        struct wc_rng_bank_inst *bank_inst = NULL;

        ret = wc_local_rng_bank_checkout_for_bankref(rng->bankref, &bank_inst);
        if (ret != 0)
            return ret;
        if (bank_inst == NULL)
            return BAD_STATE_E;
        ret = wc_local_RNG_GenerateBlock(WC_RNG_BANK_INST_TO_RNG(bank_inst),
                                         output, sz);
        {
            int checkin_ret = wc_rng_bank_checkin(rng->bankref, &bank_inst);
            if (checkin_ret != 0) {
#ifdef WC_VERBOSE_RNG
                WOLFSSL_DEBUG_PRINTF(
                    "ERROR: wc_RNG_GenerateBlock() wc_rng_bank_checkin() "
                    "failed with err %d.", checkin_ret);
#endif
                if (ret == 0)
                    ret = checkin_ret;
            }
        }
        return ret;
    }
    else
        return wc_local_RNG_GenerateBlock(rng, output, sz);
}
#endif

int wc_RNG_GenerateByte(WC_RNG* rng, byte* b)
{
    return wc_RNG_GenerateBlock(rng, b, 1);
}


int wc_FreeRng(WC_RNG* rng)
{
    int ret = 0;

    if (rng == NULL)
        return BAD_FUNC_ARG;

#ifdef WC_RNG_BANK_SUPPORT
    if (rng->status == WC_DRBG_BANKREF)
        return wc_BankRef_Release(rng);
#endif /* WC_RNG_BANK_SUPPORT */

#if defined(WOLFSSL_ASYNC_CRYPT)
    wolfAsync_DevCtxFree(&rng->asyncDev, WOLFSSL_ASYNC_MARKER_RNG);
#endif

#ifdef HAVE_HASHDRBG
#ifndef NO_SHA256
    if (rng->drbg != NULL) {
      if (Hash_DRBG_Uninstantiate((DRBG_internal *)rng->drbg) != DRBG_SUCCESS)
            ret = RNG_FAILURE_E;

    #if !defined(WOLFSSL_NO_MALLOC) || defined(WOLFSSL_STATIC_MEMORY)
        XFREE(rng->drbg, rng->heap, DYNAMIC_TYPE_RNG);
    #elif defined(WOLFSSL_CHECK_MEM_ZERO)
        wc_MemZero_Check(rng->drbg, sizeof(DRBG_internal));
    #endif
        rng->drbg = NULL;
    }

    #ifdef WOLFSSL_SMALL_STACK_CACHE
    /* Scratch buffers are tracked independently of rng->drbg so that a
     * partial-construction failure path that nulled rng->drbg early
     * (or any future restructure that does the same) cannot leak them.
     * Free on their own NULL check rather than nesting under drbg. */
    if (rng->drbg_scratch != NULL) {
        if (Hash_DRBG_Uninstantiate((DRBG_internal *)rng->drbg_scratch)
                            != DRBG_SUCCESS)
            ret = RNG_FAILURE_E;
        XFREE(rng->drbg_scratch, rng->heap, DYNAMIC_TYPE_RNG);
        rng->drbg_scratch = NULL;
    }
    if (rng->health_check_scratch != NULL) {
        XFREE(rng->health_check_scratch, rng->heap, DYNAMIC_TYPE_TMP_BUFFER);
        rng->health_check_scratch = NULL;
    }
    #endif
#endif /* !NO_SHA256 */

#ifdef WOLFSSL_DRBG_SHA512
    if (rng->drbg512 != NULL) {
        if (Hash512_DRBG_Uninstantiate(
                (DRBG_SHA512_internal *)rng->drbg512) != DRBG_SUCCESS)
            ret = RNG_FAILURE_E;

    #if !defined(WOLFSSL_NO_MALLOC) || defined(WOLFSSL_STATIC_MEMORY)
        XFREE(rng->drbg512, rng->heap, DYNAMIC_TYPE_RNG);
    #endif
        rng->drbg512 = NULL;
    }

    #ifdef WOLFSSL_SMALL_STACK_CACHE
    /* Same independence rationale as the SHA-256 scratch above. */
    if (rng->drbg512_scratch != NULL) {
        if (Hash512_DRBG_Uninstantiate(rng->drbg512_scratch)
                                != DRBG_SUCCESS)
            ret = RNG_FAILURE_E;
        XFREE(rng->drbg512_scratch, rng->heap, DYNAMIC_TYPE_RNG);
        rng->drbg512_scratch = NULL;
    }
    if (rng->health_check_scratch_512 != NULL) {
        XFREE(rng->health_check_scratch_512, rng->heap,
               DYNAMIC_TYPE_TMP_BUFFER);
        rng->health_check_scratch_512 = NULL;
    }
    #endif
#endif /* WOLFSSL_DRBG_SHA512 */

#ifdef WOLFSSL_SMALL_STACK_CACHE
    XFREE(rng->newSeed_buf, rng->heap, DYNAMIC_TYPE_SEED);
    rng->newSeed_buf = NULL;
#endif

    rng->status = DRBG_NOT_INIT;
#endif /* HAVE_HASHDRBG */

#ifdef WOLFSSL_XILINX_CRYPT_VERSAL
    /* don't overwrite previously set error */
    if (wc_VersalTrngReset() && !ret)
        ret = WC_HW_E;
#endif

#if defined(WOLFSSL_KEEP_RNG_SEED_FD_OPEN) && defined(XCLOSE) && \
    !defined(USE_WINDOWS_API)
    if(rng->seed.seedFdOpen && rng->seed.fd != XBADFD) {
        XCLOSE(rng->seed.fd);
        rng->seed.fd = XBADFD;
        rng->seed.seedFdOpen = 0;
    }
#endif

    return ret;
}

#ifdef HAVE_HASHDRBG
/* The original wc_RNG_HealthTest{,_ex} entry points operate on the SHA-256
 * Hash_DRBG (DRBG_internal). Gate them out under NO_SHA256; SHA-512-only
 * builds use wc_RNG_HealthTest_SHA512_ex declared further down. */
#ifndef NO_SHA256
int wc_RNG_HealthTest(int reseed, const byte* seedA, word32 seedASz,
                                  const byte* seedB, word32 seedBSz,
                                  byte* output, word32 outputSz)
{
    return wc_RNG_HealthTest_ex(reseed, NULL, 0,
                                seedA, seedASz, seedB, seedBSz,
                                output, outputSz,
                                NULL, INVALID_DEVID);
}


static int wc_RNG_HealthTest_ex_internal(DRBG_internal* drbg,
                                  int reseed, const byte* nonce, word32 nonceSz,
                                  const byte* seedA, word32 seedASz,
                                  const byte* seedB, word32 seedBSz,
                                  byte* output, word32 outputSz,
                                  void* heap, int devId)
{
    int ret = -1;

    if (seedA == NULL || output == NULL) {
        return BAD_FUNC_ARG;
    }

    if (reseed != 0 && seedB == NULL) {
        return BAD_FUNC_ARG;
    }

    if (outputSz != RNG_HEALTH_TEST_CHECK_SIZE) {
        return ret;
    }

#ifdef WOLFSSL_SMALL_STACK_CACHE
    (void)heap;
    (void)devId;

    if (Hash_DRBG_Init(drbg, seedA, seedASz, nonce, nonceSz,
                        NULL, 0) != 0) {
        goto exit_rng_ht;
    }
#else
    if (Hash_DRBG_Instantiate(drbg, seedA, seedASz, nonce, nonceSz,
                              NULL, 0, heap, devId) != 0) {
        goto exit_rng_ht;
    }
#endif

    if (reseed) {
        if (Hash_DRBG_Reseed(drbg, seedB, seedBSz, NULL, 0) != 0) {
            goto exit_rng_ht;
        }
    }

    /* This call to generate is prescribed by the NIST DRBGVS
     * procedure. The results are thrown away. The known
     * answer test checks the second block of DRBG out of
     * the generator to ensure the internal state is updated
     * as expected. */
    if (Hash_DRBG_Generate(drbg, output, outputSz, NULL, 0) != 0) {
        goto exit_rng_ht;
    }

    if (Hash_DRBG_Generate(drbg, output, outputSz, NULL, 0) != 0) {
        goto exit_rng_ht;
    }

    /* Mark success */
    ret = 0;

exit_rng_ht:

#ifndef WOLFSSL_SMALL_STACK_CACHE
    /* This is safe to call even if Hash_DRBG_Instantiate fails */
    if (Hash_DRBG_Uninstantiate(drbg) != 0) {
        ret = -1;
    }
#endif

    return ret;
}

int wc_RNG_HealthTest_ex(int reseed, const byte* nonce, word32 nonceSz,
                                  const byte* seedA, word32 seedASz,
                                  const byte* seedB, word32 seedBSz,
                                  byte* output, word32 outputSz,
                                  void* heap, int devId)
{
    int ret = -1;
    DRBG_internal* drbg;
#ifndef WOLFSSL_SMALL_STACK
    DRBG_internal  drbg_var;
#endif

#ifdef WOLFSSL_SMALL_STACK
    drbg = (DRBG_internal*)XMALLOC(sizeof(DRBG_internal), heap,
        DYNAMIC_TYPE_RNG);
    if (drbg == NULL) {
        return MEMORY_E;
    }
#else
    drbg = &drbg_var;
#endif

#ifdef WOLFSSL_SMALL_STACK_CACHE
    ret = Hash_DRBG_Instantiate(drbg,
                    NULL /* seed */, 0, NULL /* nonce */, 0,
                    NULL /* perso */, 0, heap, devId);
    if (ret == 0)
#endif
    {
        ret = wc_RNG_HealthTest_ex_internal(
                drbg, reseed, nonce, nonceSz, seedA, seedASz,
                seedB, seedBSz, output, outputSz, heap, devId);
#ifdef WOLFSSL_SMALL_STACK_CACHE
        Hash_DRBG_Uninstantiate(drbg);
#endif
    }
    WC_FREE_VAR_EX(drbg, heap, DYNAMIC_TYPE_RNG);

    return ret;
}
#endif /* !NO_SHA256 - wc_RNG_HealthTest{,_ex,_ex_internal} */


const FLASH_QUALIFIER byte seedA_data[] = {
    0x63, 0x36, 0x33, 0x77, 0xe4, 0x1e, 0x86, 0x46, 0x8d, 0xeb, 0x0a, 0xb4,
    0xa8, 0xed, 0x68, 0x3f, 0x6a, 0x13, 0x4e, 0x47, 0xe0, 0x14, 0xc7, 0x00,
    0x45, 0x4e, 0x81, 0xe9, 0x53, 0x58, 0xa5, 0x69, 0x80, 0x8a, 0xa3, 0x8f,
    0x2a, 0x72, 0xa6, 0x23, 0x59, 0x91, 0x5a, 0x9f, 0x8a, 0x04, 0xca, 0x68
};

const FLASH_QUALIFIER byte reseedSeedA_data[] = {
    0xe6, 0x2b, 0x8a, 0x8e, 0xe8, 0xf1, 0x41, 0xb6, 0x98, 0x05, 0x66, 0xe3,
    0xbf, 0xe3, 0xc0, 0x49, 0x03, 0xda, 0xd4, 0xac, 0x2c, 0xdf, 0x9f, 0x22,
    0x80, 0x01, 0x0a, 0x67, 0x39, 0xbc, 0x83, 0xd3
};

const FLASH_QUALIFIER byte outputA_data[] = {
    0x04, 0xee, 0xc6, 0x3b, 0xb2, 0x31, 0xdf, 0x2c, 0x63, 0x0a, 0x1a, 0xfb,
    0xe7, 0x24, 0x94, 0x9d, 0x00, 0x5a, 0x58, 0x78, 0x51, 0xe1, 0xaa, 0x79,
    0x5e, 0x47, 0x73, 0x47, 0xc8, 0xb0, 0x56, 0x62, 0x1c, 0x18, 0xbd, 0xdc,
    0xdd, 0x8d, 0x99, 0xfc, 0x5f, 0xc2, 0xb9, 0x20, 0x53, 0xd8, 0xcf, 0xac,
    0xfb, 0x0b, 0xb8, 0x83, 0x12, 0x05, 0xfa, 0xd1, 0xdd, 0xd6, 0xc0, 0x71,
    0x31, 0x8a, 0x60, 0x18, 0xf0, 0x3b, 0x73, 0xf5, 0xed, 0xe4, 0xd4, 0xd0,
    0x71, 0xf9, 0xde, 0x03, 0xfd, 0x7a, 0xea, 0x10, 0x5d, 0x92, 0x99, 0xb8,
    0xaf, 0x99, 0xaa, 0x07, 0x5b, 0xdb, 0x4d, 0xb9, 0xaa, 0x28, 0xc1, 0x8d,
    0x17, 0x4b, 0x56, 0xee, 0x2a, 0x01, 0x4d, 0x09, 0x88, 0x96, 0xff, 0x22,
    0x82, 0xc9, 0x55, 0xa8, 0x19, 0x69, 0xe0, 0x69, 0xfa, 0x8c, 0xe0, 0x07,
    0xa1, 0x80, 0x18, 0x3a, 0x07, 0xdf, 0xae, 0x17
};

const FLASH_QUALIFIER byte seedB_data[] = {
    0xa6, 0x5a, 0xd0, 0xf3, 0x45, 0xdb, 0x4e, 0x0e, 0xff, 0xe8, 0x75, 0xc3,
    0xa2, 0xe7, 0x1f, 0x42, 0xc7, 0x12, 0x9d, 0x62, 0x0f, 0xf5, 0xc1, 0x19,
    0xa9, 0xef, 0x55, 0xf0, 0x51, 0x85, 0xe0, 0xfb, /* nonce next */
    0x85, 0x81, 0xf9, 0x31, 0x75, 0x17, 0x27, 0x6e, 0x06, 0xe9, 0x60, 0x7d,
    0xdb, 0xcb, 0xcc, 0x2e
};

const FLASH_QUALIFIER byte outputB_data[] = {
    0xd3, 0xe1, 0x60, 0xc3, 0x5b, 0x99, 0xf3, 0x40, 0xb2, 0x62, 0x82, 0x64,
    0xd1, 0x75, 0x10, 0x60, 0xe0, 0x04, 0x5d, 0xa3, 0x83, 0xff, 0x57, 0xa5,
    0x7d, 0x73, 0xa6, 0x73, 0xd2, 0xb8, 0xd8, 0x0d, 0xaa, 0xf6, 0xa6, 0xc3,
    0x5a, 0x91, 0xbb, 0x45, 0x79, 0xd7, 0x3f, 0xd0, 0xc8, 0xfe, 0xd1, 0x11,
    0xb0, 0x39, 0x13, 0x06, 0x82, 0x8a, 0xdf, 0xed, 0x52, 0x8f, 0x01, 0x81,
    0x21, 0xb3, 0xfe, 0xbd, 0xc3, 0x43, 0xe7, 0x97, 0xb8, 0x7d, 0xbb, 0x63,
    0xdb, 0x13, 0x33, 0xde, 0xd9, 0xd1, 0xec, 0xe1, 0x77, 0xcf, 0xa6, 0xb7,
    0x1f, 0xe8, 0xab, 0x1d, 0xa4, 0x66, 0x24, 0xed, 0x64, 0x15, 0xe5, 0x1c,
    0xcd, 0xe2, 0xc7, 0xca, 0x86, 0xe2, 0x83, 0x99, 0x0e, 0xea, 0xeb, 0x91,
    0x12, 0x04, 0x15, 0x52, 0x8b, 0x22, 0x95, 0x91, 0x02, 0x81, 0xb0, 0x2d,
    0xd4, 0x31, 0xf4, 0xc9, 0xf7, 0x04, 0x27, 0xdf
};


/* SHA-512 DRBG KAT vectors for local health test.
 * Source: NIST CAVP Hash_DRBG.rsp, [SHA-512], PredictionResistance=False,
 * EntropyInputLen=256, NonceLen=128, PersonalizationStringLen=0,
 * AdditionalInputLen=0, ReturnedBitsLen=2048. */
#ifdef WOLFSSL_DRBG_SHA512

/* Reseed test vectors (COUNT=0 from reseed section) */
static const byte sha512_seedA_data[] = {
    /* EntropyInput (32 bytes) || Nonce (16 bytes) */
    0x31, 0x44, 0xe1, 0x7a, 0x10, 0xc8, 0x56, 0x12,
    0x97, 0x64, 0xf5, 0x8f, 0xd8, 0xe4, 0x23, 0x10,
    0x20, 0x54, 0x69, 0x96, 0xc0, 0xbf, 0x6c, 0xff,
    0x8e, 0x91, 0xc2, 0x4e, 0xe0, 0x9b, 0xe3, 0x33,
    0xb1, 0x6f, 0xcb, 0x1c, 0xf0, 0xc0, 0x10, 0xf3,
    0x1f, 0xea, 0xb7, 0x33, 0x58, 0x8b, 0x8e, 0x04
};
static const byte sha512_reseedSeedA_data[] = {
    /* EntropyInputReseed (32 bytes) */
    0xa0, 0xb3, 0x58, 0x4c, 0x2c, 0x84, 0x12, 0xf6,
    0x18, 0x40, 0x68, 0x34, 0x40, 0x4d, 0x1e, 0xb0,
    0xce, 0x99, 0x9b, 0xa2, 0x89, 0x66, 0x05, 0x4d,
    0x7e, 0x49, 0x7e, 0x0d, 0xb6, 0x08, 0xb9, 0x67
};
static const byte sha512_outputA_data[] = {
    0xef, 0xa3, 0x5d, 0xd0, 0x36, 0x2a, 0xdb, 0x76,
    0x26, 0x45, 0x6b, 0x36, 0xfa, 0xc7, 0x4d, 0x3c,
    0x28, 0xd0, 0x1d, 0x92, 0x64, 0x20, 0x27, 0x5a,
    0x28, 0xbe, 0xa9, 0xc9, 0xdd, 0x75, 0x47, 0xc1,
    0x5e, 0x79, 0x31, 0x85, 0x2a, 0xc1, 0x27, 0x70,
    0x76, 0x56, 0x75, 0x35, 0x23, 0x9c, 0x1f, 0x42,
    0x9c, 0x7f, 0x75, 0xcf, 0x74, 0xc2, 0x26, 0x7d,
    0xeb, 0x6a, 0x3e, 0x59, 0x6c, 0xf3, 0x26, 0x15,
    0x6c, 0x79, 0x69, 0x41, 0x28, 0x3b, 0x8d, 0x58,
    0x3f, 0x17, 0x1c, 0x2f, 0x6e, 0x33, 0x23, 0xf7,
    0x55, 0x5e, 0x1b, 0x18, 0x1f, 0xfd, 0xa3, 0x05,
    0x07, 0x21, 0x0c, 0xb1, 0xf5, 0x89, 0xb2, 0x3c,
    0xd7, 0x18, 0x80, 0xfd, 0x44, 0x37, 0x0c, 0xac,
    0xf4, 0x33, 0x75, 0xb0, 0xdb, 0x7e, 0x33, 0x6f,
    0x12, 0xb3, 0x09, 0xbf, 0xd4, 0xf6, 0x10, 0xbb,
    0x8f, 0x20, 0xe1, 0xa1, 0x5e, 0x25, 0x3a, 0x4f,
    0xe5, 0x11, 0xa0, 0x27, 0x96, 0x8d, 0xf0, 0xb1,
    0x05, 0xa1, 0xd7, 0x3a, 0xff, 0x7c, 0x7a, 0x82,
    0x6d, 0x39, 0xf6, 0x40, 0xdf, 0xb8, 0xf5, 0x22,
    0x25, 0x9e, 0xd4, 0x02, 0x28, 0x2e, 0x2c, 0x2e,
    0x9d, 0x3a, 0x49, 0x8f, 0x51, 0x72, 0x5f, 0xe4,
    0x14, 0x1b, 0x06, 0xda, 0x55, 0x98, 0xa4, 0x2a,
    0xc1, 0xe0, 0x49, 0x4e, 0x99, 0x7d, 0x56, 0x6a,
    0x1a, 0x39, 0xb6, 0x76, 0xb9, 0x6a, 0x60, 0x03,
    0xa4, 0xc5, 0xdb, 0x84, 0xf2, 0x46, 0x58, 0x4e,
    0xe6, 0x5a, 0xf7, 0x0f, 0xf2, 0x16, 0x02, 0x78,
    0x16, 0x6d, 0xa1, 0x6d, 0x91, 0xc9, 0xb8, 0xf2,
    0xde, 0xb0, 0x27, 0x51, 0xa1, 0x08, 0x8a, 0xd6,
    0xbe, 0x4e, 0x80, 0xef, 0x96, 0x6e, 0xb7, 0x3e,
    0x66, 0xbc, 0x87, 0xca, 0xd8, 0x7c, 0x77, 0xc0,
    0xb3, 0x4a, 0x21, 0xba, 0x1d, 0xa0, 0xba, 0x6d,
    0x16, 0xca, 0x50, 0x46, 0xdc, 0x4a, 0xbd, 0xa0
};

/* No-reseed test vectors (COUNT=0 from no-reseed section) */
static const byte sha512_seedB_data[] = {
    /* EntropyInput (32 bytes) || Nonce (16 bytes) */
    0x6b, 0x50, 0xa7, 0xd8, 0xf8, 0xa5, 0x5d, 0x7a,
    0x3d, 0xf8, 0xbb, 0x40, 0xbc, 0xc3, 0xb7, 0x22,
    0xd8, 0x70, 0x8d, 0xe6, 0x7f, 0xda, 0x01, 0x0b,
    0x03, 0xc4, 0xc8, 0x4d, 0x72, 0x09, 0x6f, 0x8c,
    0x3e, 0xc6, 0x49, 0xcc, 0x62, 0x56, 0xd9, 0xfa,
    0x31, 0xdb, 0x7a, 0x29, 0x04, 0xaa, 0xf0, 0x25
};
static const byte sha512_outputB_data[] = {
    0x95, 0xb7, 0xf1, 0x7e, 0x98, 0x02, 0xd3, 0x57,
    0x73, 0x92, 0xc6, 0xa9, 0xc0, 0x80, 0x83, 0xb6,
    0x7d, 0xd1, 0x29, 0x22, 0x65, 0xb5, 0xf4, 0x2d,
    0x23, 0x7f, 0x1c, 0x55, 0xbb, 0x9b, 0x10, 0xbf,
    0xcf, 0xd8, 0x2c, 0x77, 0xa3, 0x78, 0xb8, 0x26,
    0x6a, 0x00, 0x99, 0x14, 0x3b, 0x3c, 0x2d, 0x64,
    0x61, 0x1e, 0xee, 0xb6, 0x9a, 0xcd, 0xc0, 0x55,
    0x95, 0x7c, 0x13, 0x9e, 0x8b, 0x19, 0x0c, 0x7a,
    0x06, 0x95, 0x5f, 0x2c, 0x79, 0x7c, 0x27, 0x78,
    0xde, 0x94, 0x03, 0x96, 0xa5, 0x01, 0xf4, 0x0e,
    0x91, 0x39, 0x6a, 0xcf, 0x8d, 0x7e, 0x45, 0xeb,
    0xdb, 0xb5, 0x3b, 0xbf, 0x8c, 0x97, 0x52, 0x30,
    0xd2, 0xf0, 0xff, 0x91, 0x06, 0xc7, 0x61, 0x19,
    0xae, 0x49, 0x8e, 0x7f, 0xbc, 0x03, 0xd9, 0x0f,
    0x8e, 0x4c, 0x51, 0x62, 0x7a, 0xed, 0x5c, 0x8d,
    0x42, 0x63, 0xd5, 0xd2, 0xb9, 0x78, 0x87, 0x3a,
    0x0d, 0xe5, 0x96, 0xee, 0x6d, 0xc7, 0xf7, 0xc2,
    0x9e, 0x37, 0xee, 0xe8, 0xb3, 0x4c, 0x90, 0xdd,
    0x1c, 0xf6, 0xa9, 0xdd, 0xb2, 0x2b, 0x4c, 0xbd,
    0x08, 0x6b, 0x14, 0xb3, 0x5d, 0xe9, 0x3d, 0xa2,
    0xd5, 0xcb, 0x18, 0x06, 0x69, 0x8c, 0xbd, 0x7b,
    0xbb, 0x67, 0xbf, 0xe3, 0xd3, 0x1f, 0xd2, 0xd1,
    0xdb, 0xd2, 0xa1, 0xe0, 0x58, 0xa3, 0xeb, 0x99,
    0xd7, 0xe5, 0x1f, 0x1a, 0x93, 0x8e, 0xed, 0x5e,
    0x1c, 0x1d, 0xe2, 0x3a, 0x6b, 0x43, 0x45, 0xd3,
    0x19, 0x14, 0x09, 0xf9, 0x2f, 0x39, 0xb3, 0x67,
    0x0d, 0x8d, 0xbf, 0xb6, 0x35, 0xd8, 0xe6, 0xa3,
    0x69, 0x32, 0xd8, 0x10, 0x33, 0xd1, 0x44, 0x8d,
    0x63, 0xb4, 0x03, 0xdd, 0xf8, 0x8e, 0x12, 0x1b,
    0x6e, 0x81, 0x9a, 0xc3, 0x81, 0x22, 0x6c, 0x13,
    0x21, 0xe4, 0xb0, 0x86, 0x44, 0xf6, 0x72, 0x7c,
    0x36, 0x8c, 0x5a, 0x9f, 0x7a, 0x4b, 0x3e, 0xe2
};
#endif /* WOLFSSL_DRBG_SHA512 */


static int wc_RNG_HealthTestLocal(WC_RNG* rng, int reseed, void* heap,
                                  int devId)
{
    int ret = 0;

#ifdef WOLFSSL_DRBG_SHA512
    /* SHA-512 DRBG health test path */
    if (rng->drbgType == WC_DRBG_SHA512) {
    #ifdef WOLFSSL_SMALL_STACK_CACHE
        byte *check512 = rng->health_check_scratch_512;
        DRBG_SHA512_internal* drbg512 = rng->drbg512_scratch;
    #else
        WC_DECLARE_VAR(check512, byte, RNG_HEALTH_TEST_CHECK_SIZE_SHA512, 0);
        WC_DECLARE_VAR(drbg512, DRBG_SHA512_internal, 1, 0);

        WC_ALLOC_VAR_EX(check512, byte, RNG_HEALTH_TEST_CHECK_SIZE_SHA512,
            heap, DYNAMIC_TYPE_TMP_BUFFER, return MEMORY_E);
        WC_ALLOC_VAR_EX(drbg512, DRBG_SHA512_internal, 1, heap,
            DYNAMIC_TYPE_TMP_BUFFER, WC_DO_NOTHING);
        #ifdef WC_DECLARE_VAR_IS_HEAP_ALLOC
        if (drbg512 == NULL) {
            WC_FREE_VAR_EX(check512, heap, DYNAMIC_TYPE_TMP_BUFFER);
            return MEMORY_E;
        }
        #endif
    #endif

        if (reseed) {
            /* Reseed test with NIST CAVP SHA-512 vectors */
            ret = wc_RNG_HealthTest_SHA512_ex_internal(
                        drbg512, 1, NULL, 0, NULL, 0,
                        sha512_seedA_data, sizeof(sha512_seedA_data),
                        sha512_reseedSeedA_data,
                        sizeof(sha512_reseedSeedA_data),
                        NULL, 0, NULL, 0,
                        check512, RNG_HEALTH_TEST_CHECK_SIZE_SHA512,
                        heap, devId);
            if (ret == 0) {
                if (ConstantCompare(check512, sha512_outputA_data,
                                    RNG_HEALTH_TEST_CHECK_SIZE_SHA512) != 0)
                    ret = -1;
            }
        }
        else {
            /* No-reseed test with NIST CAVP SHA-512 vectors */
            ret = wc_RNG_HealthTest_SHA512_ex_internal(
                        drbg512, 0, NULL, 0, NULL, 0,
                        sha512_seedB_data, sizeof(sha512_seedB_data),
                        NULL, 0,
                        NULL, 0, NULL, 0,
                        check512, RNG_HEALTH_TEST_CHECK_SIZE_SHA512,
                        heap, devId);
            if (ret == 0) {
                if (ConstantCompare(check512, sha512_outputB_data,
                                    RNG_HEALTH_TEST_CHECK_SIZE_SHA512) != 0)
                    ret = -1;
            }
        }

    #ifndef WOLFSSL_SMALL_STACK_CACHE
        WC_FREE_VAR_EX(check512, heap, DYNAMIC_TYPE_TMP_BUFFER);
        WC_FREE_VAR_EX(drbg512, heap, DYNAMIC_TYPE_TMP_BUFFER);
    #endif
        return ret;
    }
#endif /* WOLFSSL_DRBG_SHA512 */

    /* SHA-256 DRBG health test path (original) */
#ifndef NO_SHA256
    {
#ifdef WOLFSSL_SMALL_STACK_CACHE
    byte *check = rng->health_check_scratch;
    DRBG_internal* drbg = (DRBG_internal *)rng->drbg_scratch;
#else
    WC_DECLARE_VAR(check, byte, RNG_HEALTH_TEST_CHECK_SIZE, 0);
    WC_DECLARE_VAR(drbg, DRBG_internal, 1, 0);

    (void)rng;

    WC_ALLOC_VAR_EX(check, byte, RNG_HEALTH_TEST_CHECK_SIZE, heap,
        DYNAMIC_TYPE_TMP_BUFFER, return MEMORY_E);
    WC_ALLOC_VAR_EX(drbg, DRBG_internal, 1, heap,
        DYNAMIC_TYPE_TMP_BUFFER, WC_DO_NOTHING);
    #ifdef WC_DECLARE_VAR_IS_HEAP_ALLOC
    if (drbg == NULL) {
        WC_FREE_VAR_EX(check, heap, DYNAMIC_TYPE_TMP_BUFFER);
        return MEMORY_E;
    }
    #endif
#endif

    if (reseed) {
#ifdef WOLFSSL_USE_FLASHMEM
        byte* seedA = (byte*)XMALLOC(sizeof(seedA_data), heap,
                             DYNAMIC_TYPE_TMP_BUFFER);
        byte* reseedSeedA = (byte*)XMALLOC(sizeof(reseedSeedA_data), heap,
                             DYNAMIC_TYPE_TMP_BUFFER);
        byte* outputA = (byte*)XMALLOC(sizeof(outputA_data), heap,
                             DYNAMIC_TYPE_TMP_BUFFER);

        if (!seedA || !reseedSeedA || !outputA) {
            XFREE(seedA, heap, DYNAMIC_TYPE_TMP_BUFFER);
            XFREE(reseedSeedA, heap, DYNAMIC_TYPE_TMP_BUFFER);
            XFREE(outputA, heap, DYNAMIC_TYPE_TMP_BUFFER);
            ret = MEMORY_E;
        }
        else {
            XMEMCPY_P(seedA, seedA_data, sizeof(seedA_data));
            XMEMCPY_P(reseedSeedA, reseedSeedA_data, sizeof(reseedSeedA_data));
            XMEMCPY_P(outputA, outputA_data, sizeof(outputA_data));
#else
        const byte* seedA = seedA_data;
        const byte* reseedSeedA = reseedSeedA_data;
        const byte* outputA = outputA_data;
#endif
        ret = wc_RNG_HealthTest_ex_internal(drbg, 1, NULL, 0,
                                   seedA, sizeof(seedA_data),
                                   reseedSeedA, sizeof(reseedSeedA_data),
                                   check, RNG_HEALTH_TEST_CHECK_SIZE,
                                   heap, devId);
        if (ret == 0) {
            if (ConstantCompare(check, outputA,
                                RNG_HEALTH_TEST_CHECK_SIZE) != 0)
                ret = -1;
        }

#ifdef WOLFSSL_USE_FLASHMEM
            XFREE(seedA, NULL, DYNAMIC_TYPE_TMP_BUFFER);
            XFREE(reseedSeedA, NULL, DYNAMIC_TYPE_TMP_BUFFER);
            XFREE(outputA, NULL, DYNAMIC_TYPE_TMP_BUFFER);
        }
#endif
    }
    else {
#ifdef WOLFSSL_USE_FLASHMEM
        byte* seedB = (byte*)XMALLOC(sizeof(seedB_data), heap,
                             DYNAMIC_TYPE_TMP_BUFFER);
        byte* outputB = (byte*)XMALLOC(sizeof(outputB_data), heap,
                               DYNAMIC_TYPE_TMP_BUFFER);

        if (!seedB || !outputB) {
            XFREE(seedB, heap, DYNAMIC_TYPE_TMP_BUFFER);
            XFREE(outputB, heap, DYNAMIC_TYPE_TMP_BUFFER);
            ret = MEMORY_E;
        }
        else {
            XMEMCPY_P(seedB, seedB_data, sizeof(seedB_data));
            XMEMCPY_P(outputB, outputB_data, sizeof(outputB_data));
#else
        const byte* seedB = seedB_data;
        const byte* outputB = outputB_data;
#endif
#if defined(DEBUG_WOLFSSL)
        WOLFSSL_MSG_EX("RNG_HEALTH_TEST_CHECK_SIZE = %d",
                        RNG_HEALTH_TEST_CHECK_SIZE);
        WOLFSSL_MSG_EX("sizeof(seedB_data)         = %d",
                        (int)sizeof(outputB_data));
#endif
        ret = wc_RNG_HealthTest_ex_internal(drbg, 0, NULL, 0,
                                   seedB, sizeof(seedB_data),
                                   NULL, 0,
                                   check, RNG_HEALTH_TEST_CHECK_SIZE,
                                   heap, devId);
        if (ret != 0) {
            #if defined(DEBUG_WOLFSSL)
            WOLFSSL_MSG_EX("RNG_HealthTest failed: err = %d", ret);
            #endif
        }
        else {
            ret = ConstantCompare(check, outputB,
                                RNG_HEALTH_TEST_CHECK_SIZE);
            if (ret != 0) {
                #if defined(DEBUG_WOLFSSL)
                WOLFSSL_MSG_EX("Random ConstantCompare failed: err = %d", ret);
                #endif
                ret = -1;
            }
        }

        /* The previous test cases use a large seed instead of a seed and nonce.
         * seedB is actually from a test case with a seed and nonce, and
         * just concatenates them. The pivot point between seed and nonce is
         * byte 32, feed them into the health test separately. */
        if (ret == 0) {
            ret = wc_RNG_HealthTest_ex_internal(drbg, 0,
                                       seedB + 32, sizeof(seedB_data) - 32,
                                       seedB, 32,
                                       NULL, 0,
                                       check, RNG_HEALTH_TEST_CHECK_SIZE,
                                       heap, devId);
            if (ret == 0) {
                if (ConstantCompare(check, outputB, sizeof(outputB_data)) != 0)
                    ret = -1;
            }
        }

#ifdef WOLFSSL_USE_FLASHMEM
            XFREE(seedB, heap, DYNAMIC_TYPE_TMP_BUFFER);
            XFREE(outputB, heap, DYNAMIC_TYPE_TMP_BUFFER);
        }
#endif
    }

#ifndef WOLFSSL_SMALL_STACK_CACHE
    WC_FREE_VAR_EX(check, heap, DYNAMIC_TYPE_TMP_BUFFER);
    WC_FREE_VAR_EX(drbg, heap, DYNAMIC_TYPE_TMP_BUFFER);
#endif
    } /* SHA-256 path */
#endif /* !NO_SHA256 */

    return ret;
}

/* ====================================================================== */
/* SHA-512 Health Test API                                                 */
/* ====================================================================== */
#ifdef WOLFSSL_DRBG_SHA512

static int wc_RNG_HealthTest_SHA512_ex_internal(DRBG_SHA512_internal* drbg,
                                  int reseed, const byte* nonce, word32 nonceSz,
                                  const byte* perso, word32 persoSz,
                                  const byte* seedA, word32 seedASz,
                                  const byte* seedB, word32 seedBSz,
                                  const byte* additionalA, word32 additionalASz,
                                  const byte* additionalB, word32 additionalBSz,
                                  byte* output, word32 outputSz,
                                  void* heap, int devId)
{
    int ret = -1;

    if (seedA == NULL || output == NULL) {
        return BAD_FUNC_ARG;
    }

    if (reseed != 0 && seedB == NULL) {
        return BAD_FUNC_ARG;
    }

    if (outputSz != RNG_HEALTH_TEST_CHECK_SIZE_SHA512) {
        return ret;
    }

#ifdef WOLFSSL_SMALL_STACK_CACHE
    (void)heap;
    (void)devId;

    if (Hash512_DRBG_Init(drbg, seedA, seedASz, nonce, nonceSz,
                          perso, persoSz) != 0) {
        goto exit_rng_ht512;
    }
#else
    if (Hash512_DRBG_Instantiate(drbg, seedA, seedASz, nonce, nonceSz,
                              perso, persoSz, heap, devId) != 0) {
        goto exit_rng_ht512;
    }
#endif

    if (reseed) {
        if (Hash512_DRBG_Reseed(drbg, seedB, seedBSz, NULL, 0) != 0) {
            goto exit_rng_ht512;
        }
    }

    /* First generate: output discarded per NIST DRBGVS procedure */
    if (Hash512_DRBG_Generate(drbg, output, outputSz,
                              additionalA, additionalASz) != 0) {
        goto exit_rng_ht512;
    }

    /* Second generate: this is the actual test output */
    if (Hash512_DRBG_Generate(drbg, output, outputSz,
                              additionalB, additionalBSz) != 0) {
        goto exit_rng_ht512;
    }

    ret = 0;

exit_rng_ht512:

#ifndef WOLFSSL_SMALL_STACK_CACHE
    if (Hash512_DRBG_Uninstantiate(drbg) != 0) {
        ret = -1;
    }
#endif

    return ret;
}


/* Extended API with personalization string and additional input
 * for ACVP testing */
int wc_RNG_HealthTest_SHA512_ex(int reseed,
                                const byte* nonce, word32 nonceSz,
                                const byte* persoString, word32 persoStringSz,
                                const byte* seedA, word32 seedASz,
                                const byte* seedB, word32 seedBSz,
                                const byte* additionalA, word32 additionalASz,
                                const byte* additionalB, word32 additionalBSz,
                                byte* output, word32 outputSz,
                                void* heap, int devId)
{
    int ret = -1;
    DRBG_SHA512_internal* drbg;
#ifndef WOLFSSL_SMALL_STACK
    DRBG_SHA512_internal  drbg_var;
#endif

    if (seedA == NULL || output == NULL) {
        return BAD_FUNC_ARG;
    }

    if (outputSz != RNG_HEALTH_TEST_CHECK_SIZE_SHA512) {
        return ret;
    }

#ifdef WOLFSSL_SMALL_STACK
    drbg = (DRBG_SHA512_internal*)XMALLOC(sizeof(DRBG_SHA512_internal), heap,
        DYNAMIC_TYPE_RNG);
    if (drbg == NULL) {
        return MEMORY_E;
    }
#else
    drbg = &drbg_var;
#endif

    /* SP 800-90A Sec 10.1.1.2: personalization string is concatenated
     * with entropy during instantiation via Hash_df. */
    ret = Hash512_DRBG_Instantiate(drbg, seedA, seedASz, nonce, nonceSz,
                                   persoString, persoStringSz, heap, devId);
    if (ret != 0) {
        goto exit_sha512_ex;
    }

    if (reseed) {
        if (seedB != NULL && seedBSz > 0) {
            ret = Hash512_DRBG_Reseed(drbg, seedB, seedBSz, NULL, 0);
            if (ret != 0) goto exit_sha512_ex;
        }
    }

    /* First generate (output discarded per NIST procedure) */
    ret = Hash512_DRBG_Generate(drbg, output, outputSz,
                                additionalA, additionalASz);
    if (ret != 0) goto exit_sha512_ex;

    /* Second generate (this is the actual output) */
    ret = Hash512_DRBG_Generate(drbg, output, outputSz,
                                additionalB, additionalBSz);

exit_sha512_ex:
    (void)Hash512_DRBG_Uninstantiate(drbg);

#ifdef WOLFSSL_SMALL_STACK
    XFREE(drbg, heap, DYNAMIC_TYPE_RNG);
#endif

    return (ret == DRBG_SUCCESS) ? 0 : -1;
}


/* Simple API matching wc_RNG_HealthTest() pattern - entropy+nonce only */
int wc_RNG_HealthTest_SHA512(int reseed,
                             const byte* seedA, word32 seedASz,
                             const byte* seedB, word32 seedBSz,
                             byte* output, word32 outputSz)
{
    int ret = -1;
    DRBG_SHA512_internal* drbg;
#ifndef WOLFSSL_SMALL_STACK
    DRBG_SHA512_internal  drbg_var;
#endif

#ifdef WOLFSSL_SMALL_STACK
    drbg = (DRBG_SHA512_internal*)XMALLOC(sizeof(DRBG_SHA512_internal), NULL,
        DYNAMIC_TYPE_RNG);
    if (drbg == NULL) {
        return MEMORY_E;
    }
#else
    drbg = &drbg_var;
#endif

#ifdef WOLFSSL_SMALL_STACK_CACHE
    ret = Hash512_DRBG_Instantiate(drbg,
                    NULL /* seed */, 0, NULL /* nonce */, 0,
                    NULL, 0, NULL, INVALID_DEVID);
    if (ret == 0)
#endif
    {
        ret = wc_RNG_HealthTest_SHA512_ex_internal(
                drbg, reseed, NULL, 0, NULL, 0,
                seedA, seedASz, seedB, seedBSz,
                NULL, 0, NULL, 0,
                output, outputSz, NULL, INVALID_DEVID);
#ifdef WOLFSSL_SMALL_STACK_CACHE
        Hash512_DRBG_Uninstantiate(drbg);
#endif
    }
    WC_FREE_VAR_EX(drbg, NULL, DYNAMIC_TYPE_RNG);

    return ret;
}

#endif /* WOLFSSL_DRBG_SHA512 */

#ifndef NO_SHA256
/* Extended SHA-256 Hash_DRBG health test per SP 800-90A.
 * Supports flexible output sizes, prediction resistance, personalization
 * strings, and additional input.
 *
 * predResistance=0: Instantiate(entropyA, nonce, perso) ->
 *                   Reseed(entropyB, additionalReseed) ->
 *                   Gen1(additionalA, discard) -> Gen2(additionalB, keep)
 * predResistance=1: Instantiate(entropyA, nonce, perso) ->
 *                   Reseed(entropyB, additionalA)+Gen1(NULL, discard) ->
 *                   Reseed(entropyC, additionalB)+Gen2(NULL, keep)
 */
int wc_RNG_HealthTest_SHA256_ex(
    int predResistance,
    const byte* nonce, word32 nonceSz,
    const byte* persoString, word32 persoStringSz,
    const byte* entropyA, word32 entropyASz,
    const byte* entropyB, word32 entropyBSz,
    const byte* entropyC, word32 entropyCsz,
    const byte* additionalA, word32 additionalASz,
    const byte* additionalB, word32 additionalBSz,
    const byte* additionalReseed, word32 additionalReseedSz,
    byte* output, word32 outputSz,
    void* heap, int devId)
{
    int ret;
    DRBG_internal* drbg;
#ifndef WOLFSSL_SMALL_STACK
    DRBG_internal  drbg_var;
#endif

    if (entropyA == NULL || output == NULL || outputSz == 0) {
        return BAD_FUNC_ARG;
    }

#ifdef WOLFSSL_SMALL_STACK
    drbg = (DRBG_internal*)XMALLOC(sizeof(DRBG_internal), heap,
        DYNAMIC_TYPE_RNG);
    if (drbg == NULL) {
        return MEMORY_E;
    }
#else
    drbg = &drbg_var;
#endif

    /* Instantiate with entropy, nonce, personalization string */
    ret = Hash_DRBG_Instantiate(drbg, entropyA, entropyASz, nonce, nonceSz,
                                persoString, persoStringSz, heap, devId);
    if (ret != 0) goto exit_sha256_ex;

    if (predResistance) {
        /* Prediction resistance mode per SP 800-90A 9.3.1:
         * additional_input is passed to Reseed, Generate gets NULL */

        /* Reseed 1 with additionalA, then Generate 1 with NULL (discard) */
        if (entropyB != NULL && entropyBSz > 0) {
            ret = Hash_DRBG_Reseed(drbg, entropyB, entropyBSz,
                                   additionalA, additionalASz);
            if (ret != 0) goto exit_sha256_ex;
        }
        ret = Hash_DRBG_Generate(drbg, output, outputSz, NULL, 0);
        if (ret != 0) goto exit_sha256_ex;

        /* Reseed 2 with additionalB, then Generate 2 with NULL (keep) */
        if (entropyC != NULL && entropyCsz > 0) {
            ret = Hash_DRBG_Reseed(drbg, entropyC, entropyCsz,
                                   additionalB, additionalBSz);
            if (ret != 0) goto exit_sha256_ex;
        }
        ret = Hash_DRBG_Generate(drbg, output, outputSz, NULL, 0);
    }
    else {
        /* Standard mode: explicit reseed, then two generates */
        if (entropyB != NULL && entropyBSz > 0) {
            ret = Hash_DRBG_Reseed(drbg, entropyB, entropyBSz,
                                   additionalReseed, additionalReseedSz);
            if (ret != 0) goto exit_sha256_ex;
        }

        /* Generate 1 (output discarded per NIST DRBGVS procedure) */
        ret = Hash_DRBG_Generate(drbg, output, outputSz,
                                 additionalA, additionalASz);
        if (ret != 0) goto exit_sha256_ex;

        /* Generate 2 (this is the actual test output) */
        ret = Hash_DRBG_Generate(drbg, output, outputSz,
                                 additionalB, additionalBSz);
    }

exit_sha256_ex:
    (void)Hash_DRBG_Uninstantiate(drbg);

#ifdef WOLFSSL_SMALL_STACK
    XFREE(drbg, heap, DYNAMIC_TYPE_RNG);
#endif

    return ret;
}
#endif /* !NO_SHA256 */


#ifdef WOLFSSL_DRBG_SHA512
/* Extended SHA-512 Hash_DRBG health test per SP 800-90A.
 * Supports flexible output sizes and prediction resistance mode.
 *
 * Per SP 800-90A Section 9.3.1, when prediction resistance is requested,
 * the additional_input is consumed by the Reseed step and the subsequent
 * Generate uses NULL additional_input.
 *
 * predResistance=0: Instantiate ->
 *                   Reseed(entropyB, additionalReseed) ->
 *                   Gen1(additionalA, discard) -> Gen2(additionalB, keep)
 * predResistance=1: Instantiate ->
 *                   Reseed(entropyB, additionalA)+Gen1(NULL, discard) ->
 *                   Reseed(entropyC, additionalB)+Gen2(NULL, keep)
 */
int wc_RNG_HealthTest_SHA512_ex2(
    int predResistance,
    const byte* nonce, word32 nonceSz,
    const byte* persoString, word32 persoStringSz,
    const byte* entropyA, word32 entropyASz,
    const byte* entropyB, word32 entropyBSz,
    const byte* entropyC, word32 entropyCsz,
    const byte* additionalA, word32 additionalASz,
    const byte* additionalB, word32 additionalBSz,
    const byte* additionalReseed, word32 additionalReseedSz,
    byte* output, word32 outputSz,
    void* heap, int devId)
{
    int ret;
    DRBG_SHA512_internal* drbg;
#ifndef WOLFSSL_SMALL_STACK
    DRBG_SHA512_internal  drbg_var;
#endif

    if (entropyA == NULL || output == NULL || outputSz == 0) {
        return BAD_FUNC_ARG;
    }

#ifdef WOLFSSL_SMALL_STACK
    drbg = (DRBG_SHA512_internal*)XMALLOC(sizeof(DRBG_SHA512_internal), heap,
        DYNAMIC_TYPE_RNG);
    if (drbg == NULL) {
        return MEMORY_E;
    }
#else
    drbg = &drbg_var;
#endif

    /* Instantiate with entropy, nonce, personalization string */
    ret = Hash512_DRBG_Instantiate(drbg, entropyA, entropyASz, nonce, nonceSz,
                                   persoString, persoStringSz, heap, devId);
    if (ret != 0) goto exit_sha512_ex2;

    if (predResistance) {
        /* Prediction resistance mode per SP 800-90A 9.3.1:
         * additional_input is passed to Reseed, Generate gets NULL */

        /* Reseed 1 with additionalA, then Generate 1 with NULL (discard) */
        if (entropyB != NULL && entropyBSz > 0) {
            ret = Hash512_DRBG_Reseed(drbg, entropyB, entropyBSz,
                                      additionalA, additionalASz);
            if (ret != 0) goto exit_sha512_ex2;
        }
        ret = Hash512_DRBG_Generate(drbg, output, outputSz, NULL, 0);
        if (ret != 0) goto exit_sha512_ex2;

        /* Reseed 2 with additionalB, then Generate 2 with NULL (keep) */
        if (entropyC != NULL && entropyCsz > 0) {
            ret = Hash512_DRBG_Reseed(drbg, entropyC, entropyCsz,
                                      additionalB, additionalBSz);
            if (ret != 0) goto exit_sha512_ex2;
        }
        ret = Hash512_DRBG_Generate(drbg, output, outputSz, NULL, 0);
    }
    else {
        /* Standard mode: explicit reseed, then two generates */
        if (entropyB != NULL && entropyBSz > 0) {
            ret = Hash512_DRBG_Reseed(drbg, entropyB, entropyBSz,
                                      additionalReseed, additionalReseedSz);
            if (ret != 0) goto exit_sha512_ex2;
        }

        /* Generate 1 (output discarded per NIST DRBGVS procedure) */
        ret = Hash512_DRBG_Generate(drbg, output, outputSz,
                                    additionalA, additionalASz);
        if (ret != 0) goto exit_sha512_ex2;

        /* Generate 2 (this is the actual test output) */
        ret = Hash512_DRBG_Generate(drbg, output, outputSz,
                                    additionalB, additionalBSz);
    }

exit_sha512_ex2:
    (void)Hash512_DRBG_Uninstantiate(drbg);

#ifdef WOLFSSL_SMALL_STACK
    XFREE(drbg, heap, DYNAMIC_TYPE_RNG);
#endif

    return (ret == DRBG_SUCCESS) ? 0 : -1;
}

#endif /* WOLFSSL_DRBG_SHA512 */

#endif /* HAVE_HASHDRBG */


#ifdef HAVE_WNR

/*
 * Init global Whitewood netRandom context
 * Returns 0 on success, negative on error
 */
int wc_InitNetRandom(const char* configFile, wnr_hmac_key hmac_cb, int timeout)
{
    int ret;

    if (configFile == NULL || timeout < 0)
        return BAD_FUNC_ARG;

#ifndef WOLFSSL_MUTEX_INITIALIZER
    if (wnr_mutex_inited > 0) {
        WOLFSSL_MSG("netRandom context already created, skipping");
        return 0;
    }

    if (wc_InitMutex(&wnr_mutex) != 0) {
        WOLFSSL_MSG("Bad Init Mutex wnr_mutex");
        return BAD_MUTEX_E;
    }

    wnr_mutex_inited = 1;
#endif

    if (wnr_inited > 0) {
        WOLFSSL_MSG("netRandom context already created, skipping");
        return 0;
    }

    if (wc_LockMutex(&wnr_mutex) != 0) {
        WOLFSSL_MSG("Bad Lock Mutex wnr_mutex");
        return BAD_MUTEX_E;
    }

    /* store entropy timeout */
    wnr_timeout = timeout;

    /* create global wnr_context struct */
    if (wnr_create(&wnr_ctx) != WNR_ERROR_NONE) {
        WOLFSSL_MSG("Error creating global netRandom context");
        ret = RNG_FAILURE_E;
        goto out;
    }

    /* load config file */
    if (wnr_config_loadf(wnr_ctx, (char*)configFile) != WNR_ERROR_NONE) {
        WOLFSSL_MSG("Error loading config file into netRandom context");
        wnr_destroy(wnr_ctx);
        wnr_ctx = NULL;
        ret = RNG_FAILURE_E;
        goto out;
    }

    /* create/init polling mechanism */
    if (wnr_poll_create() != WNR_ERROR_NONE) {
        WOLFSSL_MSG("Error initializing netRandom polling mechanism");
        wnr_destroy(wnr_ctx);
        wnr_ctx = NULL;
        ret = RNG_FAILURE_E;
        goto out;
    }

    /* validate config, set HMAC callback (optional) */
    if (wnr_setup(wnr_ctx, hmac_cb) != WNR_ERROR_NONE) {
        WOLFSSL_MSG("Error setting up netRandom context");
        wnr_destroy(wnr_ctx);
        wnr_ctx = NULL;
        wnr_poll_destroy();
        ret = RNG_FAILURE_E;
        goto out;
    }

    wnr_inited = 1;

out:

    wc_UnLockMutex(&wnr_mutex);

    return ret;
}

/*
 * Free global Whitewood netRandom context
 * Returns 0 on success, negative on error
 */
int wc_FreeNetRandom(void)
{
    if (wnr_inited > 0) {

        if (wc_LockMutex(&wnr_mutex) != 0) {
            WOLFSSL_MSG("Bad Lock Mutex wnr_mutex");
            return BAD_MUTEX_E;
        }

        if (wnr_ctx != NULL) {
            wnr_destroy(wnr_ctx);
            wnr_ctx = NULL;
        }
        wnr_poll_destroy();

        wc_UnLockMutex(&wnr_mutex);

#ifndef WOLFSSL_MUTEX_INITIALIZER
        wc_FreeMutex(&wnr_mutex);
        wnr_mutex_inited = 0;
#endif

        wnr_inited = 0;
    }

    return 0;
}

#endif /* HAVE_WNR */


#if defined(HAVE_INTEL_RDRAND) || defined(HAVE_INTEL_RDSEED) || \
    defined(HAVE_AMD_RDSEED)

#ifdef WOLFSSL_ASYNC_CRYPT
    /* need more retries if multiple cores */
    #define INTELRD_RETRY (32 * 8)
#else
    #define INTELRD_RETRY 32
#endif

#if defined(HAVE_INTEL_RDSEED) || defined(HAVE_AMD_RDSEED)

#ifndef USE_INTEL_INTRINSICS

    /* return 0 on success */
    static WC_INLINE int IntelRDseed64(word64* seed)
    {
        unsigned char ok;

        __asm__ volatile("rdseed %0; setc %1":"=r"(*seed), "=qm"(ok));
        return (ok) ? 0 : -1;
    }

#else /* USE_INTEL_INTRINSICS */
    /* The compiler Visual Studio uses does not allow inline assembly.
     * It does allow for Intel intrinsic functions. */

    /* return 0 on success */
# ifdef __GNUC__
    __attribute__((target("rdseed")))
# endif
    static WC_INLINE int IntelRDseed64(word64* seed)
    {
        int ok;

        ok = _rdseed64_step((unsigned long long*) seed);
        return (ok) ? 0 : -1;
    }

#endif /* USE_INTEL_INTRINSICS */

/* return 0 on success */
static WC_INLINE int IntelRDseed64_r(word64* rnd)
{
    int i;
    for (i = 0; i < INTELRD_RETRY; i++) {
        if (IntelRDseed64(rnd) == 0)
            return 0;
    }
    return -1;
}

/* return 0 on success */
static int wc_GenerateSeed_IntelRD(OS_Seed* os, byte* output, word32 sz)
{
    int ret;
    word64 rndTmp;
    static int rdseed_sanity_status = 0;

    (void)os;

    if (!IS_INTEL_RDSEED(intel_flags))
        return -1;

    /* Note, access to rdseed_sanity_status is benignly racey on multithreaded
     * targets.
     */
    if (rdseed_sanity_status == 0) {
        word64 sanity_word1 = 0, sanity_word2 = 0;

        ret = IntelRDseed64_r(&sanity_word1);
        if (ret != 0)
            return ret;

        ret = IntelRDseed64_r(&sanity_word2);
        if (ret != 0)
            return ret;

        if (sanity_word1 == sanity_word2) {
            ret = IntelRDseed64_r(&sanity_word1);
            if (ret != 0)
                return ret;

            if (sanity_word1 == sanity_word2) {
#ifdef WC_VERBOSE_RNG
                WOLFSSL_DEBUG_PRINTF(
                    "WARNING: disabling RDSEED due to repeating word 0x%lx -- "
                    "check CPU microcode version.", sanity_word2);
#endif
                rdseed_sanity_status = -1;
                return -1;
            }
        }

        rdseed_sanity_status = 1;
    }
    else if (rdseed_sanity_status < 0) {
        return -1;
    }

    for (; (sz / sizeof(word64)) > 0; sz -= sizeof(word64),
                                                    output += sizeof(word64)) {
        ret = IntelRDseed64_r((word64*)output);
        if (ret != 0)
            return ret;
    }
    if (sz == 0)
        return 0;

    /* handle unaligned remainder */
    ret = IntelRDseed64_r(&rndTmp);
    if (ret != 0)
        return ret;

    XMEMCPY(output, &rndTmp, sz);
    ForceZero(&rndTmp, sizeof(rndTmp));

    return 0;
}

#endif /* HAVE_INTEL_RDSEED || HAVE_AMD_RDSEED */

#ifdef HAVE_INTEL_RDRAND

#ifndef USE_INTEL_INTRINSICS

/* return 0 on success */
static WC_INLINE int IntelRDrand64(word64 *rnd)
{
    unsigned char ok;

    __asm__ volatile("rdrand %0; setc %1":"=r"(*rnd), "=qm"(ok));

    return (ok) ? 0 : -1;
}

#else /* USE_INTEL_INTRINSICS */
    /* The compiler Visual Studio uses does not allow inline assembly.
     * It does allow for Intel intrinsic functions. */

/* return 0 on success */
# ifdef __GNUC__
__attribute__((target("rdrnd")))
# endif
static WC_INLINE int IntelRDrand64(word64 *rnd)
{
    int ok;

    ok = _rdrand64_step((unsigned long long*) rnd);

    return (ok) ? 0 : -1;
}

#endif /* USE_INTEL_INTRINSICS */

/* return 0 on success */
static WC_INLINE int IntelRDrand64_r(word64 *rnd)
{
    int i;
    for (i = 0; i < INTELRD_RETRY; i++) {
        if (IntelRDrand64(rnd) == 0)
            return 0;
    }
    return -1;
}

/* return 0 on success */
static int wc_GenerateRand_IntelRD(OS_Seed* os, byte* output, word32 sz)
{
    int ret;
    word64 rndTmp;

    (void)os;

    if (!IS_INTEL_RDRAND(intel_flags))
        return -1;

    for (; (sz / sizeof(word64)) > 0; sz -= sizeof(word64),
                                                    output += sizeof(word64)) {
        ret = IntelRDrand64_r((word64 *)output);
        if (ret != 0)
            return ret;
    }
    if (sz == 0)
        return 0;

    /* handle unaligned remainder */
    ret = IntelRDrand64_r(&rndTmp);
    if (ret != 0)
        return ret;

    XMEMCPY(output, &rndTmp, sz);

    return 0;
}

#endif /* HAVE_INTEL_RDRAND */
#endif /* HAVE_INTEL_RDRAND || HAVE_INTEL_RDSEED || HAVE_AMD_RDSEED */


/* Begin wc_GenerateSeed Implementations */
#if defined(CUSTOM_RAND_GENERATE_SEED)

    /* Implement your own random generation function
     * Return 0 to indicate success
     * int rand_gen_seed(byte* output, word32 sz);
     * #define CUSTOM_RAND_GENERATE_SEED  rand_gen_seed */

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        (void)os; /* Suppress unused arg warning */
        return CUSTOM_RAND_GENERATE_SEED(output, sz);
    }

#elif defined(CUSTOM_RAND_GENERATE_SEED_OS)

    /* Implement your own random generation function,
     *  which includes OS_Seed.
     * Return 0 to indicate success
     * int rand_gen_seed(OS_Seed* os, byte* output, word32 sz);
     * #define CUSTOM_RAND_GENERATE_SEED_OS  rand_gen_seed */

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        return CUSTOM_RAND_GENERATE_SEED_OS(os, output, sz);
    }

#elif defined(CUSTOM_RAND_GENERATE)

   /* Implement your own random generation function
    * word32 rand_gen(void);
    * #define CUSTOM_RAND_GENERATE  rand_gen  */

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        word32 i = 0;

        (void)os;

        while (i < sz)
        {
            /* If not aligned or there is odd/remainder */
            if( (i + sizeof(CUSTOM_RAND_TYPE)) > sz ||
                ((wc_ptr_t)&output[i] % sizeof(CUSTOM_RAND_TYPE)) != 0
            ) {
                /* Single byte at a time */
                output[i++] = (byte)CUSTOM_RAND_GENERATE();
            }
            else {
                /* Use native 8, 16, 32 or 64 copy instruction */
                *((CUSTOM_RAND_TYPE*)&output[i]) = CUSTOM_RAND_GENERATE();
                i += sizeof(CUSTOM_RAND_TYPE);
            }
        }

        return 0;
    }

#elif defined(WOLFSSL_SGX)

int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
{
    int ret = !SGX_SUCCESS;
    int i, read_max = 10;

    for (i = 0; i < read_max && ret != SGX_SUCCESS; i++) {
        ret = sgx_read_rand(output, sz);
    }

    (void)os;
    return (ret == SGX_SUCCESS) ? 0 : 1;
}

#elif defined(USE_WINDOWS_API)

#ifdef WIN_REUSE_CRYPT_HANDLE
/* shared crypt handle for RNG use */
static ProviderHandle gHandle = 0;

int wc_WinCryptHandleInit(void)
{
    int ret = 0;
    if (gHandle == 0) {
        if(!CryptAcquireContext(&gHandle, 0, 0, PROV_RSA_FULL,
                                        CRYPT_VERIFYCONTEXT)) {
            DWORD dw = GetLastError();
            WOLFSSL_MSG("CryptAcquireContext failed!");
            WOLFSSL_ERROR((int)dw);
            ret = WINCRYPT_E;
        }
    }
    return ret;
}

void wc_WinCryptHandleCleanup(void)
{
    if (gHandle != 0) {
        CryptReleaseContext(gHandle, 0);
        gHandle = 0;
    }
}
#endif /* WIN_REUSE_CRYPT_HANDLE */

int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
{
#ifdef WOLF_CRYPTO_CB
    int ret;

    if (os != NULL
    #ifndef WOLF_CRYPTO_CB_FIND
        && os->devId != INVALID_DEVID)
    #endif
    {
        ret = wc_CryptoCb_RandomSeed(os, output, sz);
        if (ret != WC_NO_ERR_TRACE(CRYPTOCB_UNAVAILABLE))
            return ret;
        /* fall-through when unavailable */
    }
#endif

    #ifdef HAVE_INTEL_RDSEED
        if (IS_INTEL_RDSEED(intel_flags)) {
             if (!wc_GenerateSeed_IntelRD(NULL, output, sz)) {
                 /* success, we're done */
                 return 0;
             }
        #ifdef FORCE_FAILURE_RDSEED
             /* don't fall back to CryptoAPI */
             return READ_RAN_E;
        #endif
        }
    #endif /* HAVE_INTEL_RDSEED */

#ifdef WIN_REUSE_CRYPT_HANDLE
    /* Check that handle was initialized.
     * Note: initialization should be done through:
     * wolfSSL_Init -> wolfCrypt_Init -> wc_WinCryptHandleInit
     */
    if (wc_WinCryptHandleInit() != 0) {
        return WINCRYPT_E;
    }
    if (!CryptGenRandom(gHandle, sz, output))
        return CRYPTGEN_E;
#else
    if (!CryptAcquireContext(&os->handle, 0, 0, PROV_RSA_FULL,
                            CRYPT_VERIFYCONTEXT)) {
        return WINCRYPT_E;
    }
    if (!CryptGenRandom(os->handle, sz, output)) {
        return CRYPTGEN_E;
    }
    CryptReleaseContext(os->handle, 0);
    os->handle = 0;
#endif

    return 0;
}


#elif defined(HAVE_RTP_SYS) || defined(EBSNET)

#include "rtprand.h"   /* rtp_rand () */

#if (defined(HAVE_RTP_SYS) || (defined(RTPLATFORM) && (RTPLATFORM != 0)))
#include "rtptime.h"   /* rtp_get_system_msec() */

int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
{
    word32 i;

    rtp_srand(rtp_get_system_msec());
    for (i = 0; i < sz; i++ ) {
        output[i] = rtp_rand() % 256;
    }

    return 0;
}
#else
int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
{
    word32 i;
    KS_SEED(ks_get_ticks());

    for (i = 0; i < sz; i++ ) {
        output[i] = KS_RANDOM() % 256;
    }

    return 0;
}
#endif /* defined(HAVE_RTP_SYS) || (defined(RTPLATFORM) && (RTPLATFORM != 0)) */

#elif (defined(WOLFSSL_ATMEL) || defined(WOLFSSL_ATECC_RNG)) && \
      !defined(WOLFSSL_PIC32MZ_RNG)
    /* enable ATECC RNG unless using PIC32MZ one instead */
    #include <wolfssl/wolfcrypt/port/atmel/atmel.h>

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        int ret = 0;

        (void)os;
        if (output == NULL) {
            return BUFFER_E;
        }

        ret = atmel_get_random_number(sz, output);

        return ret;
    }

#elif defined(MICROCHIP_PIC32) || defined(MICROCHIP_MPLAB_HARMONY)

    #ifdef MICROCHIP_MPLAB_HARMONY
        #ifdef MICROCHIP_MPLAB_HARMONY_3
            #include "system/time/sys_time.h"
            #define PIC32_SEED_COUNT SYS_TIME_CounterGet
        #else
            #define PIC32_SEED_COUNT _CP0_GET_COUNT
        #endif
    #else
        #if !defined(WOLFSSL_MICROCHIP_PIC32MZ)
            #include <peripheral/timer.h>
        #endif
        extern word32 ReadCoreTimer(void);
        #define PIC32_SEED_COUNT ReadCoreTimer
    #endif

    #ifdef WOLFSSL_PIC32MZ_RNG
        #include "xc.h"
        int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
        {
            int i;
            byte rnd[8];
            word32 *rnd32 = (word32 *)rnd;
            word32 size = sz;
            byte* op = output;

#if ((__PIC32_FEATURE_SET0 == 'E') && (__PIC32_FEATURE_SET1 == 'C'))
            RNGNUMGEN1 = _CP0_GET_COUNT();
            RNGPOLY1 = _CP0_GET_COUNT();
            RNGPOLY2 = _CP0_GET_COUNT();
            RNGNUMGEN2 = _CP0_GET_COUNT();
#else
            /* All others can be seeded from the TRNG */
            RNGCONbits.TRNGMODE = 1;
            RNGCONbits.TRNGEN = 1;
            while (RNGCNT < 64);
            RNGCONbits.LOAD = 1;
            while (RNGCONbits.LOAD == 1);
            while (RNGCNT < 64);
            RNGPOLY2 = RNGSEED2;
            RNGPOLY1 = RNGSEED1;
#endif

            RNGCONbits.PLEN = 0x40;
            RNGCONbits.PRNGEN = 1;
            for (i=0; i<5; i++) { /* wait for RNGNUMGEN ready */
                volatile int x, y;
                x = RNGNUMGEN1;
                y = RNGNUMGEN2;
                (void)x;
                (void)y;
            }
            do {
                rnd32[0] = RNGNUMGEN1;
                rnd32[1] = RNGNUMGEN2;

                for(i=0; i<8; i++, op++) {
                    *op = rnd[i];
                    size --;
                    if(size==0)break;
                }
            } while(size);
            return 0;
        }
    #else  /* WOLFSSL_PIC32MZ_RNG */
        /* uses the core timer, in nanoseconds to seed srand */
        int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
        {
            int i;
            srand(PIC32_SEED_COUNT() * 25);

            for (i = 0; i < sz; i++ ) {
                output[i] = rand() % 256;
                if ( (i % 8) == 7)
                    srand(PIC32_SEED_COUNT() * 25);
            }
            return 0;
        }
    #endif /* WOLFSSL_PIC32MZ_RNG */

#elif defined(FREESCALE_K70_RNGA) || defined(FREESCALE_RNGA)
    /*
     * wc_Generates a RNG seed using the Random Number Generator Accelerator
     * on the Kinetis K70. Documentation located in Chapter 37 of
     * K70 Sub-Family Reference Manual (see Note 3 in the README for link).
     */
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        word32 i;

        /* turn on RNGA module */
        #if defined(SIM_SCGC3_RNGA_MASK)
            SIM_SCGC3 |= SIM_SCGC3_RNGA_MASK;
        #endif
        #if defined(SIM_SCGC6_RNGA_MASK)
            /* additionally needed for at least K64F */
            SIM_SCGC6 |= SIM_SCGC6_RNGA_MASK;
        #endif

        /* set SLP bit to 0 - "RNGA is not in sleep mode" */
        RNG_CR &= ~RNG_CR_SLP_MASK;

        /* set HA bit to 1 - "security violations masked" */
        RNG_CR |= RNG_CR_HA_MASK;

        /* set GO bit to 1 - "output register loaded with data" */
        RNG_CR |= RNG_CR_GO_MASK;

        for (i = 0; i < sz; i++) {

            /* wait for RNG FIFO to be full */
            while((RNG_SR & RNG_SR_OREG_LVL(0xF)) == 0) {}

            /* get value */
            output[i] = RNG_OR;
        }

        return 0;
    }

#elif defined(FREESCALE_K53_RNGB) || defined(FREESCALE_RNGB)
    /*
     * wc_Generates a RNG seed using the Random Number Generator (RNGB)
     * on the Kinetis K53. Documentation located in Chapter 33 of
     * K53 Sub-Family Reference Manual (see note in the README for link).
     */
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        int i;

        /* turn on RNGB module */
        SIM_SCGC3 |= SIM_SCGC3_RNGB_MASK;

        /* reset RNGB */
        RNG_CMD |= RNG_CMD_SR_MASK;

        /* FIFO generate interrupt, return all zeros on underflow,
         * set auto reseed */
        RNG_CR |= (RNG_CR_FUFMOD_MASK | RNG_CR_AR_MASK);

        /* gen seed, clear interrupts, clear errors */
        RNG_CMD |= (RNG_CMD_GS_MASK | RNG_CMD_CI_MASK | RNG_CMD_CE_MASK);

        /* wait for seeding to complete */
        while ((RNG_SR & RNG_SR_SDN_MASK) == 0) {}

        for (i = 0; i < sz; i++) {

            /* wait for a word to be available from FIFO */
            while((RNG_SR & RNG_SR_FIFO_LVL_MASK) == 0) {}

            /* get value */
            output[i] = RNG_OUT;
        }

        return 0;
    }

#elif defined(FREESCALE_KSDK_2_0_TRNG)
    #ifndef TRNG0
    #define TRNG0 TRNG
    #endif

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        status_t status;
        status = TRNG_GetRandomData(TRNG0, output, sz);
        (void)os;
        if (status == kStatus_Success)
        {
            return(0);
        }
        return RAN_BLOCK_E;
    }

#elif defined(FREESCALE_KSDK_2_0_RNGA)

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        status_t status;
        status = RNGA_GetRandomData(RNG, output, sz);
        (void)os;
        if (status == kStatus_Success)
        {
            return(0);
        }
        return RAN_BLOCK_E;
    }


#elif defined(FREESCALE_RNGA)

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        status_t status;
        status = RNGA_GetRandomData(RNG, output, sz);
        (void)os;
        if (status == kStatus_Success)
        {
            return(0);
        }
        return RAN_BLOCK_E;
    }
#elif !defined(WOLFSSL_CAAM) && \
    (defined(FREESCALE_MQX) || defined(FREESCALE_KSDK_MQX) || \
     defined(FREESCALE_KSDK_BM) || defined(FREESCALE_FREE_RTOS))
    /*
     * Fallback to USE_TEST_GENSEED if a FREESCALE platform did not match any
     * of the TRNG/RNGA/RNGB support
     */
    #define USE_TEST_GENSEED

#elif defined(WOLFSSL_SILABS_SE_ACCEL)
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        (void)os;
        return silabs_GenerateRand(output, sz);
    }

#elif defined(STM32_RNG)
     /* Generate a RNG seed using the hardware random number generator
      * on the STM32F2/F4/F7/L4. */

    #ifdef WOLFSSL_STM32_CUBEMX
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        int ret;
        RNG_HandleTypeDef hrng;
        word32 i = 0;
        (void)os;

        ret = wolfSSL_CryptHwMutexLock();
        if (ret != 0) {
            return ret;
        }

        /* enable RNG clock source */
        __HAL_RCC_RNG_CLK_ENABLE();

        /* enable RNG peripheral */
        XMEMSET(&hrng, 0, sizeof(hrng));
        hrng.Instance = RNG;
        HAL_RNG_Init(&hrng);

        while (i < sz) {
            /* If not aligned or there is odd/remainder */
            if( (i + sizeof(word32)) > sz ||
                ((wc_ptr_t)&output[i] % sizeof(word32)) != 0
            ) {
                /* Single byte at a time */
                uint32_t tmpRng = 0;
                if (HAL_RNG_GenerateRandomNumber(&hrng, &tmpRng) != HAL_OK) {
                    wolfSSL_CryptHwMutexUnLock();
                    return RAN_BLOCK_E;
                }
                output[i++] = (byte)tmpRng;
            }
            else {
                /* Use native 32 instruction */
                if (HAL_RNG_GenerateRandomNumber(&hrng, (uint32_t*)&output[i]) != HAL_OK) {
                    wolfSSL_CryptHwMutexUnLock();
                    return RAN_BLOCK_E;
                }
                i += sizeof(word32);
            }
        }

        HAL_RNG_DeInit(&hrng);

        wolfSSL_CryptHwMutexUnLock();

        return 0;
    }
    #elif defined(WOLFSSL_STM32F427_RNG) || defined(WOLFSSL_STM32_RNG_NOLIB) \
        || defined(STM32_NUTTX_RNG)

    #ifdef STM32_NUTTX_RNG
        #include "hardware/stm32_rng.h"
        /* Set CONFIG_STM32U5_RNG in NuttX to enable the RCC */
        #define WC_RNG_CR *((volatile uint32_t*)(STM32_RNG_CR))
        #define WC_RNG_SR *((volatile uint32_t*)(STM32_RNG_SR))
        #define WC_RNG_DR *((volatile uint32_t*)(STM32_RNG_DR))
    #else
        /* Comes from "stm32xxxx_hal.h" */
        #define WC_RNG_CR RNG->CR
        #define WC_RNG_SR RNG->SR
        #define WC_RNG_DR RNG->DR
    #endif


    /* Generate a RNG seed using the hardware RNG on the STM32F427
     * directly, following steps outlined in STM32F4 Reference
     * Manual (Chapter 24) for STM32F4xx family. */
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        int ret;
        word32 i;
        (void)os;

        ret = wolfSSL_CryptHwMutexLock();
        if (ret != 0) {
            return ret;
        }

    #ifndef STM32_NUTTX_RNG
        /* enable RNG peripheral clock */
        RCC->AHB2ENR |= RCC_AHB2ENR_RNGEN;
    #endif

        /* enable RNG interrupt, set IE bit in RNG->CR register */
        WC_RNG_CR |= RNG_CR_IE;

        /* enable RNG, set RNGEN bit in RNG->CR. Activates RNG,
         * RNG_LFSR, and error detector */
        WC_RNG_CR |= RNG_CR_RNGEN;

        /* verify no errors, make sure SEIS and CEIS bits are 0
         * in RNG->SR register */
        if (WC_RNG_SR & (RNG_SR_SECS | RNG_SR_CECS)) {
            wolfSSL_CryptHwMutexUnLock();
            return RNG_FAILURE_E;
        }

        for (i = 0; i < sz; i++) {
            /* wait until RNG number is ready */
            while ((WC_RNG_SR & RNG_SR_DRDY) == 0) { }

            /* get value */
            output[i] = WC_RNG_DR;
        }

        wolfSSL_CryptHwMutexUnLock();

        return 0;
    }

    #else

    /* Generate a RNG seed using the STM32 Standard Peripheral Library */
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        int ret;
        word32 i;
        (void)os;

        ret = wolfSSL_CryptHwMutexLock();
        if (ret != 0) {
            return ret;
        }

        /* enable RNG clock source */
        RCC_AHB2PeriphClockCmd(RCC_AHB2Periph_RNG, ENABLE);

        /* reset RNG */
        RNG_DeInit();

        /* enable RNG peripheral */
        RNG_Cmd(ENABLE);

        /* verify no errors with RNG_CLK or Seed */
        if (RNG_GetFlagStatus(RNG_FLAG_SECS | RNG_FLAG_CECS) != RESET) {
            wolfSSL_CryptHwMutexUnLock();
            return RNG_FAILURE_E;
        }

        for (i = 0; i < sz; i++) {
            /* wait until RNG number is ready */
            while (RNG_GetFlagStatus(RNG_FLAG_DRDY) == RESET) { }

            /* get value */
            output[i] = RNG_GetRandomNumber();
        }

        wolfSSL_CryptHwMutexUnLock();

        return 0;
    }
    #endif /* WOLFSSL_STM32_CUBEMX */

#elif defined(WOLFSSL_TIRTOS)
    #warning "potential for not enough entropy, currently being used for testing"
    #include <xdc/runtime/Timestamp.h>
    #include <stdlib.h>
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        int i;
        srand(xdc_runtime_Timestamp_get32());

        for (i = 0; i < sz; i++ ) {
            output[i] = rand() % 256;
            if ((i % 8) == 7) {
                srand(xdc_runtime_Timestamp_get32());
            }
        }

        return 0;
    }

#elif defined(WOLFSSL_PB)

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        word32 i;
        for (i = 0; i < sz; i++)
            output[i] = UTL_Rand();

        (void)os;

        return 0;
    }

#elif defined(WOLFSSL_NUCLEUS)
#include "nucleus.h"
#include "kernel/plus_common.h"

#warning "potential for not enough entropy, currently being used for testing"
int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
{
    int i;
    srand(NU_Get_Time_Stamp());

    for (i = 0; i < sz; i++ ) {
        output[i] = rand() % 256;
        if ((i % 8) == 7) {
            srand(NU_Get_Time_Stamp());
        }
    }

    return 0;
}
#elif defined(WOLFSSL_DEOS) && !defined(CUSTOM_RAND_GENERATE)
    #include "stdlib.h"

    #warning "potential for not enough entropy, currently being used for testing Deos"
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        int i;
        int seed = XTIME(0);
        (void)os;

        for (i = 0; i < sz; i++ ) {
            output[i] = rand_r(&seed) % 256;
            if ((i % 8) == 7) {
                seed = XTIME(0);
                rand_r(&seed);
            }
        }

        return 0;
    }
#elif defined(WOLFSSL_VXWORKS)
    #ifdef WOLFSSL_VXWORKS_6_x
        #include "stdlib.h"
        #warning "potential for not enough entropy, currently being used for testing"
        int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
        {
            int i;
            unsigned int seed = (unsigned int)XTIME(0);
            (void)os;

            for (i = 0; i < sz; i++ ) {
                output[i] = rand_r(&seed) % 256;
                if ((i % 8) == 7) {
                    seed = (unsigned int)XTIME(0);
                    rand_r(&seed);
                }
            }

            return 0;
        }
    #else
        #include <randomNumGen.h>
        #include <tickLib.h>

        int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz) {
            STATUS                status   = ERROR;
            RANDOM_NUM_GEN_STATUS r_status = RANDOM_NUM_GEN_ERROR;
            _Vx_ticks_t           seed = 0;

            #ifdef VXWORKS_SIM
                /* cannot generate true entropy with VxWorks simulator */
                #warning "not enough entropy, simulator for testing only"
                int i = 0;

                for (i = 0; i < 1000; i++) {
                    randomAddTimeStamp();
                }
            #endif

            /*
              wolfSSL can request 52 Bytes of random bytes. We need to add
              buffer to the entropy pool to ensure we can get more than 32 Bytes.
              Because VxWorks has entropy limits (ENTROPY_MIN and ENTROPY_MAX)
              defined as 256 and 1024 bits, see randomSWNumGenLib.c.

              randStatus() can return the following status:
              RANDOM_NUM_GEN_NO_ENTROPY when entropy is 0
              RANDOM_NUM_GEN_ERROR, entropy is not initialized
              RANDOM_NUM_GEN_NOT_ENOUGH_ENTROPY if entropy < 32 Bytes
              RANDOM_NUM_GEN_ENOUGH_ENTROPY if entropy is between 32 and 128 Bytes
              RANDOM_NUM_GEN_MAX_ENTROPY if entropy is greater than 128 Bytes
            */

            do {
                seed = tickGet();
                status = randAdd(&seed, sizeof(_Vx_ticks_t), 2);
                if (status == OK)
                    r_status = randStatus();

            } while (r_status != RANDOM_NUM_GEN_MAX_ENTROPY &&
                     r_status != RANDOM_NUM_GEN_ERROR && status == OK);

            if (r_status == RANDOM_NUM_GEN_ERROR)
                return RNG_FAILURE_E;

            status = randBytes (output, sz);

            if (status == ERROR) {
                return RNG_FAILURE_E;
            }

            return 0;
        }
    #endif
#elif defined(WOLFSSL_NRF51) || defined(WOLFSSL_NRF5x)
    #include "app_error.h"
    #include "nrf_drv_rng.h"
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        int remaining = sz, pos = 0;
        word32 err_code;
        byte available;
        static byte initialized = 0;

        (void)os;

        /* Make sure RNG is running */
        if (!initialized) {
            err_code = nrf_drv_rng_init(NULL);
            if (err_code != NRF_SUCCESS && err_code != NRF_ERROR_INVALID_STATE
            #ifdef NRF_ERROR_MODULE_ALREADY_INITIALIZED
                && err_code != NRF_ERROR_MODULE_ALREADY_INITIALIZED
            #endif
            ) {
                return -1;
            }
            initialized = 1;
        }

        while (remaining > 0) {
            int length;
            available = 0;
            nrf_drv_rng_bytes_available(&available); /* void func */
            length = (remaining < available) ? remaining : available;
            if (length > 0) {
                err_code = nrf_drv_rng_rand(&output[pos], length);
                if (err_code != NRF_SUCCESS) {
                    break;
                }
                remaining -= length;
                pos += length;
            }
        }

        return (err_code == NRF_SUCCESS) ? 0 : -1;
    }

#elif defined(HAVE_WNR)

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        if (os == NULL || output == NULL || wnr_ctx == NULL ||
                wnr_timeout < 0) {
            return BAD_FUNC_ARG;
        }

        if (wnr_mutex_init == 0) {
            WOLFSSL_MSG("netRandom context must be created before use");
            return RNG_FAILURE_E;
        }

        if (wc_LockMutex(&wnr_mutex) != 0) {
            WOLFSSL_MSG("Bad Lock Mutex wnr_mutex");
            return BAD_MUTEX_E;
        }

        if (wnr_get_entropy(wnr_ctx, wnr_timeout, output, sz, sz) !=
                WNR_ERROR_NONE)
            return RNG_FAILURE_E;

        wc_UnLockMutex(&wnr_mutex);

        return 0;
    }

#elif defined(INTIME_RTOS)
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        uint32_t randval;
        word32 len;

        if (output == NULL) {
            return BUFFER_E;
        }

    #ifdef INTIMEVER
        /* If INTIMEVER exists then it is INTIME RTOS v6 or later */
        #define INTIME_RAND_FUNC arc4random
        len = 4;
    #else
        /* v5 and older */
        #define INTIME_RAND_FUNC rand
        srand(time(0));
        len = 2; /* don't use all 31 returned bits */
    #endif

        while (sz > 0) {
            if (sz < len)
                len = sz;
            randval = INTIME_RAND_FUNC();
            XMEMCPY(output, &randval, len);
            output += len;
            sz -= len;
        }
        (void)os;

        return 0;
    }

#elif defined(WOLFSSL_WICED)
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        int ret;
        (void)os;

        if (output == NULL || UINT16_MAX < sz) {
            return BUFFER_E;
        }

        if ((ret = wiced_crypto_get_random((void*) output, sz) )
                         != WICED_SUCCESS) {
            return ret;
        }

        return ret;
    }

#elif defined(WOLFSSL_NETBURNER)
    #warning using NetBurner pseudo random GetRandomByte for seed
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        word32 i;
        (void)os;

        if (output == NULL) {
            return BUFFER_E;
        }

        for (i = 0; i < sz; i++) {
            output[i] = GetRandomByte();

            /* check if was a valid random number */
            if (!RandomValid())
                return RNG_FAILURE_E;
        }

        return 0;
    }
#elif defined(IDIRECT_DEV_RANDOM)

    extern int getRandom( int sz, unsigned char *output );

    int GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        int num_bytes_returned = 0;

        num_bytes_returned = getRandom( (int) sz, (unsigned char *) output );

        return 0;
    }

#elif defined(WOLFSSL_CAAM)

    #include <wolfssl/wolfcrypt/port/caam/wolfcaam.h>

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        unsigned int args[4] = {0};
        CAAM_BUFFER buf[1];
        int ret    = 0;
        int times  = 1000, i; /* 1000 is an arbitrary number chosen */
        word32 idx = 0;

        (void)os;

        if (output == NULL) {
            return BUFFER_E;
        }

        /* Check Waiting to make sure entropy is ready */
        for (i = 0; i < times; i++) {
            buf[0].BufferType = DataBuffer | LastBuffer;
            buf[0].TheAddress = (CAAM_ADDRESS)(output + idx);
            buf[0].Length     = ((sz - idx) < WC_CAAM_MAX_ENTROPY)?
                                sz - idx : WC_CAAM_MAX_ENTROPY;

            args[0] = buf[0].Length;
            ret = wc_caamAddAndWait(buf, 1, args, CAAM_ENTROPY);
            if (ret == 0) {
                idx += buf[0].Length;
                if (idx == sz)
                    break;
            }

            /* driver could be waiting for entropy */
            if (ret != WC_NO_ERR_TRACE(RAN_BLOCK_E) && ret != 0) {
                return ret;
            }
#ifndef WOLFSSL_IMXRT1170_CAAM
            usleep(100);
#endif
        }

        if (i == times && ret != 0) {
             return RNG_FAILURE_E;
        }
        else { /* Success case */
            ret = 0;
        }

        return ret;
    }

#elif defined(WOLFSSL_APACHE_MYNEWT)

    #include <stdlib.h>
    #include "os/os_time.h"
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        int i;
        srand(os_time_get());

        for (i = 0; i < sz; i++ ) {
            output[i] = rand() % 256;
            if ((i % 8) == 7) {
                srand(os_time_get());
            }
        }

        return 0;
    }

#elif defined(ARDUINO)

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        int ret = 0;
        word32 rand;
        while (sz > 0) {
            word32 len = sizeof(rand);
            if (sz < len)
                len = sz;
        /* Get an Arduino framework random number */
        #if defined(ARDUINO_SAMD_NANO_33_IOT) || \
            defined(ARDUINO_ARCH_RP2040)
            /* Known, tested boards working with random() */
            rand = random();
        #elif defined(ARDUINO_SAM_DUE)
            /* See: https://github.com/avrxml/asf/tree/master/sam/utils/cmsis/sam3x/include */
            #if defined(__SAM3A4C__)
                #ifndef TRNG
                    #define TRNG (0x400BC000U)
                #endif
            #elif defined(__SAM3A8C__)
                #ifndef TRNG
                    #define TRNG (0x400BC000U)
                #endif
            #elif defined(__SAM3X4C__)
                #ifndef TRNG
                    #define TRNG (0x400BC000U)
                #endif
            #elif defined(__SAM3X4E__)
                #ifndef TRNG
                    #define TRNG (0x400BC000U)
                #endif
            #elif defined(__SAM3X8C__)
                #ifndef TRNG
                    #define TRNG (0x400BC000U)
                #endif
            #elif defined(__SAM3X8E__)
                /* This is the Arduino Due */
                #ifndef TRNG
                    #define TRNG (0x400BC000U)
                #endif
            #elif  defined(__SAM3A8H__)
                #ifndef TRNG
                    #define TRNG (0x400BC000U)
                #endif
            #else
                #ifndef TRNG
                    #error "Unknown TRNG for this device"
                #endif
            #endif

            srand(analogRead(0));
            rand = trng_read_output_data(TRNG);
        #elif defined(__STM32__)
            /* TODO: confirm this is proper random number on Arduino STM32 */
            #warning "Not yet tested on STM32 targets"
            rand = random();
        #else
            /* TODO: Pull requests appreciated for new targets.
             * Do *all* other Arduino boards support random()?
             * Probably not 100%, but most will likely work: */
            rand = random();
        #endif

            XMEMCPY(output, &rand, len);
            output += len;
            sz -= len;
        }

        return ret;
    }

#elif defined(WOLFSSL_ESPIDF)

    /* Espressif */
    #if defined(WOLFSSL_ESP32) || defined(WOLFSSL_ESPWROOM32SE)

        /* Espressif ESP32 */
        #include <esp_system.h>
        #if defined(CONFIG_IDF_TARGET_ESP32S2) || \
            defined(CONFIG_IDF_TARGET_ESP32S3)
            #include <esp_random.h>
        #endif

        int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
        {
            word32 rand;
            while (sz > 0) {
                word32 len = sizeof(rand);
                if (sz < len)
                    len = sz;
                /* Get one random 32-bit word from hw RNG */
                rand = esp_random( );
                XMEMCPY(output, &rand, len);
                output += len;
                sz -= len;
            }

            return 0;
        }

    #elif defined(WOLFSSL_ESP8266)

        /* Espressif ESP8266 */
        #include <esp_system.h>

        int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
        {
    #if defined(DEBUG_WOLFSSL)
            WOLFSSL_ENTER("ESP8266 Random");
    #endif
            word32 rand;
            while (sz > 0) {
                word32 len = sizeof(rand);
                if (sz < len)
                    len = sz;
                /* Get one random 32-bit word from hw RNG */
                rand = esp_random( );
                XMEMCPY(output, &rand, len);
                output += len;
                sz -= len;
            }

            return 0;
        }
    #endif /* end WOLFSSL_ESPIDF */

#elif defined(WOLFSSL_LINUXKM)

    #ifndef LINUXKM_LKCAPI_REGISTER_HASH_DRBG_DEFAULT
        #include <linux/random.h>
    #endif

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        (void)os;
        int ret;

    #ifdef HAVE_ENTROPY_MEMUSE
        ret = wc_Entropy_Get(MAX_ENTROPY_BITS, output, sz);
        if (ret == 0)
            return 0;
        #ifdef ENTROPY_MEMUSE_FORCE_FAILURE
        return ret;
        #endif
    #endif

    #if defined(HAVE_INTEL_RDSEED) || defined(HAVE_AMD_RDSEED)
        if (IS_INTEL_RDSEED(intel_flags)) {
            ret = wc_GenerateSeed_IntelRD(NULL, output, sz);
            if (ret == 0)
                return 0;
            #ifdef FORCE_FAILURE_RDSEED
            return ret;
            #endif
        }
    #endif /* HAVE_INTEL_RDSEED || HAVE_AMD_RDSEED */

    #ifdef LINUXKM_LKCAPI_REGISTER_HASH_DRBG_DEFAULT
        #if !defined(HAVE_ENTROPY_MEMUSE) && \
            !defined(HAVE_INTEL_RDSEED) && \
            !defined(HAVE_AMD_RDSEED)
            #error LINUXKM_LKCAPI_REGISTER_HASH_DRBG_DEFAULT requires an intrinsic entropy source.
        #else
            return ret;
        #endif
    #else
        (void)ret;

        get_random_bytes(output, sz);
        return 0;
    #endif
    }

#elif defined(WOLFSSL_BSDKM)
    #include <sys/random.h>
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        (void)os;
        int ret;

    #ifdef HAVE_ENTROPY_MEMUSE
        ret = wc_Entropy_Get(MAX_ENTROPY_BITS, output, sz);
        if (ret == 0) {
            return 0;
        }
        #ifdef ENTROPY_MEMUSE_FORCE_FAILURE
        /* Don't fallback to /dev/urandom. */
        return ret;
        #endif
    #endif

    #if defined(HAVE_INTEL_RDSEED) || defined(HAVE_AMD_RDSEED)
        if (IS_INTEL_RDSEED(intel_flags)) {
            ret = wc_GenerateSeed_IntelRD(NULL, output, sz);
        #ifndef FORCE_FAILURE_RDSEED
            if (ret == 0)
        #endif
            {
                return ret;
            }
        }
    #endif /* HAVE_INTEL_RDSEED || HAVE_AMD_RDSEED */

        (void)ret;

        arc4random_buf(output, sz);
        return 0;
    }
#elif defined(WOLFSSL_RENESAS_TSIP)

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        (void)os;
        return wc_tsip_GenerateRandBlock(output, sz);
    }


#elif defined(WOLFSSL_SCE) && !defined(WOLFSSL_SCE_NO_TRNG)
    #include "hal_data.h"

    #ifndef WOLFSSL_SCE_TRNG_HANDLE
        #define WOLFSSL_SCE_TRNG_HANDLE g_sce_trng
    #endif

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        word32 ret;
        word32 blocks;
        word32 len = sz;

        ret = WOLFSSL_SCE_TRNG_HANDLE.p_api->open(WOLFSSL_SCE_TRNG_HANDLE.p_ctrl,
                                                  WOLFSSL_SCE_TRNG_HANDLE.p_cfg);
        if (ret != SSP_SUCCESS && ret != SSP_ERR_CRYPTO_ALREADY_OPEN) {
            /* error opening TRNG driver */
            return -1;
        }

        blocks = sz / sizeof(word32);
        if (blocks > 0) {
            ret = WOLFSSL_SCE_TRNG_HANDLE.p_api->read(WOLFSSL_SCE_TRNG_HANDLE.p_ctrl,
                                                       (word32*)output, blocks);
            if (ret != SSP_SUCCESS) {
                return -1;
            }
        }

        len = len - (blocks * sizeof(word32));
        if (len > 0) {
            word32 tmp;

            if (len > sizeof(word32)) {
                return -1;
            }
            ret = WOLFSSL_SCE_TRNG_HANDLE.p_api->read(WOLFSSL_SCE_TRNG_HANDLE.p_ctrl,
                                                      (word32*)&tmp, 1);
            if (ret != SSP_SUCCESS) {
                return -1;
            }
            XMEMCPY(output + (blocks * sizeof(word32)), (byte*)&tmp, len);
        }

        ret = WOLFSSL_SCE_TRNG_HANDLE.p_api->close(WOLFSSL_SCE_TRNG_HANDLE.p_ctrl);
        if (ret != SSP_SUCCESS) {
            /* error opening TRNG driver */
            return -1;
        }
        return 0;
    }
#elif defined(CUSTOM_RAND_GENERATE_BLOCK)
    /* #define CUSTOM_RAND_GENERATE_BLOCK myRngFunc
     * extern int myRngFunc(byte* output, word32 sz);
     */

#elif defined(__MICROBLAZE__)
    #warning weak source of entropy
    #define LPD_SCNTR_BASE_ADDRESS 0xFF250000

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        word32* cnt;
        word32 i;

        /* using current time with srand */
        cnt = (word32*)LPD_SCNTR_BASE_ADDRESS;
        srand(*cnt | *(cnt+1));

        for (i = 0; i < sz; i++)
            output[i] = rand();

        (void)os;
        return 0;
    }

#elif defined(WOLFSSL_ZEPHYR)

    #ifdef __has_include
        #if __has_include(<zephyr/version.h>)
            #include <zephyr/version.h>
        #else
            #include <version.h>
        #endif
    #else
        #include <version.h>
    #endif

    #include <sys/types.h>

    #if KERNEL_VERSION_NUMBER >= 0x30500
        #include <zephyr/random/random.h>
    #else
        #if KERNEL_VERSION_NUMBER >= 0x30100
            #include <zephyr/random/rand32.h>
        #else
            #include <random/rand32.h>
        #endif
    #endif

    #if KERNEL_VERSION_NUMBER >= 0x40300
        #include <time.h>
    #elif KERNEL_VERSION_NUMBER >= 0x30100
        #include <zephyr/posix/time.h>
    #else
        #include <posix/time.h>
    #endif

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        sys_rand_get(output, sz);
        return 0;
    }

#elif defined(WOLFSSL_TELIT_M2MB)

        #include "stdlib.h"
        static long get_timestamp(void) {
            long myTime = 0;
            INT32 fd = m2mb_rtc_open("/dev/rtc0", 0);
            if (fd >= 0) {
                M2MB_RTC_TIMEVAL_T timeval;
                m2mb_rtc_ioctl(fd, M2MB_RTC_IOCTL_GET_TIMEVAL, &timeval);
                myTime = timeval.msec;
                m2mb_rtc_close(fd);
            }
            return myTime;
        }
        int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
        {
            int i;
            srand(get_timestamp());
            for (i = 0; i < sz; i++ ) {
                output[i] = rand() % 256;
                if ((i % 8) == 7) {
                    srand(get_timestamp());
                }
            }
            return 0;
        }
#elif defined(WOLFSSL_SE050) && !defined(WOLFSSL_SE050_NO_TRNG)
     #include <wolfssl/wolfcrypt/port/nxp/se050_port.h>

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz){
        int ret = 0;

        (void)os;

        if (output == NULL) {
            return BUFFER_E;
        }
        ret = wolfSSL_CryptHwMutexLock();
        if (ret == 0) {
            ret = se050_get_random_number(sz, output);
            wolfSSL_CryptHwMutexUnLock();
        }
        return ret;
    }

#elif defined(WOLFSSL_NXP_RNG_1)
    #include "fsl_rng.h"

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz) {
        (void)os;

        if (output == NULL) {
            return BUFFER_E;
        }

        if (RNG_GetRandomData(RNG, output, sz) != kStatus_Success)
            return RNG_FAILURE_E;

        return 0;
    }

#elif defined(WOLFSSL_VA416X0_TRNG)
    /* Vorago VA416x0 hardware TRNG (an Arm CryptoCell-style entropy block).
     * Used to seed the SP800-90A Hash-DRBG (keep HAVE_HASHDRBG enabled); the
     * TRNG yields only ~1.25 kb/s of entropy, so the DRBG expands it.
     *
     * Build: define WOLFSSL_VA416X0_TRNG, and have the VA416xx SDK header
     * "va416xx.h" on the include path (provides VOR_SYSCONFIG / VOR_TRNG and
     * the register field macros). There is no SDK HAL driver for the TRNG, so
     * it is accessed at the register level below. The tuning macros
     * WOLFSSL_VA416X0_TRNG_SAMPLE_CNT, WOLFSSL_VA416X0_TRNG_MAX_RETRY and
     * WOLFSSL_VA416X0_TRNG_TIMEOUT have overridable defaults defined below.
     *
     * Note: the TRNG PERIPHERAL_RESET bit is active low and must be released
     * or every TRNG register write is silently ignored. */
    #include "va416xx.h"

    /* Ring-oscillator sample count (must be non-zero). May need tuning on
     * hardware: too low results in repeated autocorrelation/CRNGT errors. */
    #ifndef WOLFSSL_VA416X0_TRNG_SAMPLE_CNT
        #define WOLFSSL_VA416X0_TRNG_SAMPLE_CNT 1000
    #endif
    #ifndef WOLFSSL_VA416X0_TRNG_MAX_RETRY
        #define WOLFSSL_VA416X0_TRNG_MAX_RETRY 10
    #endif
    /* Max poll iterations waiting for one 192-bit entropy block before
     * giving up (guards against a non-responsive TRNG). */
    #ifndef WOLFSSL_VA416X0_TRNG_TIMEOUT
        #define WOLFSSL_VA416X0_TRNG_TIMEOUT 1000000
    #endif
    #if WOLFSSL_VA416X0_TRNG_SAMPLE_CNT == 0
        #error "WOLFSSL_VA416X0_TRNG_SAMPLE_CNT must be non-zero"
    #endif
    #if WOLFSSL_VA416X0_TRNG_TIMEOUT == 0
        #error "WOLFSSL_VA416X0_TRNG_TIMEOUT must be non-zero"
    #endif

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        word32 i;
        word32 reg;
        word32 chunk;
        word32 timeout;
        word32 ehr[6]; /* 192-bit entropy holding register */
        int retry;
        int ret;

        (void)os;

        if (output == NULL) {
            return BUFFER_E;
        }

        /* serialize access to the shared TRNG hardware */
        ret = wolfSSL_CryptHwMutexLock();
        if (ret != 0) {
            return ret;
        }

        /* enable the TRNG peripheral clock and release it from reset (the
         * reset bit is active low: 0 = held in reset, 1 = released) */
        VOR_SYSCONFIG->PERIPHERAL_CLK_ENABLE |=
            SYSCONFIG_PERIPHERAL_CLK_ENABLE_TRNG_Msk;
        VOR_SYSCONFIG->PERIPHERAL_RESET |=
            SYSCONFIG_PERIPHERAL_RESET_TRNG_Msk;

        /* mask all interrupts (poll instead) and clear any stale status */
        VOR_TRNG->IMR = TRNG_IMR_EHR_VALID_INT_MASK_Msk |
                        TRNG_IMR_AUTOCORR_ERR_INT_MASK_Msk |
                        TRNG_IMR_CRNGT_ERR_INT_MASK_Msk |
                        TRNG_IMR_VN_ERR_INT_MASK_Msk;
        VOR_TRNG->ICR = TRNG_ICR_EHR_VALID_Msk | TRNG_ICR_AUTOCORR_ERR_Msk |
                        TRNG_ICR_CRNGT_ERR_Msk | TRNG_ICR_VN_ERR_Msk;

        /* CONFIG = 0 sets RND_SRC_SEL = 0, which selects the ring-oscillator
         * entropy source (per the VA416x0 reference manual) and clears the
         * rest of the register; set the sample rate and keep the health tests
         * enabled (no DEBUG_CONTROL bypass) */
        VOR_TRNG->CONFIG = 0;
        VOR_TRNG->SAMPLE_CNT1 = WOLFSSL_VA416X0_TRNG_SAMPLE_CNT;
        VOR_TRNG->DEBUG_CONTROL = 0;

        for (i = 0; i < sz; ) {
            retry = 0;
            timeout = WOLFSSL_VA416X0_TRNG_TIMEOUT;

            /* start entropy collection */
            VOR_TRNG->RND_SOURCE_ENABLE =
                TRNG_RND_SOURCE_ENABLE_RND_SRC_EN_Msk;

            for (;;) {
                reg = VOR_TRNG->ISR;
                if ((reg & (TRNG_ISR_AUTOCORR_ERR_Msk |
                            TRNG_ISR_CRNGT_ERR_Msk |
                            TRNG_ISR_VN_ERR_Msk)) != 0) {
                    /* health-test failure: stop, then clear the error flags
                     * and any latched EHR_VALID so a stale/invalid block is
                     * not consumed on the next iteration, then re-collect */
                    VOR_TRNG->RND_SOURCE_ENABLE = 0;
                    VOR_TRNG->ICR = TRNG_ICR_EHR_VALID_Msk |
                                    TRNG_ICR_AUTOCORR_ERR_Msk |
                                    TRNG_ICR_CRNGT_ERR_Msk |
                                    TRNG_ICR_VN_ERR_Msk;
                    if (++retry > WOLFSSL_VA416X0_TRNG_MAX_RETRY) {
                        ForceZero(ehr, sizeof(ehr));
                        wolfSSL_CryptHwMutexUnLock();
                        return RNG_FAILURE_E;
                    }
                    timeout = WOLFSSL_VA416X0_TRNG_TIMEOUT;
                    VOR_TRNG->RND_SOURCE_ENABLE =
                        TRNG_RND_SOURCE_ENABLE_RND_SRC_EN_Msk;
                    continue;
                }
                if ((VOR_TRNG->VALID & TRNG_VALID_EHR_VALID_Msk) != 0) {
                    break;
                }
                if (--timeout == 0) {
                    VOR_TRNG->RND_SOURCE_ENABLE = 0;
                    ForceZero(ehr, sizeof(ehr));
                    wolfSSL_CryptHwMutexUnLock();
                    return RNG_FAILURE_E;
                }
            }

            /* read 192 bits of entropy (6 x 32-bit words) */
            ehr[0] = VOR_TRNG->EHR_DATA0;
            ehr[1] = VOR_TRNG->EHR_DATA1;
            ehr[2] = VOR_TRNG->EHR_DATA2;
            ehr[3] = VOR_TRNG->EHR_DATA3;
            ehr[4] = VOR_TRNG->EHR_DATA4;
            ehr[5] = VOR_TRNG->EHR_DATA5;

            /* reading the EHR clears EHR_VALID; stop the source and ack */
            VOR_TRNG->RND_SOURCE_ENABLE = 0;
            VOR_TRNG->ICR = TRNG_ICR_EHR_VALID_Msk;

            chunk = sz - i;
            if (chunk > sizeof(ehr)) {
                chunk = sizeof(ehr);
            }
            XMEMCPY(&output[i], (byte*)ehr, chunk);
            i += chunk;
        }

        ForceZero(ehr, sizeof(ehr)); /* scrub seed material from stack */
        wolfSSL_CryptHwMutexUnLock();
        return 0;
    }

#elif defined(DOLPHIN_EMULATOR) || defined (WOLFSSL_NDS)

        int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
        {
            word32 i;
            (void)os;
            srand(time(NULL));
            for (i = 0; i < sz; i++)
                output[i] = (byte)rand();
            return 0;
        }
#elif defined(WOLFSSL_MAXQ108X) || defined(WOLFSSL_MAXQ1065)

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        (void)os;

        return maxq10xx_random(output, sz);
    }
#elif defined(MAX3266X_RNG)
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        #ifdef WOLFSSL_MAX3266X
        int status;
        #endif /* WOLFSSL_MAX3266X */
        static int initDone = 0;
        (void)os;
        if (initDone == 0) {
            #ifdef WOLFSSL_MAX3266X
            status = wolfSSL_HwRngMutexLock();
            if (status != 0) {
                return status;
            }
            #endif /* WOLFSSL_MAX3266X */
            if(MXC_TRNG_HealthTest() != 0) {
                #ifdef DEBUG_WOLFSSL
                WOLFSSL_MSG("TRNG HW Health Test Failed");
                #endif /* DEBUG_WOLFSSL */
                #ifdef WOLFSSL_MAX3266X
                wolfSSL_HwRngMutexUnLock();
                #endif /* WOLFSSL_MAX3266X */
                return WC_HW_E;
            }
            #ifdef WOLFSSL_MAX3266X
            wolfSSL_HwRngMutexUnLock();
            #endif /* WOLFSSL_MAX3266X */
            initDone = 1;
        }
        return wc_MXC_TRNG_Random(output, sz);
    }

#elif defined(CY_USING_HAL) && defined(COMPONENT_WOLFSSL)

    /* Infineon/Cypress HAL RNG implementation */
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        cyhal_trng_t obj;
        cy_rslt_t result;
        uint32_t val;
        word32 i = 0;

        (void)os;

        result = cyhal_trng_init(&obj);
        if (result == CY_RSLT_SUCCESS) {
            while (i < sz) {
                /* If not aligned or there is odd/remainder add single byte */
                if( (i + sizeof(word32)) > sz ||
                    ((wc_ptr_t)&output[i] % sizeof(word32)) != 0
                ) {
                    val = cyhal_trng_generate(&obj);
                    output[i++] = (byte)val;
                }
                else {
                    /* Use native 32 instruction */
                    val = cyhal_trng_generate(&obj);
                    *((uint32_t*)&output[i]) = val;
                    i += sizeof(word32);
                }
            }
            cyhal_trng_free(&obj);
        }
        return 0;
    }

#elif defined(WOLFSSL_SAFERTOS) || defined(WOLFSSL_LEANPSK) || \
      defined(WOLFSSL_IAR_ARM)  || defined(WOLFSSL_MDK_ARM) || \
      defined(WOLFSSL_uITRON4)  || defined(WOLFSSL_uTKERNEL2) || \
      defined(WOLFSSL_LPC43xx)  || defined(NO_STM32_RNG) || \
      defined(MBED)             || defined(WOLFSSL_EMBOS) || \
      defined(WOLFSSL_GENSEED_FORTEST) || defined(WOLFSSL_CHIBIOS) || \
      defined(WOLFSSL_CONTIKI)  || defined(WOLFSSL_AZSPHERE)

    /* these platforms do not have a default random seed and
       you'll need to implement your own wc_GenerateSeed or define via
       CUSTOM_RAND_GENERATE_BLOCK */

    #define USE_TEST_GENSEED

#elif defined(NO_DEV_RANDOM)

    /* Allow bare-metal targets to use cryptoCb as seed provider */
    #if defined(WOLF_CRYPTO_CB)

    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        int ret = WC_NO_ERR_TRACE(WC_HW_E);

        #ifndef WOLF_CRYPTO_CB_FIND
        if (os->devId != INVALID_DEVID)
        #endif
        {
            ret = wc_CryptoCb_RandomSeed(os, output, sz);
            if (ret == WC_NO_ERR_TRACE(CRYPTOCB_UNAVAILABLE)) {
                ret = WC_HW_E;
            }
        }

        return ret;
    }

    #else /* defined(WOLF_CRYPTO_CB)*/

    #error "you need to write an os specific wc_GenerateSeed() here"

    /*
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        return 0;
    }
    */

   #endif  /* !defined(WOLF_CRYPTO_CB) */

#else

    /* may block */
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        int ret = 0;

        if (os == NULL) {
            return BAD_FUNC_ARG;
        }

    #ifdef WOLF_CRYPTO_CB
        #ifndef WOLF_CRYPTO_CB_FIND
        if (os->devId != INVALID_DEVID)
        #endif
        {
            ret = wc_CryptoCb_RandomSeed(os, output, sz);
            if (ret != WC_NO_ERR_TRACE(CRYPTOCB_UNAVAILABLE))
                return ret;
            /* fall-through when unavailable */
            ret = 0; /* reset error code */
        }
    #endif

    #ifdef HAVE_ENTROPY_MEMUSE
        ret = wc_Entropy_Get(MAX_ENTROPY_BITS, output, sz);
        if (ret == 0) {
            /* success, we're done */
            return ret;
        }
    #ifdef ENTROPY_MEMUSE_FORCE_FAILURE
        /* Don't fall back to /dev/urandom. */
        return ret;
    #else
        /* Reset error and fall back to using /dev/urandom. */
        ret = 0;
    #endif
    #endif

    #if !defined(HAVE_ENTROPY_MEMUSE) || !defined(ENTROPY_MEMUSE_FORCE_FAILURE)

    #if defined(HAVE_INTEL_RDSEED) || defined(HAVE_AMD_RDSEED)
        if (IS_INTEL_RDSEED(intel_flags)) {
             ret = wc_GenerateSeed_IntelRD(NULL, output, sz);
             if (ret == 0) {
                 /* success, we're done */
                 return ret;
             }
        #ifdef FORCE_FAILURE_RDSEED
             /* Don't fall back to /dev/urandom. */
             return ret;
        #else
             /* Reset error and fall back to using /dev/urandom. */
             ret = 0;
        #endif
        }
    #ifdef FORCE_FAILURE_RDSEED
        else {
            /* Don't fall back to /dev/urandom */
            return MISSING_RNG_E;
        }
    #endif
    #endif /* HAVE_INTEL_RDSEED || HAVE_AMD_RDSEED */

    #if (!defined(HAVE_INTEL_RDSEED) && !defined(HAVE_AMD_RDSEED)) || \
        !defined(FORCE_FAILURE_RDSEED)

    #if defined(WOLFSSL_GETRANDOM) || defined(HAVE_GETRANDOM)
        {
            word32 grSz = sz;
            byte* grOutput = output;

            while (grSz) {
                ssize_t len;

                errno = 0;
                len = getrandom(grOutput, grSz, 0);
                if (len == -1) {
                    if (errno == EINTR) {
                        /* interrupted, call getrandom again */
                        continue;
                    }
                    else {
                        ret = READ_RAN_E;
                    }
                    break;
                }

                grSz     -= (word32)len;
                grOutput += len;
            }
            if (ret == 0)
                return ret;
        #ifdef FORCE_FAILURE_GETRANDOM
            /* don't fall back to /dev/urandom */
            return ret;
        #elif !defined(NO_FILESYSTEM)
            /* reset error and fall back to using /dev/urandom if filesystem
             * support is compiled in */
            ret = 0;
        #endif
        }
    #endif

#ifndef NO_FILESYSTEM
    #ifdef WOLFSSL_KEEP_RNG_SEED_FD_OPEN
        if (!os->seedFdOpen)
        {
        #ifndef NO_DEV_URANDOM /* way to disable use of /dev/urandom */
            os->fd = wc_open_cloexec("/dev/urandom", O_RDONLY);
            #if defined(DEBUG_WOLFSSL)
                WOLFSSL_MSG("opened /dev/urandom.");
            #endif /* DEBUG_WOLFSSL */
            if (os->fd == XBADFD)
        #endif /* NO_DEV_URANDOM */
            {
                /* may still have /dev/random */
                os->fd = wc_open_cloexec("/dev/random", O_RDONLY);
            #if defined(DEBUG_WOLFSSL)
                WOLFSSL_MSG("opened /dev/random.");
            #endif /* DEBUG_WOLFSSL */
                if (os->fd == XBADFD)
                    return OPEN_RAN_E;
                else {
                    os->keepSeedFdOpen = 0;
                    os->seedFdOpen = 1;
                }
            }
            else {
                os->keepSeedFdOpen = 1;
                os->seedFdOpen = 1;
            }
        }
    #else /* WOLFSSL_KEEP_RNG_SEED_FD_OPEN */
        #ifndef NO_DEV_URANDOM /* way to disable use of /dev/urandom */
        os->fd = wc_open_cloexec("/dev/urandom", O_RDONLY);
        #if defined(DEBUG_WOLFSSL)
            WOLFSSL_MSG("opened /dev/urandom.");
        #endif /* DEBUG_WOLFSSL */
        if (os->fd == XBADFD)
        #endif /* !NO_DEV_URANDOM */
        {
            /* may still have /dev/random */
            os->fd = wc_open_cloexec("/dev/random", O_RDONLY);
        #if defined(DEBUG_WOLFSSL)
            WOLFSSL_MSG("opened /dev/random.");
        #endif /* DEBUG_WOLFSSL */
            if (os->fd == XBADFD)
                return OPEN_RAN_E;
        }
    #endif /* WOLFSSL_KEEP_RNG_SEED_FD_OPEN */
    #if defined(DEBUG_WOLFSSL)
        WOLFSSL_MSG("rnd read...");
    #endif /* DEBUG_WOLFSSL */
        while (sz) {
            int len = (int)read(os->fd, output, sz);
            if (len == -1) {
                ret = READ_RAN_E;
                break;
            }

            sz     -= (word32)len;
            output += len;

            if (sz) {
    #if defined(BLOCKING) || defined(WC_RNG_BLOCKING)
                sleep(0);             /* context switch */
    #else
                ret = RAN_BLOCK_E;
                break;
    #endif /* BLOCKING || WC_RNG_BLOCKING */
            }
        }
    #ifdef WOLFSSL_KEEP_RNG_SEED_FD_OPEN
        if (!os->keepSeedFdOpen && os->seedFdOpen)
        {
            close(os->fd);
            os->fd = -1;
            os->seedFdOpen = 0;
        }
    #else
        close(os->fd);
    #endif /* WOLFSSL_KEEP_RNG_SEED_FD_OPEN */
#else /* NO_FILESYSTEM */
        (void)output;
        (void)sz;
        ret = NOT_COMPILED_IN;
#endif /* NO_FILESYSTEM */

        return ret;

    #endif /* (!HAVE_INTEL_RDSEED && !HAVE_AMD_RDSEED) || !FORCE_FAILURE_RDSEED */

    #endif /*!HAVE_ENTROPY_MEMUSE || !ENTROPY_MEMUSE_FORCE_FAILURE */

    }

#endif

#ifdef USE_TEST_GENSEED
    #if !defined(_MSC_VER) && !defined(__TASKING__)
        #warning "write a real random seed!!!!, just for testing now"
    #else
        #pragma message("Warning: write a real random seed!!!!, just for testing now")
    #endif
    int wc_GenerateSeed(OS_Seed* os, byte* output, word32 sz)
    {
        word32 i;
        for (i = 0; i < sz; i++ )
            output[i] = (byte)i;

        (void)os;

        return 0;
    }
#endif
/* End wc_GenerateSeed */

#if defined(CUSTOM_RAND_GENERATE_BLOCK) && defined(WOLFSSL_KCAPI)
#include <fcntl.h>
int wc_hwrng_generate_block(byte *output, word32 sz)
{
    int fd;
    int ret = 0;
    fd = wc_open_cloexec("/dev/hwrng", O_RDONLY);
    if (fd == -1)
        return OPEN_RAN_E;
    while(sz)
    {
        int len = (int)read(fd, output, sz);
        if (len == -1)
        {
            ret = READ_RAN_E;
            break;
        }
        sz -= len;
        output += len;
    }
    close(fd);
    return ret;
}
#endif

#endif /* WC_NO_RNG */