bring_your_own_fips202

Bring Your Own FIPS-202

This directory contains a minimal example for using mldsa-native with a custom FIPS-202 (SHA-3/SHAKE) implementation. We use tiny_sha3¹ as an example.

Use Case

Use this approach when:

• You need only one ML-DSA parameter set (44, 65, or 87)
• Your application already has a FIPS-202 software/hardware implementation you want to reuse

Components

1. Arithmetic part of mldsa-native: mldsa/src/ (excluding fips202/)
2. A secure random number generator implementing randombytes.h
3. Custom FIPS-202 implementation with headers compatible with:
   • fips202.h
   • fips202x4.h
4. Your application source code

Configuration

The configuration file mldsa_native_config.h sets:

• MLD_CONFIG_FIPS202_CUSTOM_HEADER: Path to your custom fips202.h
• MLD_CONFIG_FIPS202X4_CUSTOM_HEADER: Path to your custom fips202x4.h

Your custom FIPS-202 implementation must impelement the API specified in FIPS202.md.

Notes

• The 4x batched functions (x4) can fall back to 4 sequential calls if batching isn't available
• Structure definitions may differ from mldsa-native's defaults (e.g., for incremental hashing)

Usage

make build   # Build the example
make run     # Run the example

Warning

The randombytes() implementation in test_only_rng/ is for TESTING ONLY. You MUST provide a cryptographically secure RNG for production use.

Footnotes

1. Markku-Juhani O. Saarinen: tiny_sha3, https://github.com/mjosaarinen/tiny_sha3 ↩