Merge pull request #7 from make-software/checksum

Checksum

Author: Roman Bylbas

composer.json

@@ -13,7 +13,6 @@
     "ext-sodium": "*",
     "ext-gmp": "*",
     "ext-mbstring": "*",
-    "deemru/blake2b": "^1.0",
     "mdanter/ecc": "^1.0",
     "ionux/phactor": "1.0.8"
   },

composer.lock

@@ -0,0 +1,113 @@
+<?php
+
+namespace Casper\Util;
+
+class CEP57ChecksumUtil
+{
+    private const BLAKE2B_HASH_LENGTH = 64;
+    private const HEX_CHARS = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'];
+
+    /**
+     * @param string $hex
+     * @return bool
+     *
+     * @throws \Exception
+     */
+    public static function hasChecksum(string $hex): bool
+    {
+        $mix = 0;
+
+        foreach (str_split($hex) as $char) {
+            if ($char >= '0' && $char <= '9') {
+                $mix |= 0x00;
+            }
+            elseif ($char >= 'a' && $char <= 'f') {
+                $mix |= 0x01;
+            }
+            elseif ($char >= 'A' && $char <= 'F') {
+                $mix |= 0x02;
+            }
+            else {
+                throw new \Exception('Input is not an hexadecimal string');
+            }
+        }
+
+        return $mix > 2;
+    }
+
+    /**
+     * @param array $bytes
+     * @return string
+     *
+     * @throws \Exception
+     */
+    public static function encode(array $bytes): string
+    {
+        $nibbles = self::byteToNibbles($bytes);
+        $hashBits = self::bytesToBitsCycle(HashUtil::blake2bHash($bytes, self::BLAKE2B_HASH_LENGTH));
+
+        $bitIndex = 0;
+        foreach ($nibbles as $nibble) {
+            $char = self::HEX_CHARS[$nibble];
+            $result[] = ($char >= 'a' && $char <= 'f') && $hashBits[$bitIndex++]
+                ? strtoupper($char)
+                : $char;
+        }
+
+        return implode($result ?? []);
+    }
+
+    /**
+     * @param string $hex
+     * @return array
+     *
+     * @throws \Exception
+     */
+    public static function decode(string $hex): array
+    {
+        $bytes = ByteUtil::hexToByteArray($hex);
+
+        if (!self::hasChecksum($hex)) {
+            return $bytes;
+        }
+
+        $encoded = self::encode($bytes);
+
+        if ($encoded !== $hex) {
+            throw new \Exception('Invalid checksum');
+        }
+
+        return $bytes;
+    }
+
+    /**
+     * @param array $bytes
+     * @return int[]
+     *
+     * @throws \Exception
+     */
+    private static function byteToNibbles(array $bytes): array
+    {
+        foreach ($bytes as $byte) {
+            $nibbles[] = $byte >> 4;
+            $nibbles[] = $byte & 0x0F;
+        }
+
+        return $nibbles;
+    }
+
+    /**
+     * @param array $bytes
+     * @return int[]
+     */
+    private static function bytesToBitsCycle(array $bytes): array
+    {
+        for ($i = 0; $i < count($bytes); $i++) {
+            for ($j = 0; $j < 8; $j++) {
+                $bits[] = ($bytes[$i] >> $j) & 0x01;
+            }
+        }
+
+        return $bits;
+    }
+}

src/Util/CEP57ChecksumUtil.php

@@ -2,28 +2,22 @@
 
 namespace Casper\Util;
 
-use deemru\Blake2b;
-
 class HashUtil
 {
-    private static Blake2b $blake2b;
-
     /**
      * @param int[]
+     * @param int $length
      * @return int[]
      *
-     * @throws \Exception
+     * @throws \SodiumException
      */
-    public static function blake2bHash(array $bytes): array
+    public static function blake2bHash(array $bytes, int $length = 32): array
     {
-        if (!isset(self::$blake2b)) {
-            self::$blake2b = new Blake2b();
-        }
+        $hashState = sodium_crypto_generichash_init('', $length);
+        sodium_crypto_generichash_update($hashState, ByteUtil::byteArrayToString($bytes));
 
         return ByteUtil::stringToByteArray(
-            self::$blake2b->hash(
-                ByteUtil::byteArrayToString($bytes)
-            )
+            sodium_crypto_generichash_final($hashState, $length)
         );
     }
 }

src/Util/HashUtil.php

@@ -0,0 +1,47 @@
+<?php
+
+namespace Tests\Functional\Util;
+
+use PHPUnit\Framework\TestCase;
+
+use Casper\Util\ByteUtil;
+use Casper\Util\CEP57ChecksumUtil;
+
+class CEP57ChecksumUtilTest extends TestCase
+{
+    /**
+     * @throws \Exception
+     */
+    public function testHasCheckSum(): void
+    {
+        $hexWithCheckSum = 'de8649985929090b7CB225e35a5A7B4087fb8fcB3D18C8C9a58DA68e4edA8a2E';
+        $this->assertTrue(CEP57ChecksumUtil::hasChecksum($hexWithCheckSum));
+
+        $hexWithoutCheckSum = 'de8649985929090b7cb225e35a5a7b4087fb8fcb3d18c8c9a58da68e4eda8a2e';
+        $this->assertFalse(CEP57ChecksumUtil::hasChecksum($hexWithoutCheckSum));
+    }
+
+    /**
+     * @throws \Exception
+     */
+    public function testEncode(): void
+    {
+        $hex = 'de8649985929090b7CB225e35a5A7B4087fb8fcB3D18C8C9a58DA68e4edA8a2E';
+        $bytes = ByteUtil::hexToByteArray($hex);
+
+        $encodedHex = CEP57ChecksumUtil::encode($bytes);
+        $this->assertEquals($hex, $encodedHex);
+    }
+
+    /**
+     * @throws \Exception
+     */
+    public function testDecode(): void
+    {
+        $hex = 'de8649985929090b7CB225e35a5A7B4087fb8fcB3D18C8C9a58DA68e4edA8a2E';
+
+        $decodedByteArray = CEP57ChecksumUtil::decode($hex);
+        $this->assertIsArray($decodedByteArray);
+        $this->assertCount(32, $decodedByteArray);
+    }
+}