using System.Runtime.CompilerServices; namespace WhiteRabbit { /** * Code taken from BouncyCastle and optimized for specific constraints (e.g. input is always larger than 4 bytes and smaller than 52 bytes). * Further optimization: input could be assumed to be smaller than 27 bytes (original phrase contains 18 letters, so that allows anagrams of 9 words) * base implementation of MD4 family style digest as outlined in * "Handbook of Applied Cryptography", pages 344 - 347. * implementation of MD5 as outlined in "Handbook of Applied Cryptography", pages 346 - 347. */ internal static class MD5Digest { [MethodImpl(MethodImplOptions.AggressiveInlining)] public static unsafe uint[] Compute(Phrase input) { uint a = 0x67452301; uint b = 0xefcdab89; uint c = 0x98badcfe; uint d = 0x10325476; a = b + LeftRotate(0xd76aa478 + a + Blend(d, c, b) + input.Buffer[0], 7); d = a + LeftRotate(0xe8c7b756 + d + Blend(c, b, a) + input.Buffer[1], 12); c = d + LeftRotate(0x242070db + c + Blend(b, a, d) + input.Buffer[2], 17); b = c + LeftRotate(0xc1bdceee + b + Blend(a, d, c) + input.Buffer[3], 22); a = b + LeftRotate(0xf57c0faf + a + Blend(d, c, b) + input.Buffer[4], 7); d = a + LeftRotate(0x4787c62a + d + Blend(c, b, a) + input.Buffer[5], 12); c = d + LeftRotate(0xa8304613 + c + Blend(b, a, d) + input.Buffer[6], 17); b = c + LeftRotate(0xfd469501 + b + Blend(a, d, c), 22); a = b + LeftRotate(0x698098d8 + a + Blend(d, c, b), 7); d = a + LeftRotate(0x8b44f7af + d + Blend(c, b, a), 12); c = d + LeftRotate(0xffff5bb1 + c + Blend(b, a, d), 17); b = c + LeftRotate(0x895cd7be + b + Blend(a, d, c), 22); a = b + LeftRotate(0x6b901122 + a + Blend(d, c, b), 7); d = a + LeftRotate(0xfd987193 + d + Blend(c, b, a), 12); c = d + LeftRotate(0xa679438e + c + Blend(b, a, d) + input.Buffer[7], 17); b = c + LeftRotate(0x49b40821 + b + Blend(a, d, c), 22); a = b + LeftRotate(0xf61e2562 + a + Blend(c, b, d) + input.Buffer[1], 5); d = a + LeftRotate(0xc040b340 + d + Blend(b, a, c) + input.Buffer[6], 9); c = d + LeftRotate(0x265e5a51 + c + Blend(a, d, b), 14); b = c + LeftRotate(0xe9b6c7aa + b + Blend(d, c, a) + input.Buffer[0], 20); a = b + LeftRotate(0xd62f105d + a + Blend(c, b, d) + input.Buffer[5], 5); d = a + LeftRotate(0x02441453 + d + Blend(b, a, c), 9); c = d + LeftRotate(0xd8a1e681 + c + Blend(a, d, b), 14); b = c + LeftRotate(0xe7d3fbc8 + b + Blend(d, c, a) + input.Buffer[4], 20); a = b + LeftRotate(0x21e1cde6 + a + Blend(c, b, d), 5); d = a + LeftRotate(0xc33707d6 + d + Blend(b, a, c) + input.Buffer[7], 9); c = d + LeftRotate(0xf4d50d87 + c + Blend(a, d, b) + input.Buffer[3], 14); b = c + LeftRotate(0x455a14ed + b + Blend(d, c, a), 20); a = b + LeftRotate(0xa9e3e905 + a + Blend(c, b, d), 5); d = a + LeftRotate(0xfcefa3f8 + d + Blend(b, a, c) + input.Buffer[2], 9); c = d + LeftRotate(0x676f02d9 + c + Blend(a, d, b), 14); b = c + LeftRotate(0x8d2a4c8a + b + Blend(d, c, a), 20); a = b + LeftRotate(0xfffa3942 + a + Xor(b, c, d) + input.Buffer[5], 4); d = a + LeftRotate(0x8771f681 + d + Xor(a, b, c), 11); c = d + LeftRotate(0x6d9d6122 + c + Xor(d, a, b), 16); b = c + LeftRotate(0xfde5380c + b + Xor(c, d, a) + input.Buffer[7], 23); a = b + LeftRotate(0xa4beea44 + a + Xor(b, c, d) + input.Buffer[1], 4); d = a + LeftRotate(0x4bdecfa9 + d + Xor(a, b, c) + input.Buffer[4], 11); c = d + LeftRotate(0xf6bb4b60 + c + Xor(d, a, b), 16); b = c + LeftRotate(0xbebfbc70 + b + Xor(c, d, a), 23); a = b + LeftRotate(0x289b7ec6 + a + Xor(b, c, d), 4); d = a + LeftRotate(0xeaa127fa + d + Xor(a, b, c) + input.Buffer[0], 11); c = d + LeftRotate(0xd4ef3085 + c + Xor(d, a, b) + input.Buffer[3], 16); b = c + LeftRotate(0x04881d05 + b + Xor(c, d, a) + input.Buffer[6], 23); a = b + LeftRotate(0xd9d4d039 + a + Xor(b, c, d), 4); d = a + LeftRotate(0xe6db99e5 + d + Xor(a, b, c), 11); c = d + LeftRotate(0x1fa27cf8 + c + Xor(d, a, b), 16); b = c + LeftRotate(0xc4ac5665 + b + Xor(c, d, a) + input.Buffer[2], 23); a = b + LeftRotate(0xf4292244 + a + I(c, b, d) + input.Buffer[0], 6); d = a + LeftRotate(0x432aff97 + d + I(b, a, c), 10); c = d + LeftRotate(0xab9423a7 + c + I(a, d, b) + input.Buffer[7], 15); b = c + LeftRotate(0xfc93a039 + b + I(d, c, a) + input.Buffer[5], 21); a = b + LeftRotate(0x655b59c3 + a + I(c, b, d), 6); d = a + LeftRotate(0x8f0ccc92 + d + I(b, a, c) + input.Buffer[3], 10); c = d + LeftRotate(0xffeff47d + c + I(a, d, b), 15); b = c + LeftRotate(0x85845dd1 + b + I(d, c, a) + input.Buffer[1], 21); a = b + LeftRotate(0x6fa87e4f + a + I(c, b, d), 6); d = a + LeftRotate(0xfe2ce6e0 + d + I(b, a, c), 10); c = d + LeftRotate(0xa3014314 + c + I(a, d, b) + input.Buffer[6], 15); b = c + LeftRotate(0x4e0811a1 + b + I(d, c, a), 21); a = b + LeftRotate(0xf7537e82 + a + I(c, b, d) + input.Buffer[4], 6); d = a + LeftRotate(0xbd3af235 + d + I(b, a, c), 10); c = d + LeftRotate(0x2ad7d2bb + c + I(a, d, b) + input.Buffer[2], 15); b = c + LeftRotate(0xeb86d391 + b + I(d, c, a), 21); return new[] { 0x67452301 + a, 0xefcdab89 + b, 0x98badcfe + c, 0x10325476 + d, }; } [MethodImpl(MethodImplOptions.AggressiveInlining)] private static uint Blend(uint a, uint b, uint x) { return (x & b) | (~x & a); } [MethodImpl(MethodImplOptions.AggressiveInlining)] private static uint Xor(uint a, uint b, uint c) { return a ^ b ^ c; } [MethodImpl(MethodImplOptions.AggressiveInlining)] private static uint I(uint a, uint b, uint c) { return a ^ (b | ~c); } [MethodImpl(MethodImplOptions.AggressiveInlining)] private static uint LeftRotate(uint x, int left) { return (x << left) | (x >> 32 - left); } } }