# B-Con/crypto-algorithms

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02b66ec Sep 13, 2012
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 /********************************************************************* * Filename: sha256.c * Author: Brad Conte (brad AT bradconte.com) * Copyright: * Disclaimer: This code is presented "as is" without any guarantees. * Details: Implementation of the SHA-256 hashing algorithm. SHA-256 is one of the three algorithms in the SHA2 specification. The others, SHA-384 and SHA-512, are not offered in this implementation. Algorithm specification can be found here: * http://csrc.nist.gov/publications/fips/fips180-2/fips180-2withchangenotice.pdf This implementation uses little endian byte order. *********************************************************************/ /*************************** HEADER FILES ***************************/ #include #include #include "sha256.h" /****************************** MACROS ******************************/ #define ROTLEFT(a,b) (((a) << (b)) | ((a) >> (32-(b)))) #define ROTRIGHT(a,b) (((a) >> (b)) | ((a) << (32-(b)))) #define CH(x,y,z) (((x) & (y)) ^ (~(x) & (z))) #define MAJ(x,y,z) (((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z))) #define EP0(x) (ROTRIGHT(x,2) ^ ROTRIGHT(x,13) ^ ROTRIGHT(x,22)) #define EP1(x) (ROTRIGHT(x,6) ^ ROTRIGHT(x,11) ^ ROTRIGHT(x,25)) #define SIG0(x) (ROTRIGHT(x,7) ^ ROTRIGHT(x,18) ^ ((x) >> 3)) #define SIG1(x) (ROTRIGHT(x,17) ^ ROTRIGHT(x,19) ^ ((x) >> 10)) /**************************** VARIABLES *****************************/ static const WORD k[64] = { 0x428a2f98,0x71374491,0xb5c0fbcf,0xe9b5dba5,0x3956c25b,0x59f111f1,0x923f82a4,0xab1c5ed5, 0xd807aa98,0x12835b01,0x243185be,0x550c7dc3,0x72be5d74,0x80deb1fe,0x9bdc06a7,0xc19bf174, 0xe49b69c1,0xefbe4786,0x0fc19dc6,0x240ca1cc,0x2de92c6f,0x4a7484aa,0x5cb0a9dc,0x76f988da, 0x983e5152,0xa831c66d,0xb00327c8,0xbf597fc7,0xc6e00bf3,0xd5a79147,0x06ca6351,0x14292967, 0x27b70a85,0x2e1b2138,0x4d2c6dfc,0x53380d13,0x650a7354,0x766a0abb,0x81c2c92e,0x92722c85, 0xa2bfe8a1,0xa81a664b,0xc24b8b70,0xc76c51a3,0xd192e819,0xd6990624,0xf40e3585,0x106aa070, 0x19a4c116,0x1e376c08,0x2748774c,0x34b0bcb5,0x391c0cb3,0x4ed8aa4a,0x5b9cca4f,0x682e6ff3, 0x748f82ee,0x78a5636f,0x84c87814,0x8cc70208,0x90befffa,0xa4506ceb,0xbef9a3f7,0xc67178f2 }; /*********************** FUNCTION DEFINITIONS ***********************/ void sha256_transform(SHA256_CTX *ctx, const BYTE data[]) { WORD a, b, c, d, e, f, g, h, i, j, t1, t2, m[64]; for (i = 0, j = 0; i < 16; ++i, j += 4) m[i] = (data[j] << 24) | (data[j + 1] << 16) | (data[j + 2] << 8) | (data[j + 3]); for ( ; i < 64; ++i) m[i] = SIG1(m[i - 2]) + m[i - 7] + SIG0(m[i - 15]) + m[i - 16]; a = ctx->state[0]; b = ctx->state[1]; c = ctx->state[2]; d = ctx->state[3]; e = ctx->state[4]; f = ctx->state[5]; g = ctx->state[6]; h = ctx->state[7]; for (i = 0; i < 64; ++i) { t1 = h + EP1(e) + CH(e,f,g) + k[i] + m[i]; t2 = EP0(a) + MAJ(a,b,c); h = g; g = f; f = e; e = d + t1; d = c; c = b; b = a; a = t1 + t2; } ctx->state[0] += a; ctx->state[1] += b; ctx->state[2] += c; ctx->state[3] += d; ctx->state[4] += e; ctx->state[5] += f; ctx->state[6] += g; ctx->state[7] += h; } void sha256_init(SHA256_CTX *ctx) { ctx->datalen = 0; ctx->bitlen = 0; ctx->state[0] = 0x6a09e667; ctx->state[1] = 0xbb67ae85; ctx->state[2] = 0x3c6ef372; ctx->state[3] = 0xa54ff53a; ctx->state[4] = 0x510e527f; ctx->state[5] = 0x9b05688c; ctx->state[6] = 0x1f83d9ab; ctx->state[7] = 0x5be0cd19; } void sha256_update(SHA256_CTX *ctx, const BYTE data[], size_t len) { WORD i; for (i = 0; i < len; ++i) { ctx->data[ctx->datalen] = data[i]; ctx->datalen++; if (ctx->datalen == 64) { sha256_transform(ctx, ctx->data); ctx->bitlen += 512; ctx->datalen = 0; } } } void sha256_final(SHA256_CTX *ctx, BYTE hash[]) { WORD i; i = ctx->datalen; // Pad whatever data is left in the buffer. if (ctx->datalen < 56) { ctx->data[i++] = 0x80; while (i < 56) ctx->data[i++] = 0x00; } else { ctx->data[i++] = 0x80; while (i < 64) ctx->data[i++] = 0x00; sha256_transform(ctx, ctx->data); memset(ctx->data, 0, 56); } // Append to the padding the total message's length in bits and transform. ctx->bitlen += ctx->datalen * 8; ctx->data[63] = ctx->bitlen; ctx->data[62] = ctx->bitlen >> 8; ctx->data[61] = ctx->bitlen >> 16; ctx->data[60] = ctx->bitlen >> 24; ctx->data[59] = ctx->bitlen >> 32; ctx->data[58] = ctx->bitlen >> 40; ctx->data[57] = ctx->bitlen >> 48; ctx->data[56] = ctx->bitlen >> 56; sha256_transform(ctx, ctx->data); // Since this implementation uses little endian byte ordering and SHA uses big endian, // reverse all the bytes when copying the final state to the output hash. for (i = 0; i < 4; ++i) { hash[i] = (ctx->state[0] >> (24 - i * 8)) & 0x000000ff; hash[i + 4] = (ctx->state[1] >> (24 - i * 8)) & 0x000000ff; hash[i + 8] = (ctx->state[2] >> (24 - i * 8)) & 0x000000ff; hash[i + 12] = (ctx->state[3] >> (24 - i * 8)) & 0x000000ff; hash[i + 16] = (ctx->state[4] >> (24 - i * 8)) & 0x000000ff; hash[i + 20] = (ctx->state[5] >> (24 - i * 8)) & 0x000000ff; hash[i + 24] = (ctx->state[6] >> (24 - i * 8)) & 0x000000ff; hash[i + 28] = (ctx->state[7] >> (24 - i * 8)) & 0x000000ff; } }