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bconSha256.c (5263B)
1 /********************************************************************* 2 * Filename: sha256.c 3 * Author: Brad Conte (brad AT bradconte.com) 4 * Copyright: 5 * Disclaimer: This code is presented "as is" without any guarantees. 6 * Details: Implementation of the SHA-256 hashing algorithm. 7 SHA-256 is one of the three algorithms in the SHA2 8 specification. The others, SHA-384 and SHA-512, are not 9 offered in this implementation. 10 Algorithm specification can be found here: 11 * http://csrc.nist.gov/publications/fips/fips180-2/fips180-2withchangenotice.pdf 12 This implementation uses little endian byte order. 13 *********************************************************************/ 14 15 /*************************** HEADER FILES ***************************/ 16 #include <stdlib.h> 17 #include <memory.h> 18 #include "sha256.h" 19 20 /****************************** MACROS ******************************/ 21 #define ROTLEFT(a,b) (((a) << (b)) | ((a) >> (32-(b)))) 22 #define ROTRIGHT(a,b) (((a) >> (b)) | ((a) << (32-(b)))) 23 24 #define CH(x,y,z) (((x) & (y)) ^ (~(x) & (z))) 25 #define MAJ(x,y,z) (((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z))) 26 #define EP0(x) (ROTRIGHT(x,2) ^ ROTRIGHT(x,13) ^ ROTRIGHT(x,22)) 27 #define EP1(x) (ROTRIGHT(x,6) ^ ROTRIGHT(x,11) ^ ROTRIGHT(x,25)) 28 #define SIG0(x) (ROTRIGHT(x,7) ^ ROTRIGHT(x,18) ^ ((x) >> 3)) 29 #define SIG1(x) (ROTRIGHT(x,17) ^ ROTRIGHT(x,19) ^ ((x) >> 10)) 30 31 /**************************** VARIABLES *****************************/ 32 static const WORD k[64] = { 33 0x428a2f98,0x71374491,0xb5c0fbcf,0xe9b5dba5,0x3956c25b,0x59f111f1,0x923f82a4,0xab1c5ed5, 34 0xd807aa98,0x12835b01,0x243185be,0x550c7dc3,0x72be5d74,0x80deb1fe,0x9bdc06a7,0xc19bf174, 35 0xe49b69c1,0xefbe4786,0x0fc19dc6,0x240ca1cc,0x2de92c6f,0x4a7484aa,0x5cb0a9dc,0x76f988da, 36 0x983e5152,0xa831c66d,0xb00327c8,0xbf597fc7,0xc6e00bf3,0xd5a79147,0x06ca6351,0x14292967, 37 0x27b70a85,0x2e1b2138,0x4d2c6dfc,0x53380d13,0x650a7354,0x766a0abb,0x81c2c92e,0x92722c85, 38 0xa2bfe8a1,0xa81a664b,0xc24b8b70,0xc76c51a3,0xd192e819,0xd6990624,0xf40e3585,0x106aa070, 39 0x19a4c116,0x1e376c08,0x2748774c,0x34b0bcb5,0x391c0cb3,0x4ed8aa4a,0x5b9cca4f,0x682e6ff3, 40 0x748f82ee,0x78a5636f,0x84c87814,0x8cc70208,0x90befffa,0xa4506ceb,0xbef9a3f7,0xc67178f2 41 }; 42 43 /*********************** FUNCTION DEFINITIONS ***********************/ 44 void sha256_transform(SHA256_CTX *ctx, const BYTE data[]) 45 { 46 WORD a, b, c, d, e, f, g, h, i, j, t1, t2, m[64]; 47 48 for (i = 0, j = 0; i < 16; ++i, j += 4) 49 m[i] = (data[j] << 24) | (data[j + 1] << 16) | (data[j + 2] << 8) | (data[j + 3]); 50 for ( ; i < 64; ++i) 51 m[i] = SIG1(m[i - 2]) + m[i - 7] + SIG0(m[i - 15]) + m[i - 16]; 52 53 a = ctx->state[0]; 54 b = ctx->state[1]; 55 c = ctx->state[2]; 56 d = ctx->state[3]; 57 e = ctx->state[4]; 58 f = ctx->state[5]; 59 g = ctx->state[6]; 60 h = ctx->state[7]; 61 62 for (i = 0; i < 64; ++i) { 63 t1 = h + EP1(e) + CH(e,f,g) + k[i] + m[i]; 64 t2 = EP0(a) + MAJ(a,b,c); 65 h = g; 66 g = f; 67 f = e; 68 e = d + t1; 69 d = c; 70 c = b; 71 b = a; 72 a = t1 + t2; 73 } 74 75 ctx->state[0] += a; 76 ctx->state[1] += b; 77 ctx->state[2] += c; 78 ctx->state[3] += d; 79 ctx->state[4] += e; 80 ctx->state[5] += f; 81 ctx->state[6] += g; 82 ctx->state[7] += h; 83 } 84 85 void sha256_init(SHA256_CTX *ctx) 86 { 87 ctx->datalen = 0; 88 ctx->bitlen = 0; 89 ctx->state[0] = 0x6a09e667; 90 ctx->state[1] = 0xbb67ae85; 91 ctx->state[2] = 0x3c6ef372; 92 ctx->state[3] = 0xa54ff53a; 93 ctx->state[4] = 0x510e527f; 94 ctx->state[5] = 0x9b05688c; 95 ctx->state[6] = 0x1f83d9ab; 96 ctx->state[7] = 0x5be0cd19; 97 } 98 99 void sha256_update(SHA256_CTX *ctx, const BYTE data[], size_t len) 100 { 101 WORD i; 102 103 for (i = 0; i < len; ++i) { 104 ctx->data[ctx->datalen] = data[i]; 105 ctx->datalen++; 106 if (ctx->datalen == 64) { 107 sha256_transform(ctx, ctx->data); 108 ctx->bitlen += 512; 109 ctx->datalen = 0; 110 } 111 } 112 } 113 114 void sha256_final(SHA256_CTX *ctx, BYTE hash[]) 115 { 116 WORD i; 117 118 i = ctx->datalen; 119 120 // Pad whatever data is left in the buffer. 121 if (ctx->datalen < 56) { 122 ctx->data[i++] = 0x80; 123 while (i < 56) 124 ctx->data[i++] = 0x00; 125 } 126 else { 127 ctx->data[i++] = 0x80; 128 while (i < 64) 129 ctx->data[i++] = 0x00; 130 sha256_transform(ctx, ctx->data); 131 memset(ctx->data, 0, 56); 132 } 133 134 // Append to the padding the total message's length in bits and transform. 135 ctx->bitlen += ctx->datalen * 8; 136 ctx->data[63] = ctx->bitlen; 137 ctx->data[62] = ctx->bitlen >> 8; 138 ctx->data[61] = ctx->bitlen >> 16; 139 ctx->data[60] = ctx->bitlen >> 24; 140 ctx->data[59] = ctx->bitlen >> 32; 141 ctx->data[58] = ctx->bitlen >> 40; 142 ctx->data[57] = ctx->bitlen >> 48; 143 ctx->data[56] = ctx->bitlen >> 56; 144 sha256_transform(ctx, ctx->data); 145 146 // Since this implementation uses little endian byte ordering and SHA uses big endian, 147 // reverse all the bytes when copying the final state to the output hash. 148 for (i = 0; i < 4; ++i) { 149 hash[i] = (ctx->state[0] >> (24 - i * 8)) & 0x000000ff; 150 hash[i + 4] = (ctx->state[1] >> (24 - i * 8)) & 0x000000ff; 151 hash[i + 8] = (ctx->state[2] >> (24 - i * 8)) & 0x000000ff; 152 hash[i + 12] = (ctx->state[3] >> (24 - i * 8)) & 0x000000ff; 153 hash[i + 16] = (ctx->state[4] >> (24 - i * 8)) & 0x000000ff; 154 hash[i + 20] = (ctx->state[5] >> (24 - i * 8)) & 0x000000ff; 155 hash[i + 24] = (ctx->state[6] >> (24 - i * 8)) & 0x000000ff; 156 hash[i + 28] = (ctx->state[7] >> (24 - i * 8)) & 0x000000ff; 157 } 158 }