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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 }