| 1 | /********************************************************************* |
| 2 | * Filename: md5.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 MD5 hashing algorithm. |
| 7 | Algorithm specification can be found here: |
| 8 | * http://tools.ietf.org/html/rfc1321 |
| 9 | This implementation uses little endian byte order. |
| 10 | *********************************************************************/ |
| 11 | |
| 12 | /*************************** HEADER FILES ***************************/ |
| 13 | #include <stdlib.h> |
| 14 | #include <string.h> |
| 15 | #include "md5.h" |
| 16 | |
| 17 | /****************************** MACROS ******************************/ |
| 18 | #define ROTLEFT(a,b) ((a << b) | (a >> (32-b))) |
| 19 | |
| 20 | #define F(x,y,z) ((x & y) | (~x & z)) |
| 21 | #define G(x,y,z) ((x & z) | (y & ~z)) |
| 22 | #define H(x,y,z) (x ^ y ^ z) |
| 23 | #define I(x,y,z) (y ^ (x | ~z)) |
| 24 | |
| 25 | #define FF(a,b,c,d,m,s,t) { a += F(b,c,d) + m + t; \ |
| 26 | a = b + ROTLEFT(a,s); } |
| 27 | #define GG(a,b,c,d,m,s,t) { a += G(b,c,d) + m + t; \ |
| 28 | a = b + ROTLEFT(a,s); } |
| 29 | #define HH(a,b,c,d,m,s,t) { a += H(b,c,d) + m + t; \ |
| 30 | a = b + ROTLEFT(a,s); } |
| 31 | #define II(a,b,c,d,m,s,t) { a += I(b,c,d) + m + t; \ |
| 32 | a = b + ROTLEFT(a,s); } |
| 33 | |
| 34 | /*********************** FUNCTION DEFINITIONS ***********************/ |
| 35 | void md5_transform(MD5_CTX *ctx, const BYTE data[]) |
| 36 | { |
| 37 | WORD a, b, c, d, m[16], i, j; |
| 38 | |
| 39 | // MD5 specifies big endian byte order, but this implementation assumes a little |
| 40 | // endian byte order CPU. Reverse all the bytes upon input, and re-reverse them |
| 41 | // on output (in md5_final()). |
| 42 | for (i = 0, j = 0; i < 16; ++i, j += 4) |
| 43 | m[i] = (data[j]) + (data[j + 1] << 8) + (data[j + 2] << 16) + (data[j + 3] << 24); |
| 44 | |
| 45 | a = ctx->state[0]; |
| 46 | b = ctx->state[1]; |
| 47 | c = ctx->state[2]; |
| 48 | d = ctx->state[3]; |
| 49 | |
| 50 | FF(a,b,c,d,m[0], 7,0xd76aa478); |
| 51 | FF(d,a,b,c,m[1], 12,0xe8c7b756); |
| 52 | FF(c,d,a,b,m[2], 17,0x242070db); |
| 53 | FF(b,c,d,a,m[3], 22,0xc1bdceee); |
| 54 | FF(a,b,c,d,m[4], 7,0xf57c0faf); |
| 55 | FF(d,a,b,c,m[5], 12,0x4787c62a); |
| 56 | FF(c,d,a,b,m[6], 17,0xa8304613); |
| 57 | FF(b,c,d,a,m[7], 22,0xfd469501); |
| 58 | FF(a,b,c,d,m[8], 7,0x698098d8); |
| 59 | FF(d,a,b,c,m[9], 12,0x8b44f7af); |
| 60 | FF(c,d,a,b,m[10],17,0xffff5bb1); |
| 61 | FF(b,c,d,a,m[11],22,0x895cd7be); |
| 62 | FF(a,b,c,d,m[12], 7,0x6b901122); |
| 63 | FF(d,a,b,c,m[13],12,0xfd987193); |
| 64 | FF(c,d,a,b,m[14],17,0xa679438e); |
| 65 | FF(b,c,d,a,m[15],22,0x49b40821); |
| 66 | |
| 67 | GG(a,b,c,d,m[1], 5,0xf61e2562); |
| 68 | GG(d,a,b,c,m[6], 9,0xc040b340); |
| 69 | GG(c,d,a,b,m[11],14,0x265e5a51); |
| 70 | GG(b,c,d,a,m[0], 20,0xe9b6c7aa); |
| 71 | GG(a,b,c,d,m[5], 5,0xd62f105d); |
| 72 | GG(d,a,b,c,m[10], 9,0x02441453); |
| 73 | GG(c,d,a,b,m[15],14,0xd8a1e681); |
| 74 | GG(b,c,d,a,m[4], 20,0xe7d3fbc8); |
| 75 | GG(a,b,c,d,m[9], 5,0x21e1cde6); |
| 76 | GG(d,a,b,c,m[14], 9,0xc33707d6); |
| 77 | GG(c,d,a,b,m[3], 14,0xf4d50d87); |
| 78 | GG(b,c,d,a,m[8], 20,0x455a14ed); |
| 79 | GG(a,b,c,d,m[13], 5,0xa9e3e905); |
| 80 | GG(d,a,b,c,m[2], 9,0xfcefa3f8); |
| 81 | GG(c,d,a,b,m[7], 14,0x676f02d9); |
| 82 | GG(b,c,d,a,m[12],20,0x8d2a4c8a); |
| 83 | |
| 84 | HH(a,b,c,d,m[5], 4,0xfffa3942); |
| 85 | HH(d,a,b,c,m[8], 11,0x8771f681); |
| 86 | HH(c,d,a,b,m[11],16,0x6d9d6122); |
| 87 | HH(b,c,d,a,m[14],23,0xfde5380c); |
| 88 | HH(a,b,c,d,m[1], 4,0xa4beea44); |
| 89 | HH(d,a,b,c,m[4], 11,0x4bdecfa9); |
| 90 | HH(c,d,a,b,m[7], 16,0xf6bb4b60); |
| 91 | HH(b,c,d,a,m[10],23,0xbebfbc70); |
| 92 | HH(a,b,c,d,m[13], 4,0x289b7ec6); |
| 93 | HH(d,a,b,c,m[0], 11,0xeaa127fa); |
| 94 | HH(c,d,a,b,m[3], 16,0xd4ef3085); |
| 95 | HH(b,c,d,a,m[6], 23,0x04881d05); |
| 96 | HH(a,b,c,d,m[9], 4,0xd9d4d039); |
| 97 | HH(d,a,b,c,m[12],11,0xe6db99e5); |
| 98 | HH(c,d,a,b,m[15],16,0x1fa27cf8); |
| 99 | HH(b,c,d,a,m[2], 23,0xc4ac5665); |
| 100 | |
| 101 | II(a,b,c,d,m[0], 6,0xf4292244); |
| 102 | II(d,a,b,c,m[7], 10,0x432aff97); |
| 103 | II(c,d,a,b,m[14],15,0xab9423a7); |
| 104 | II(b,c,d,a,m[5], 21,0xfc93a039); |
| 105 | II(a,b,c,d,m[12], 6,0x655b59c3); |
| 106 | II(d,a,b,c,m[3], 10,0x8f0ccc92); |
| 107 | II(c,d,a,b,m[10],15,0xffeff47d); |
| 108 | II(b,c,d,a,m[1], 21,0x85845dd1); |
| 109 | II(a,b,c,d,m[8], 6,0x6fa87e4f); |
| 110 | II(d,a,b,c,m[15],10,0xfe2ce6e0); |
| 111 | II(c,d,a,b,m[6], 15,0xa3014314); |
| 112 | II(b,c,d,a,m[13],21,0x4e0811a1); |
| 113 | II(a,b,c,d,m[4], 6,0xf7537e82); |
| 114 | II(d,a,b,c,m[11],10,0xbd3af235); |
| 115 | II(c,d,a,b,m[2], 15,0x2ad7d2bb); |
| 116 | II(b,c,d,a,m[9], 21,0xeb86d391); |
| 117 | |
| 118 | ctx->state[0] += a; |
| 119 | ctx->state[1] += b; |
| 120 | ctx->state[2] += c; |
| 121 | ctx->state[3] += d; |
| 122 | } |
| 123 | |
| 124 | void md5_init(MD5_CTX *ctx) |
| 125 | { |
| 126 | ctx->datalen = 0; |
| 127 | ctx->bitlen = 0; |
| 128 | ctx->state[0] = 0x67452301; |
| 129 | ctx->state[1] = 0xEFCDAB89; |
| 130 | ctx->state[2] = 0x98BADCFE; |
| 131 | ctx->state[3] = 0x10325476; |
| 132 | } |
| 133 | |
| 134 | void md5_update(MD5_CTX *ctx, const BYTE data[], size_t len) |
| 135 | { |
| 136 | size_t i; |
| 137 | |
| 138 | for (i = 0; i < len; ++i) { |
| 139 | ctx->data[ctx->datalen] = data[i]; |
| 140 | ctx->datalen++; |
| 141 | if (ctx->datalen == 64) { |
| 142 | md5_transform(ctx, ctx->data); |
| 143 | ctx->bitlen += 512; |
| 144 | ctx->datalen = 0; |
| 145 | } |
| 146 | } |
| 147 | } |
| 148 | |
| 149 | void md5_final(MD5_CTX *ctx, BYTE hash[]) |
| 150 | { |
| 151 | size_t i; |
| 152 | |
| 153 | i = ctx->datalen; |
| 154 | |
| 155 | // Pad whatever data is left in the buffer. |
| 156 | if (ctx->datalen < 56) { |
| 157 | ctx->data[i++] = 0x80; |
| 158 | while (i < 56) |
| 159 | ctx->data[i++] = 0x00; |
| 160 | } |
| 161 | else if (ctx->datalen >= 56) { |
| 162 | ctx->data[i++] = 0x80; |
| 163 | while (i < 64) |
| 164 | ctx->data[i++] = 0x00; |
| 165 | md5_transform(ctx, ctx->data); |
| 166 | memset(ctx->data, 0, 56); |
| 167 | } |
| 168 | |
| 169 | // Append to the padding the total message's length in bits and transform. |
| 170 | ctx->bitlen += ctx->datalen * 8; |
| 171 | ctx->data[56] = ctx->bitlen; |
| 172 | ctx->data[57] = ctx->bitlen >> 8; |
| 173 | ctx->data[58] = ctx->bitlen >> 16; |
| 174 | ctx->data[59] = ctx->bitlen >> 24; |
| 175 | ctx->data[60] = ctx->bitlen >> 32; |
| 176 | ctx->data[61] = ctx->bitlen >> 40; |
| 177 | ctx->data[62] = ctx->bitlen >> 48; |
| 178 | ctx->data[63] = ctx->bitlen >> 56; |
| 179 | md5_transform(ctx, ctx->data); |
| 180 | |
| 181 | // Since this implementation uses little endian byte ordering and MD uses big endian, |
| 182 | // reverse all the bytes when copying the final state to the output hash. |
| 183 | for (i = 0; i < 4; ++i) { |
| 184 | hash[i] = (ctx->state[0] >> (i * 8)) & 0x000000ff; |
| 185 | hash[i + 4] = (ctx->state[1] >> (i * 8)) & 0x000000ff; |
| 186 | hash[i + 8] = (ctx->state[2] >> (i * 8)) & 0x000000ff; |
| 187 | hash[i + 12] = (ctx->state[3] >> (i * 8)) & 0x000000ff; |
| 188 | } |
| 189 | } |