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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 | } |