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1 /* | |
2 * This code implements the MD5 message-digest algorithm. | |
3 * The algorithm is due to Ron Rivest. This code was | |
4 * written by Colin Plumb in 1993, no copyright is claimed. | |
5 * This code is in the public domain; do with it what you wish. | |
6 * | |
7 * Equivalent code is available from RSA Data Security, Inc. | |
8 * This code has been tested against that, and is equivalent, | |
9 * except that you don't need to include two pages of legalese | |
10 * with every copy. | |
11 * | |
12 * To compute the message digest of a chunk of bytes, declare an | |
13 * MD5Context structure, pass it to MD5Init, call MD5Update as | |
14 * needed on buffers full of bytes, and then call MD5Final, which | |
15 * will fill a supplied 16-byte array with the digest. | |
16 */ | |
17 | |
18 // Changes from original C code: | |
19 // Ported to C++, type casting, Google code style. | |
20 | |
21 #include "webrtc/base/md5.h" | |
22 | |
23 // TODO: Avoid memcmpy - hash directly from memory. | |
24 #include <string.h> // for memcpy(). | |
25 | |
26 #include "webrtc/base/byteorder.h" // for RTC_ARCH_CPU_LITTLE_ENDIAN. | |
27 | |
28 namespace rtc { | |
29 | |
30 #ifdef RTC_ARCH_CPU_LITTLE_ENDIAN | |
31 #define ByteReverse(buf, len) // Nothing. | |
32 #else // RTC_ARCH_CPU_BIG_ENDIAN | |
33 static void ByteReverse(uint32_t* buf, int len) { | |
34 for (int i = 0; i < len; ++i) { | |
35 buf[i] = rtc::GetLE32(&buf[i]); | |
36 } | |
37 } | |
38 #endif | |
39 | |
40 // Start MD5 accumulation. Set bit count to 0 and buffer to mysterious | |
41 // initialization constants. | |
42 void MD5Init(MD5Context* ctx) { | |
43 ctx->buf[0] = 0x67452301; | |
44 ctx->buf[1] = 0xefcdab89; | |
45 ctx->buf[2] = 0x98badcfe; | |
46 ctx->buf[3] = 0x10325476; | |
47 ctx->bits[0] = 0; | |
48 ctx->bits[1] = 0; | |
49 } | |
50 | |
51 // Update context to reflect the concatenation of another buffer full of bytes. | |
52 void MD5Update(MD5Context* ctx, const uint8_t* buf, size_t len) { | |
53 // Update bitcount. | |
54 uint32_t t = ctx->bits[0]; | |
55 if ((ctx->bits[0] = t + (static_cast<uint32_t>(len) << 3)) < t) { | |
56 ctx->bits[1]++; // Carry from low to high. | |
57 } | |
58 ctx->bits[1] += static_cast<uint32_t>(len >> 29); | |
59 t = (t >> 3) & 0x3f; // Bytes already in shsInfo->data. | |
60 | |
61 // Handle any leading odd-sized chunks. | |
62 if (t) { | |
63 uint8_t* p = reinterpret_cast<uint8_t*>(ctx->in) + t; | |
64 | |
65 t = 64-t; | |
66 if (len < t) { | |
67 memcpy(p, buf, len); | |
68 return; | |
69 } | |
70 memcpy(p, buf, t); | |
71 ByteReverse(ctx->in, 16); | |
72 MD5Transform(ctx->buf, ctx->in); | |
73 buf += t; | |
74 len -= t; | |
75 } | |
76 | |
77 // Process data in 64-byte chunks. | |
78 while (len >= 64) { | |
79 memcpy(ctx->in, buf, 64); | |
80 ByteReverse(ctx->in, 16); | |
81 MD5Transform(ctx->buf, ctx->in); | |
82 buf += 64; | |
83 len -= 64; | |
84 } | |
85 | |
86 // Handle any remaining bytes of data. | |
87 memcpy(ctx->in, buf, len); | |
88 } | |
89 | |
90 // Final wrapup - pad to 64-byte boundary with the bit pattern. | |
91 // 1 0* (64-bit count of bits processed, MSB-first) | |
92 void MD5Final(MD5Context* ctx, uint8_t digest[16]) { | |
93 // Compute number of bytes mod 64. | |
94 uint32_t count = (ctx->bits[0] >> 3) & 0x3F; | |
95 | |
96 // Set the first char of padding to 0x80. This is safe since there is | |
97 // always at least one byte free. | |
98 uint8_t* p = reinterpret_cast<uint8_t*>(ctx->in) + count; | |
99 *p++ = 0x80; | |
100 | |
101 // Bytes of padding needed to make 64 bytes. | |
102 count = 64 - 1 - count; | |
103 | |
104 // Pad out to 56 mod 64. | |
105 if (count < 8) { | |
106 // Two lots of padding: Pad the first block to 64 bytes. | |
107 memset(p, 0, count); | |
108 ByteReverse(ctx->in, 16); | |
109 MD5Transform(ctx->buf, ctx->in); | |
110 | |
111 // Now fill the next block with 56 bytes. | |
112 memset(ctx->in, 0, 56); | |
113 } else { | |
114 // Pad block to 56 bytes. | |
115 memset(p, 0, count - 8); | |
116 } | |
117 ByteReverse(ctx->in, 14); | |
118 | |
119 // Append length in bits and transform. | |
120 ctx->in[14] = ctx->bits[0]; | |
121 ctx->in[15] = ctx->bits[1]; | |
122 | |
123 MD5Transform(ctx->buf, ctx->in); | |
124 ByteReverse(ctx->buf, 4); | |
125 memcpy(digest, ctx->buf, 16); | |
126 memset(ctx, 0, sizeof(*ctx)); // In case it's sensitive. | |
127 } | |
128 | |
129 // The four core functions - F1 is optimized somewhat. | |
130 // #define F1(x, y, z) (x & y | ~x & z) | |
131 #define F1(x, y, z) (z ^ (x & (y ^ z))) | |
132 #define F2(x, y, z) F1(z, x, y) | |
133 #define F3(x, y, z) (x ^ y ^ z) | |
134 #define F4(x, y, z) (y ^ (x | ~z)) | |
135 | |
136 // This is the central step in the MD5 algorithm. | |
137 #define MD5STEP(f, w, x, y, z, data, s) \ | |
138 (w += f(x, y, z) + data, w = w << s | w >> (32 - s), w += x) | |
139 | |
140 // The core of the MD5 algorithm, this alters an existing MD5 hash to | |
141 // reflect the addition of 16 longwords of new data. MD5Update blocks | |
142 // the data and converts bytes into longwords for this routine. | |
143 void MD5Transform(uint32_t buf[4], const uint32_t in[16]) { | |
144 uint32_t a = buf[0]; | |
145 uint32_t b = buf[1]; | |
146 uint32_t c = buf[2]; | |
147 uint32_t d = buf[3]; | |
148 | |
149 MD5STEP(F1, a, b, c, d, in[ 0] + 0xd76aa478, 7); | |
150 MD5STEP(F1, d, a, b, c, in[ 1] + 0xe8c7b756, 12); | |
151 MD5STEP(F1, c, d, a, b, in[ 2] + 0x242070db, 17); | |
152 MD5STEP(F1, b, c, d, a, in[ 3] + 0xc1bdceee, 22); | |
153 MD5STEP(F1, a, b, c, d, in[ 4] + 0xf57c0faf, 7); | |
154 MD5STEP(F1, d, a, b, c, in[ 5] + 0x4787c62a, 12); | |
155 MD5STEP(F1, c, d, a, b, in[ 6] + 0xa8304613, 17); | |
156 MD5STEP(F1, b, c, d, a, in[ 7] + 0xfd469501, 22); | |
157 MD5STEP(F1, a, b, c, d, in[ 8] + 0x698098d8, 7); | |
158 MD5STEP(F1, d, a, b, c, in[ 9] + 0x8b44f7af, 12); | |
159 MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17); | |
160 MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22); | |
161 MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7); | |
162 MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12); | |
163 MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17); | |
164 MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22); | |
165 | |
166 MD5STEP(F2, a, b, c, d, in[ 1] + 0xf61e2562, 5); | |
167 MD5STEP(F2, d, a, b, c, in[ 6] + 0xc040b340, 9); | |
168 MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14); | |
169 MD5STEP(F2, b, c, d, a, in[ 0] + 0xe9b6c7aa, 20); | |
170 MD5STEP(F2, a, b, c, d, in[ 5] + 0xd62f105d, 5); | |
171 MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9); | |
172 MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14); | |
173 MD5STEP(F2, b, c, d, a, in[ 4] + 0xe7d3fbc8, 20); | |
174 MD5STEP(F2, a, b, c, d, in[ 9] + 0x21e1cde6, 5); | |
175 MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9); | |
176 MD5STEP(F2, c, d, a, b, in[ 3] + 0xf4d50d87, 14); | |
177 MD5STEP(F2, b, c, d, a, in[ 8] + 0x455a14ed, 20); | |
178 MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5); | |
179 MD5STEP(F2, d, a, b, c, in[ 2] + 0xfcefa3f8, 9); | |
180 MD5STEP(F2, c, d, a, b, in[ 7] + 0x676f02d9, 14); | |
181 MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20); | |
182 | |
183 MD5STEP(F3, a, b, c, d, in[ 5] + 0xfffa3942, 4); | |
184 MD5STEP(F3, d, a, b, c, in[ 8] + 0x8771f681, 11); | |
185 MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16); | |
186 MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23); | |
187 MD5STEP(F3, a, b, c, d, in[ 1] + 0xa4beea44, 4); | |
188 MD5STEP(F3, d, a, b, c, in[ 4] + 0x4bdecfa9, 11); | |
189 MD5STEP(F3, c, d, a, b, in[ 7] + 0xf6bb4b60, 16); | |
190 MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23); | |
191 MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4); | |
192 MD5STEP(F3, d, a, b, c, in[ 0] + 0xeaa127fa, 11); | |
193 MD5STEP(F3, c, d, a, b, in[ 3] + 0xd4ef3085, 16); | |
194 MD5STEP(F3, b, c, d, a, in[ 6] + 0x04881d05, 23); | |
195 MD5STEP(F3, a, b, c, d, in[ 9] + 0xd9d4d039, 4); | |
196 MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11); | |
197 MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16); | |
198 MD5STEP(F3, b, c, d, a, in[ 2] + 0xc4ac5665, 23); | |
199 | |
200 MD5STEP(F4, a, b, c, d, in[ 0] + 0xf4292244, 6); | |
201 MD5STEP(F4, d, a, b, c, in[ 7] + 0x432aff97, 10); | |
202 MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15); | |
203 MD5STEP(F4, b, c, d, a, in[ 5] + 0xfc93a039, 21); | |
204 MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6); | |
205 MD5STEP(F4, d, a, b, c, in[ 3] + 0x8f0ccc92, 10); | |
206 MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15); | |
207 MD5STEP(F4, b, c, d, a, in[ 1] + 0x85845dd1, 21); | |
208 MD5STEP(F4, a, b, c, d, in[ 8] + 0x6fa87e4f, 6); | |
209 MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10); | |
210 MD5STEP(F4, c, d, a, b, in[ 6] + 0xa3014314, 15); | |
211 MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21); | |
212 MD5STEP(F4, a, b, c, d, in[ 4] + 0xf7537e82, 6); | |
213 MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10); | |
214 MD5STEP(F4, c, d, a, b, in[ 2] + 0x2ad7d2bb, 15); | |
215 MD5STEP(F4, b, c, d, a, in[ 9] + 0xeb86d391, 21); | |
216 buf[0] += a; | |
217 buf[1] += b; | |
218 buf[2] += c; | |
219 buf[3] += d; | |
220 } | |
221 | |
222 } // namespace rtc | |
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