Document SHA-1 functions and structures
[libav.git] / libavutil / sha1.c
1 /*
2 * Copyright (C) 2007 Michael Niedermayer <michaelni@gmx.at>
3 * based on public domain SHA-1 code by Steve Reid <steve@edmweb.com>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #include "common.h"
23 #include "bswap.h"
24 #include "sha1.h"
25
26 /** hash context */
27 typedef struct AVSHA1 {
28 uint64_t count; ///< number of bytes in buffer
29 uint8_t buffer[64]; ///< 512-bit buffer of input values used in hash updating
30 uint32_t state[5]; ///< current hash value
31 } AVSHA1;
32
33 const int av_sha1_size = sizeof(AVSHA1);
34
35 #define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))
36
37 /* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
38 #define blk0(i) (block[i] = be2me_32(((const uint32_t*)buffer)[i]))
39 #define blk(i) (block[i] = rol(block[i-3] ^ block[i-8] ^ block[i-14] ^ block[i-16], 1))
40
41 #define R0(v,w,x,y,z,i) z += ((w&(x^y))^y) + blk0(i) + 0x5A827999 + rol(v, 5); w = rol(w, 30);
42 #define R1(v,w,x,y,z,i) z += ((w&(x^y))^y) + blk (i) + 0x5A827999 + rol(v, 5); w = rol(w, 30);
43 #define R2(v,w,x,y,z,i) z += ( w^x ^y) + blk (i) + 0x6ED9EBA1 + rol(v, 5); w = rol(w, 30);
44 #define R3(v,w,x,y,z,i) z += (((w|x)&y)|(w&x)) + blk (i) + 0x8F1BBCDC + rol(v, 5); w = rol(w, 30);
45 #define R4(v,w,x,y,z,i) z += ( w^x ^y) + blk (i) + 0xCA62C1D6 + rol(v, 5); w = rol(w, 30);
46
47 /* Hash a single 512-bit block. This is the core of the algorithm. */
48
49 static void transform(uint32_t state[5], const uint8_t buffer[64])
50 {
51 uint32_t block[80];
52 unsigned int i, a, b, c, d, e;
53
54 a = state[0];
55 b = state[1];
56 c = state[2];
57 d = state[3];
58 e = state[4];
59 #if CONFIG_SMALL
60 for (i = 0; i < 80; i++) {
61 int t;
62 if (i < 16)
63 t = be2me_32(((uint32_t*)buffer)[i]);
64 else
65 t = rol(block[i-3] ^ block[i-8] ^ block[i-14] ^ block[i-16], 1);
66 block[i] = t;
67 t += e + rol(a, 5);
68 if (i < 40) {
69 if (i < 20)
70 t += ((b&(c^d))^d) + 0x5A827999;
71 else
72 t += ( b^c ^d) + 0x6ED9EBA1;
73 } else {
74 if (i < 60)
75 t += (((b|c)&d)|(b&c)) + 0x8F1BBCDC;
76 else
77 t += ( b^c ^d) + 0xCA62C1D6;
78 }
79 e = d;
80 d = c;
81 c = rol(b, 30);
82 b = a;
83 a = t;
84 }
85 #else
86 for (i = 0; i < 15; i += 5) {
87 R0(a, b, c, d, e, 0 + i);
88 R0(e, a, b, c, d, 1 + i);
89 R0(d, e, a, b, c, 2 + i);
90 R0(c, d, e, a, b, 3 + i);
91 R0(b, c, d, e, a, 4 + i);
92 }
93 R0(a, b, c, d, e, 15);
94 R1(e, a, b, c, d, 16);
95 R1(d, e, a, b, c, 17);
96 R1(c, d, e, a, b, 18);
97 R1(b, c, d, e, a, 19);
98 for (i = 20; i < 40; i += 5) {
99 R2(a, b, c, d, e, 0 + i);
100 R2(e, a, b, c, d, 1 + i);
101 R2(d, e, a, b, c, 2 + i);
102 R2(c, d, e, a, b, 3 + i);
103 R2(b, c, d, e, a, 4 + i);
104 }
105 for (; i < 60; i += 5) {
106 R3(a, b, c, d, e, 0 + i);
107 R3(e, a, b, c, d, 1 + i);
108 R3(d, e, a, b, c, 2 + i);
109 R3(c, d, e, a, b, 3 + i);
110 R3(b, c, d, e, a, 4 + i);
111 }
112 for (; i < 80; i += 5) {
113 R4(a, b, c, d, e, 0 + i);
114 R4(e, a, b, c, d, 1 + i);
115 R4(d, e, a, b, c, 2 + i);
116 R4(c, d, e, a, b, 3 + i);
117 R4(b, c, d, e, a, 4 + i);
118 }
119 #endif
120 state[0] += a;
121 state[1] += b;
122 state[2] += c;
123 state[3] += d;
124 state[4] += e;
125 }
126
127 void av_sha1_init(AVSHA1* ctx)
128 {
129 ctx->state[0] = 0x67452301;
130 ctx->state[1] = 0xEFCDAB89;
131 ctx->state[2] = 0x98BADCFE;
132 ctx->state[3] = 0x10325476;
133 ctx->state[4] = 0xC3D2E1F0;
134 ctx->count = 0;
135 }
136
137 void av_sha1_update(AVSHA1* ctx, const uint8_t* data, unsigned int len)
138 {
139 unsigned int i, j;
140
141 j = ctx->count & 63;
142 ctx->count += len;
143 #if CONFIG_SMALL
144 for (i = 0; i < len; i++) {
145 ctx->buffer[j++] = data[i];
146 if (64 == j) {
147 transform(ctx->state, ctx->buffer);
148 j = 0;
149 }
150 }
151 #else
152 if ((j + len) > 63) {
153 memcpy(&ctx->buffer[j], data, (i = 64 - j));
154 transform(ctx->state, ctx->buffer);
155 for (; i + 63 < len; i += 64)
156 transform(ctx->state, &data[i]);
157 j = 0;
158 } else
159 i = 0;
160 memcpy(&ctx->buffer[j], &data[i], len - i);
161 #endif
162 }
163
164 void av_sha1_final(AVSHA1* ctx, uint8_t digest[20])
165 {
166 int i;
167 uint64_t finalcount = be2me_64(ctx->count << 3);
168
169 av_sha1_update(ctx, "\200", 1);
170 while ((ctx->count & 63) != 56)
171 av_sha1_update(ctx, "", 1);
172 av_sha1_update(ctx, (uint8_t *)&finalcount, 8); /* Should cause a transform() */
173 for (i = 0; i < 5; i++)
174 ((uint32_t*)digest)[i] = be2me_32(ctx->state[i]);
175 }
176
177 #ifdef TEST
178 #include <stdio.h>
179 #undef printf
180
181 int main(void)
182 {
183 int i, k;
184 AVSHA1 ctx;
185 unsigned char digest[20];
186
187 for (k = 0; k < 3; k++) {
188 av_sha1_init(&ctx);
189 if (k == 0)
190 av_sha1_update(&ctx, "abc", 3);
191 else if (k == 1)
192 av_sha1_update(&ctx, "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq", 56);
193 else
194 for (i = 0; i < 1000 * 1000; i++)
195 av_sha1_update(&ctx, "a", 1);
196 av_sha1_final(&ctx, digest);
197 for (i = 0; i < 20; i++)
198 printf("%02X", digest[i]);
199 putchar('\n');
200 }
201 //test vectors (from FIPS PUB 180-1)
202 printf("A9993E36 4706816A BA3E2571 7850C26C 9CD0D89D\n"
203 "84983E44 1C3BD26E BAAE4AA1 F95129E5 E54670F1\n"
204 "34AA973C D4C4DAA4 F61EEB2B DBAD2731 6534016F\n");
205
206 return 0;
207 }
208 #endif