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1 /* sha1.c */
2 /*
3     This file is part of the AVR-Crypto-Lib.
4     Copyright (C) 2008, 2009  Daniel Otte (daniel.otte@rub.de)
5
6     This program is free software: you can redistribute it and/or modify
7     it under the terms of the GNU General Public License as published by
8     the Free Software Foundation, either version 3 of the License, or
9     (at your option) any later version.
10
11     This program is distributed in the hope that it will be useful,
12     but WITHOUT ANY WARRANTY; without even the implied warranty of
13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14     GNU General Public License for more details.
15
16     You should have received a copy of the GNU General Public License
17     along with this program.  If not, see <http://www.gnu.org/licenses/>.
18 */
19 /**
20  * \file        sha1.c
21  * \author      Daniel Otte
22  * \date        2006-10-08
23  * \license GPLv3 or later
24  * \brief SHA-1 implementation.
25  *
26  */
27
28 #include <string.h> /* memcpy & co */
29 #include <stdint.h>
30 #include "config.h"
31 #include "debug.h"
32 #include "sha1.h"
33
34 #ifdef DEBUG
35 #  undef DEBUG
36 #endif
37
38 #include "cli.h"
39
40 #define LITTLE_ENDIAN
41
42 /********************************************************************************************************/
43
44 /**
45  * \brief initialises given SHA-1 context
46  *
47  */
48 void sha1_init(sha1_ctx_t *state){
49         DEBUG_S("\r\nSHA1_INIT");
50         state->h[0] = 0x67452301;
51         state->h[1] = 0xefcdab89;
52         state->h[2] = 0x98badcfe;
53         state->h[3] = 0x10325476;
54         state->h[4] = 0xc3d2e1f0;
55         state->length = 0;
56 }
57
58 /********************************************************************************************************/
59 /* some helping functions */
60 uint32_t rotl32(uint32_t n, uint8_t bits){
61         return ((n<<bits) | (n>>(32-bits)));
62 }
63
64 uint32_t change_endian32(uint32_t x){
65         return (((x)<<24) | ((x)>>24) | (((x)& 0x0000ff00)<<8) | (((x)& 0x00ff0000)>>8));
66 }
67
68
69 /* three SHA-1 inner functions */
70 uint32_t ch(uint32_t x, uint32_t y, uint32_t z){
71         DEBUG_S("\r\nCH");
72         return ((x&y)^((~x)&z));
73 }
74
75 uint32_t maj(uint32_t x, uint32_t y, uint32_t z){
76         DEBUG_S("\r\nMAJ");
77         return ((x&y)^(x&z)^(y&z));
78 }
79
80 uint32_t parity(uint32_t x, uint32_t y, uint32_t z){
81         DEBUG_S("\r\nPARITY");
82         return ((x^y)^z);
83 }
84
85 /********************************************************************************************************/
86 /**
87  * \brief "add" a block to the hash
88  * This is the core function of the hash algorithm. To understand how it's working
89  * and what thoese variables do, take a look at FIPS-182. This is an "alternativ" implementation
90  */
91
92 #define MASK 0x0000000f
93
94 typedef uint32_t (*pf_t)(uint32_t x, uint32_t y, uint32_t z);
95
96 void sha1_nextBlock (sha1_ctx_t *state, const void* block){
97         uint32_t a[5];
98         uint32_t w[16];
99         uint32_t temp;
100         uint8_t t,s,fi, fib;
101         pf_t f[] = {ch,parity,maj,parity};
102         uint32_t k[4]={ 0x5a827999,
103                                         0x6ed9eba1,
104                                         0x8f1bbcdc,
105                                         0xca62c1d6};
106
107         /* load the w array (changing the endian and so) */
108         for(t=0; t<16; ++t){
109                 w[t] = change_endian32(((uint32_t*)block)[t]);
110         }
111
112 #if DEBUG
113         uint8_t dbgi;
114         for(dbgi=0; dbgi<16; ++dbgi){
115                 /*
116                 DEBUG_S("\n\rBlock:");
117                 DEBUG_B(dbgi);
118                 DEBUG_C(':');
119                 */
120                 cli_putstr_P(PSTR("\r\nBlock:"));
121                 cli_hexdump(&dbgi, 1);
122                 cli_putc(':');
123                 cli_hexdump(&(w[dbgi]) ,4);
124         }
125 #endif
126
127         /* load the state */
128         memcpy(a, state->h, 5*sizeof(uint32_t));
129
130
131         /* the fun stuff */
132         for(fi=0,fib=0,t=0; t<=79; ++t){
133                 s = t & MASK;
134                 if(t>=16){
135                         #if DEBUG
136                          DEBUG_S("\r\n ws = "); cli_hexdump(&(w[s]), 4);
137                         #endif
138                         w[s] = rotl32( w[(s+13)&MASK] ^ w[(s+8)&MASK] ^
139                                  w[(s+ 2)&MASK] ^ w[s] ,1);
140                         #ifdef DEBUG
141                          DEBUG_S(" --> ws = "); cli_hexdump(&(w[s]), 4);
142                         #endif
143                 }
144
145                 uint32_t dtemp;
146                 temp = rotl32(a[0],5) + (dtemp=f[fi](a[1],a[2],a[3])) + a[4] + k[fi] + w[s];
147                 memmove(&(a[1]), &(a[0]), 4*sizeof(uint32_t)); /* e=d; d=c; c=b; b=a; */
148                 a[0] = temp;
149                 a[2] = rotl32(a[2],30); /* we might also do rotr32(c,2) */
150                 fib++;
151                 if(fib==20){
152                         fib=0;
153                         fi = (fi+1)%4;
154                 }
155                 #if DEBUG
156                 /* debug dump */
157                 DEBUG_S("\r\nt = "); DEBUG_B(t);
158                 DEBUG_S("; a[]: ");
159                  cli_hexdump(a, 5*4);
160                 DEBUG_S("; k = ");
161                  cli_hexdump(&(k[t/20]), 4);
162                 DEBUG_S("; f(b,c,d) = ");
163                  cli_hexdump(&dtemp, 4);
164                 #endif
165         }
166
167         /* update the state */
168         for(t=0; t<5; ++t){
169                 state->h[t] += a[t];
170         }
171         state->length += 512;
172 }
173
174 /********************************************************************************************************/
175
176 void sha1_lastBlock(sha1_ctx_t *state, const void* block, uint16_t length){
177         uint8_t lb[SHA1_BLOCK_BYTES]; /* local block */
178         while(length>=SHA1_BLOCK_BITS){
179                 sha1_nextBlock(state, block);
180                 length -= SHA1_BLOCK_BITS;
181                 block = (uint8_t*)block + SHA1_BLOCK_BYTES;
182         }
183         state->length += length;
184         memset(lb, 0, SHA1_BLOCK_BYTES);
185         memcpy (lb, block, (length+7)>>3);
186
187         /* set the final one bit */
188         lb[length>>3] |= 0x80>>(length & 0x07);
189
190         if (length>512-64-1){ /* not enouth space for 64bit length value */
191                 sha1_nextBlock(state, lb);
192                 state->length -= 512;
193                 memset(lb, 0, SHA1_BLOCK_BYTES);
194         }
195         /* store the 64bit length value */
196 #if defined LITTLE_ENDIAN
197                 /* this is now rolled up */
198         uint8_t i;
199         for (i=0; i<8; ++i){
200                 lb[56+i] = ((uint8_t*)&(state->length))[7-i];
201         }
202 #elif defined BIG_ENDIAN
203         *((uint64_t)&(lb[56])) = state->length;
204 #endif
205         sha1_nextBlock(state, lb);
206 }
207
208 /********************************************************************************************************/
209
210 void sha1_ctx2hash (sha1_hash_t *dest, sha1_ctx_t *state){
211 #if defined LITTLE_ENDIAN
212         uint8_t i;
213         for(i=0; i<5; ++i){
214                 ((uint32_t*)dest)[i] = change_endian32(state->h[i]);
215         }
216 #elif BIG_ENDIAN
217         if (dest != state->h)
218                 memcpy(dest, state->h, SHA1_HASH_BITS/8);
219 #else
220 # error unsupported endian type!
221 #endif
222 }
223
224 /********************************************************************************************************/
225 /**
226  *
227  *
228  */
229 void sha1 (sha1_hash_t *dest, const void* msg, uint32_t length){
230         sha1_ctx_t s;
231         DEBUG_S("\r\nBLA BLUB");
232         sha1_init(&s);
233         while(length & (~0x0001ff)){ /* length>=512 */
234                 DEBUG_S("\r\none block");
235                 sha1_nextBlock(&s, msg);
236                 msg = (uint8_t*)msg + SHA1_BLOCK_BITS/8; /* increment pointer to next block */
237                 length -= SHA1_BLOCK_BITS;
238         }
239         sha1_lastBlock(&s, msg, length);
240         sha1_ctx2hash(dest, &s);
241 }
242
243