sha1/sha1.c

   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 (void *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 (void *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