sha1.c

   1 /**
   2  * \file        sha1.c
   3  * \author      Daniel Otte
   4  * \date        08.10.2006
   5  * \par License:
   6  * GPLv3
   7  * \brief SHA-1 implementation.
   8  *
   9  */
  10
  11 #include <string.h> /* memcpy & co */
  12 #include <stdint.h>
  13 #include "config.h"
  14 #undef DEBUG
  15 #include "debug.h"
  16 #include "sha1.h"
  17
  18 #define LITTLE_ENDIAN
  19
  20 /********************************************************************************************************/
  21
  22 /**
  23  * \brief initialises given SHA-1 context
  24  *
  25  */
  26 void sha1_init(sha1_ctx_t *state){
  27         DEBUG_S("\r\nSHA1_INIT");
  28         state->h[0] = 0x67452301;
  29         state->h[1] = 0xefcdab89;
  30         state->h[2] = 0x98badcfe;
  31         state->h[3] = 0x10325476;
  32         state->h[4] = 0xc3d2e1f0;
  33         state->length = 0;
  34 }
  35
  36 /********************************************************************************************************/
  37 /* some helping functions */
  38 uint32_t rotl32(uint32_t n, uint8_t bits){
  39         return ((n<<bits) | (n>>(32-bits)));
  40 }
  41
  42 uint32_t change_endian32(uint32_t x){
  43         return (((x)<<24) | ((x)>>24) | (((x)& 0x0000ff00)<<8) | (((x)& 0x00ff0000)>>8));
  44 }
  45
  46
  47 /* three SHA-1 inner functions */
  48 uint32_t ch(uint32_t x, uint32_t y, uint32_t z){
  49         DEBUG_S("\r\nCH");
  50         return ((x&y)^((~x)&z));
  51 }
  52
  53 uint32_t maj(uint32_t x, uint32_t y, uint32_t z){
  54         DEBUG_S("\r\nMAJ");
  55         return ((x&y)^(x&z)^(y&z));
  56 }
  57
  58 uint32_t parity(uint32_t x, uint32_t y, uint32_t z){
  59         DEBUG_S("\r\nPARITY");
  60         return ((x^y)^z);
  61 }
  62
  63 /********************************************************************************************************/
  64 /**
  65  * \brief "add" a block to the hash
  66  * This is the core function of the hash algorithm. To understand how it's working
  67  * and what thoese variables do, take a look at FIPS-182. This is an "alternativ" implementation
  68  */
  69
  70 #define MASK 0x0000000f
  71
  72 typedef uint32_t (*pf_t)(uint32_t x, uint32_t y, uint32_t z);
  73
  74 void sha1_nextBlock (sha1_ctx_t *state, void* block){
  75         uint32_t a[5];
  76         uint32_t w[16];
  77         uint32_t temp;
  78         uint8_t t,s;
  79         pf_t f[] = {ch,parity,maj,parity};
  80         uint32_t k[4]={ 0x5a827999,
  81                                         0x6ed9eba1,
  82                                         0x8f1bbcdc,
  83                                         0xca62c1d6};
  84
  85         /* load the w array (changing the endian and so) */
  86         for(t=0; t<16; ++t){
  87                 w[t] = change_endian32(((uint32_t*)block)[t]);
  88         }
  89
  90         uint8_t dbgi;
  91         for(dbgi=0; dbgi<16; ++dbgi){
  92                 DEBUG_S("\n\rBlock:");
  93                 DEBUG_B(dbgi);
  94                 DEBUG_C(':');
  95                 #ifdef DEBUG
  96                         uart_hexdump(&(w[dbgi]) ,4);
  97                 #endif
  98         }
  99
 100
 101         /* load the state */
 102         memcpy(a, state->h, 5*sizeof(uint32_t));
 103
 104
 105         /* the fun stuff */
 106         for(t=0; t<=79; ++t){
 107                 s = t & MASK;
 108                 if(t>=16){
 109                         #ifdef DEBUG
 110                          DEBUG_S("\r\n ws = "); uart_hexdump(&ws, 4);
 111                         #endif
 112                         w[s] = rotl32( w[(s+13)&MASK] ^ w[(s+8)&MASK] ^
 113                                  w[(s+ 2)&MASK] ^ w[s] ,1);
 114                         #ifdef DEBUG
 115                          DEBUG_S(" --> ws = "); uart_hexdump(&(w[s]), 4);
 116                         #endif
 117                 }
 118
 119                 uint32_t dtemp;
 120                 temp = rotl32(a[0],5) + (dtemp=f[t/20](a[1],a[2],a[3])) + a[4] + k[t/20] + w[s];
 121                 memmove(&(a[1]), &(a[0]), 4*sizeof(uint32_t)); /* e=d; d=c; c=b; b=a; */
 122                 a[0] = temp;
 123                 a[2] = rotl32(a[2],30); /* we might also do rotr32(c,2) */
 124
 125                 /* debug dump */
 126                 DEBUG_S("\r\nt = "); DEBUG_B(t);
 127                 DEBUG_S("; a[]: ");
 128                 #ifdef DEBUG
 129                  uart_hexdump(a, 5*4);
 130                 #endif
 131                 DEBUG_S("; k = ");
 132                 #ifdef DEBUG
 133                  uart_hexdump(&(k[t/20]), 4);
 134                 #endif
 135                 DEBUG_S("; f(b,c,d) = ");
 136                 #ifdef DEBUG
 137                  uart_hexdump(&dtemp, 4);
 138                 #endif
 139         }
 140
 141         /* update the state */
 142         for(t=0; t<5; ++t){
 143                 state->h[t] += a[t];
 144         }
 145         state->length += 512;
 146 }
 147
 148 /********************************************************************************************************/
 149
 150 void sha1_lastBlock(sha1_ctx_t *state, void* block, uint16_t length){
 151         uint8_t lb[SHA1_BLOCK_BITS/8]; /* local block */
 152         state->length += length;
 153         memcpy (&(lb[0]), block, length/8);
 154
 155         /* set the final one bit */
 156         if (length & 0x3){ /* if we have single bits at the end */
 157                 lb[length/8] = ((uint8_t*)(block))[length/8];
 158         } else {
 159                 lb[length/8] = 0;
 160         }
 161         lb[length/8] |= 0x80>>(length & 0x3);
 162         length =(length >> 3) + 1; /* from now on length contains the number of BYTES in lb*/
 163         /* pad with zeros */
 164         if (length>64-8){ /* not enouth space for 64bit length value */
 165                 memset((void*)(&(lb[length])), 0, 64-length);
 166                 sha1_nextBlock(state, lb);
 167                 state->length -= 512;
 168                 length = 0;
 169         }
 170         memset((void*)(&(lb[length])), 0, 56-length);
 171         /* store the 64bit length value */
 172 #if defined LITTLE_ENDIAN
 173                 /* this is now rolled up */
 174         uint8_t i;
 175         for (i=1; i<=8; ++i){
 176                 lb[55+i] = (uint8_t)(state->length>>(64- 8*i));
 177         }
 178 #elif defined BIG_ENDIAN
 179         *((uint64_t)&(lb[56])) = state->length;
 180 #endif
 181         sha1_nextBlock(state, lb);
 182 }
 183
 184 /********************************************************************************************************/
 185
 186 void sha1_ctx2hash (sha1_hash_t *dest, sha1_ctx_t *state){
 187 #if defined LITTLE_ENDIAN
 188         uint8_t i;
 189         for(i=0; i<8; ++i){
 190                 ((uint32_t*)dest)[i] = change_endian32(state->h[i]);
 191         }
 192 #elif BIG_ENDIAN
 193         if (dest != state->h)
 194                 memcpy(dest, state->h, SHA256_HASH_BITS/8);
 195 #else
 196 # error unsupported endian type!
 197 #endif
 198 }
 199
 200 /********************************************************************************************************/
 201 /**
 202  *
 203  *
 204  */
 205 void sha1 (sha1_hash_t *dest, void* msg, uint32_t length){
 206         sha1_ctx_t s;
 207         DEBUG_S("\r\nBLA BLUB");
 208         sha1_init(&s);
 209         while(length & (~0x0001ff)){ /* length>=512 */
 210                 DEBUG_S("\r\none block");
 211                 sha1_nextBlock(&s, msg);
 212                 msg += SHA1_BLOCK_BITS/8; /* increment pointer to next block */
 213                 length -= SHA1_BLOCK_BITS;
 214         }
 215         sha1_lastBlock(&s, msg, length);
 216         sha1_ctx2hash(dest, &s);
 217 }
 218
 219