3 This file is part of the AVR-Crypto-Lib.
4 Copyright (C) 2008 Daniel Otte (daniel.otte@rub.de)
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.
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.
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/>.
27 * \brief SHA-256 implementation.
33 #include <string.h> /* for memcpy, memmove, memset */
38 #if defined LITTLE_ENDIAN
39 #elif defined BIG_ENDIAN
41 #error specify endianess!!!
45 /*************************************************************************/
47 uint32_t sha256_init_vector[]={
48 0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A,
49 0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19 };
52 /*************************************************************************/
55 * \brief \c sh256_init initialises a sha256 context for hashing.
56 * \c sh256_init c initialises the given sha256 context for hashing
57 * @param state pointer to a sha256 context
60 void sha256_init(sha256_ctx_t *state){
62 memcpy(state->h, sha256_init_vector, 8*4);
65 /*************************************************************************/
68 * rotate x right by n positions
70 uint32_t rotr32( uint32_t x, uint8_t n){
71 return ((x>>n) | (x<<(32-n)));
75 /*************************************************************************/
77 // #define CHANGE_ENDIAN32(x) (((x)<<24) | ((x)>>24) | (((x)& 0x0000ff00)<<8) | (((x)& 0x00ff0000)>>8))
79 uint32_t change_endian32(uint32_t x){
80 return (((x)<<24) | ((x)>>24) | (((x)& 0x0000ff00)<<8) | (((x)& 0x00ff0000)>>8));
84 /*************************************************************************/
86 /* sha256 functions as macros for speed and size, cause they are called only once */
88 #define CH(x,y,z) (((x)&(y)) ^ ((~(x))&(z)))
89 #define MAJ(x,y,z) (((x)&(y)) ^ ((x)&(z)) ^ ((y)&(z)))
91 #define SIGMA0(x) (rotr32((x),2) ^ rotr32((x),13) ^ rotr32((x),22))
92 #define SIGMA1(x) (rotr32((x),6) ^ rotr32((x),11) ^ rotr32((x),25))
93 #define SIGMA_a(x) (rotr32((x),7) ^ rotr32((x),18) ^ ((x)>>3))
94 #define SIGMA_b(x) (rotr32((x),17) ^ rotr32((x),19) ^ ((x)>>10))
98 0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
99 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
100 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
101 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
102 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
103 0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
104 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
105 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
109 /*************************************************************************/
112 * block must be, 512, Bit = 64, Byte, long !!!
114 void sha256_nextBlock (sha256_ctx_t *state, const void* block){
115 uint32_t w[64]; /* this is 256, byte, large, */
120 #if defined LITTLE_ENDIAN
121 for (i=0; i<16; ++i){
122 w[i]= change_endian32(((uint32_t*)block)[i]);
124 #elif defined BIG_ENDIAN
125 memcpy((void*)w, block, 64);
127 for (i=16; i<64; ++i){
128 w[i] = SIGMA_b(w[i-2]) + w[i-7] + SIGMA_a(w[i-15]) + w[i-16];
131 /* init working variables */
132 memcpy((void*)a,(void*)(state->h), 8*4);
134 /* do the, fun stuff, */
135 for (i=0; i<64; ++i){
136 t1 = a[7] + SIGMA1(a[4]) + CH(a[4],a[5],a[6]) + k[i] + w[i];
137 t2 = SIGMA0(a[0]) + MAJ(a[0],a[1],a[2]);
138 memmove(&(a[1]), &(a[0]), 7*4); /* a[7]=a[6]; a[6]=a[5]; a[5]=a[4]; a[4]=a[3]; a[3]=a[2]; a[2]=a[1]; a[1]=a[0]; */
143 /* update, the, state, */
147 state->length += 512;
151 /*************************************************************************/
154 * \brief function to process the last block being hashed
155 * @param state Pointer to the context in which this block should be processed.
156 * @param block Pointer to the message wich should be hashed.
157 * @param length is the length of only THIS block in BITS not in bytes!
158 * bits are big endian, meaning high bits come first.
159 * if you have a message with bits at the end, the byte must be padded with zeros
161 void sha256_lastBlock(sha256_ctx_t *state, const void* block, uint16_t length){
162 uint8_t lb[SHA256_BLOCK_BITS/8]; /* local block */
163 state->length += length;
164 memcpy (&(lb[0]), block, length/8);
166 /* set the final one bit */
167 if (length & 0x7){ // if we have single bits at the end
168 lb[length/8] = ((uint8_t*)(block))[length/8];
172 lb[length/8] |= 0x80>>(length & 0x7);
173 length =(length >> 3) + 1; /* from now on length contains the number of BYTES in lb*/
175 if (length>64-8){ /* not enouth space for 64bit length value */
176 memset((void*)(&(lb[length])), 0, 64-length);
177 sha256_nextBlock(state, lb);
178 state->length -= 512;
181 memset((void*)(&(lb[length])), 0, 56-length);
182 /* store the 64bit length value */
183 #if defined LITTLE_ENDIAN
184 /* this is now rolled up */
186 for (i=1; i<=8; ++i){
187 lb[55+i] = (uint8_t)(state->length>>(64- 8*i));
189 #elif defined BIG_ENDIAN
190 *((uint64_t)&(lb[56])) = state->length;
192 sha256_nextBlock(state, lb);
196 /*************************************************************************/
201 void sha256(sha256_hash_t *dest, const void* msg, uint32_t length){ /* length could be choosen longer but this is for µC */
204 while(length >= SHA256_BLOCK_BITS){
205 sha256_nextBlock(&s, msg);
206 msg = (uint8_t*)msg + SHA256_BLOCK_BITS/8;
207 length -= SHA256_BLOCK_BITS;
209 sha256_lastBlock(&s, msg, length);
210 sha256_ctx2hash(dest,&s);
215 /*************************************************************************/
217 void sha256_ctx2hash(sha256_hash_t *dest, const sha256_ctx_t *state){
218 #if defined LITTLE_ENDIAN
221 ((uint32_t*)dest)[i] = change_endian32(state->h[i]);
224 if (dest != state->h)
225 memcpy(dest, state->h, SHA256_HASH_BITS/8);
227 # error unsupported endian type!