9 * \brief SHA-256 implementation.
15 #include <string.h> /* for memcpy, memmove, memset */
20 #if defined LITTLE_ENDIAN
21 #elif defined BIG_ENDIAN
23 #error specify endianess!!!
27 /*************************************************************************/
29 uint32_t sha256_init_vector[]={
30 0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A,
31 0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19 };
34 /*************************************************************************/
37 * \brief \c sh256_init initialises a sha256 context for hashing.
38 * \c sh256_init c initialises the given sha256 context for hashing
39 * @param state pointer to a sha256 context
42 void sha256_init(sha256_ctx_t *state){
44 memcpy(state->h, sha256_init_vector, 8*4);
47 /*************************************************************************/
50 * rotate x right by n positions
52 uint32_t rotr32( uint32_t x, uint8_t n){
53 return ((x>>n) | (x<<(32-n)));
57 /*************************************************************************/
59 // #define CHANGE_ENDIAN32(x) (((x)<<24) | ((x)>>24) | (((x)& 0x0000ff00)<<8) | (((x)& 0x00ff0000)>>8))
61 uint32_t change_endian32(uint32_t x){
62 return (((x)<<24) | ((x)>>24) | (((x)& 0x0000ff00)<<8) | (((x)& 0x00ff0000)>>8));
66 /*************************************************************************/
68 /* sha256 functions as macros for speed and size, cause they are called only once */
70 #define CH(x,y,z) (((x)&(y)) ^ ((~(x))&(z)))
71 #define MAJ(x,y,z) (((x)&(y)) ^ ((x)&(z)) ^ ((y)&(z)))
73 #define SIGMA0(x) (rotr32((x),2) ^ rotr32((x),13) ^ rotr32((x),22))
74 #define SIGMA1(x) (rotr32((x),6) ^ rotr32((x),11) ^ rotr32((x),25))
75 #define SIGMA_a(x) (rotr32((x),7) ^ rotr32((x),18) ^ ((x)>>3))
76 #define SIGMA_b(x) (rotr32((x),17) ^ rotr32((x),19) ^ ((x)>>10))
80 0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
81 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
82 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
83 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
84 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
85 0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
86 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
87 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
91 /*************************************************************************/
94 * block must be, 512, Bit = 64, Byte, long !!!
96 void sha256_nextBlock (sha256_ctx_t *state, void* block){
97 uint32_t w[64]; /* this is 256, byte, large, */
102 #if defined LITTLE_ENDIAN
103 for (i=0; i<16; ++i){
104 w[i]= change_endian32(((uint32_t*)block)[i]);
106 #elif defined BIG_ENDIAN
107 memcpy((void*)w, block, 64);
109 for (i=16; i<64; ++i){
110 w[i] = SIGMA_b(w[i-2]) + w[i-7] + SIGMA_a(w[i-15]) + w[i-16];
113 /* init working variables */
114 memcpy((void*)a,(void*)(state->h), 8*4);
116 /* do the, fun stuff, */
117 for (i=0; i<64; ++i){
118 t1 = a[7] + SIGMA1(a[4]) + CH(a[4],a[5],a[6]) + k[i] + w[i];
119 t2 = SIGMA0(a[0]) + MAJ(a[0],a[1],a[2]);
120 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]; */
125 /* update, the, state, */
129 state->length += 512;
133 /*************************************************************************/
136 * \brief function to process the last block being hashed
137 * @param state Pointer to the context in which this block should be processed.
138 * @param block Pointer to the message wich should be hashed.
139 * @param length is the length of only THIS block in BITS not in bytes!
140 * bits are big endian, meaning high bits come first.
141 * if you have a message with bits at the end, the byte must be padded with zeros
143 void sha256_lastBlock(sha256_ctx_t *state, void* block, uint16_t length){
144 uint8_t lb[SHA256_BLOCK_BITS/8]; /* local block */
145 state->length += length;
146 memcpy (&(lb[0]), block, length/8);
148 /* set the final one bit */
149 if (length & 0x3){ // if we have single bits at the end
150 lb[length/8] = ((uint8_t*)(block))[length/8];
154 lb[length/8] |= 0x80>>(length & 0x3);
155 length =(length >> 3) + 1; /* from now on length contains the number of BYTES in lb*/
157 if (length>64-8){ /* not enouth space for 64bit length value */
158 memset((void*)(&(lb[length])), 0, 64-length);
159 sha256_nextBlock(state, lb);
160 state->length -= 512;
163 memset((void*)(&(lb[length])), 0, 56-length);
164 /* store the 64bit length value */
165 #if defined LITTLE_ENDIAN
166 /* this is now rolled up */
168 for (i=1; i<=8; ++i){
169 lb[55+i] = (uint8_t)(state->length>>(64- 8*i));
171 #elif defined BIG_ENDIAN
172 *((uint64_t)&(lb[56])) = state->length;
174 sha256_nextBlock(state, lb);
178 /*************************************************************************/
183 void sha256(sha256_hash_t *dest, void* msg, uint32_t length){ /* length could be choosen longer but this is for µC */
186 while(length >= SHA256_BLOCK_BITS){
187 sha256_nextBlock(&s, msg);
188 msg += SHA256_BLOCK_BITS/8;
189 length -= SHA256_BLOCK_BITS;
191 sha256_lastBlock(&s, msg, length);
192 sha256_ctx2hash(dest,&s);
197 /*************************************************************************/
199 void sha256_ctx2hash(sha256_hash_t *dest, sha256_ctx_t *state){
200 #if defined LITTLE_ENDIAN
203 ((uint32_t*)dest)[i] = change_endian32(state->h[i]);
206 if (dest != state->h)
207 memcpy(dest, state->h, SHA256_HASH_BITS/8);
209 # error unsupported endian type!