/* sha256.c */
/*
This file is part of the ARM-Crypto-Lib.
Copyright (C) 2006-2010 Daniel Otte (daniel.otte@rub.de)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see .
*/
/**
* \file sha256.c
* \author Daniel Otte
* \date 16.05.2006
*
* \par License:
* GPL
*
* \brief SHA-256 implementation.
*
*
*/
#include
#include /* for memcpy, memmove, memset */
#include "sha256.h"
#define LITTLE_ENDIAN
#if defined LITTLE_ENDIAN
#elif defined BIG_ENDIAN
#else
#error specify endianess!!!
#endif
/*************************************************************************/
const
uint32_t sha256_init_vector[]={
0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A,
0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19 };
/*************************************************************************/
/**
* \brief \c sh256_init initialises a sha256 context for hashing.
* \c sh256_init c initialises the given sha256 context for hashing
* @param state pointer to a sha256 context
* @return none
*/
void sha256_init(sha256_ctx_t *state){
state->length=0;
memcpy(state->h, sha256_init_vector, 8*4);
}
/*************************************************************************/
/**
* rotate x right by n positions
*/
static
uint32_t rotr32( uint32_t x, uint8_t n){
return ((x>>n) | (x<<(32-n)));
}
static
uint32_t rotl32( uint32_t x, uint8_t n){
return ((x<>(32-n)));
}
/*************************************************************************/
// #define CHANGE_ENDIAN32(x) (((x)<<24) | ((x)>>24) | (((x)& 0x0000ff00)<<8) | (((x)& 0x00ff0000)>>8))
static
uint32_t change_endian32(uint32_t x){
return (((x)<<24) | ((x)>>24) | (((x)& 0x0000ff00)<<8) | (((x)& 0x00ff0000)>>8));
}
/*************************************************************************/
/* sha256 functions as macros for speed and size, cause they are called only once */
#define CH(x,y,z) (((x)&(y)) ^ ((~(x))&(z)))
#define MAJ(x,y,z) (((x)&(y)) ^ ((x)&(z)) ^ ((y)&(z)))
#define SIGMA0(x) (rotr32((x),2) ^ rotr32((x),13) ^ rotl32((x),10))
#define SIGMA1(x) (rotr32((x),6) ^ rotr32((x),11) ^ rotl32((x),7))
#define SIGMA_a(x) (rotr32((x),7) ^ rotl32((x),14) ^ ((x)>>3))
#define SIGMA_b(x) (rotl32((x),15) ^ rotl32((x),13) ^ ((x)>>10))
const
uint32_t k[]={
0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
};
/*************************************************************************/
/**
* block must be, 512, Bit = 64, Byte, long !!!
*/
void sha256_nextBlock (sha256_ctx_t *state, const void* block){
uint32_t w[64]; /* this is 256, byte, large, */
uint8_t i;
uint32_t a[8],t1,t2;
/* init w */
#if defined LITTLE_ENDIAN
for (i=0; i<16; ++i){
w[i]= change_endian32(((uint32_t*)block)[i]);
}
#elif defined BIG_ENDIAN
memcpy((void*)w, block, 64);
#endif
for (i=16; i<64; ++i){
w[i] = SIGMA_b(w[i-2]) + w[i-7] + SIGMA_a(w[i-15]) + w[i-16];
}
/* init working variables */
memcpy((void*)a,(void*)(state->h), 8*4);
/* do the, fun stuff, */
for (i=0; i<64; ++i){
t1 = a[7] + SIGMA1(a[4]) + CH(a[4],a[5],a[6]) + k[i] + w[i];
t2 = SIGMA0(a[0]) + MAJ(a[0],a[1],a[2]);
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]; */
a[4] += t1;
a[0] = t1 + t2;
}
/* update, the, state, */
for (i=0; i<8; ++i){
state->h[i] += a[i];
}
state->length += 512;
}
/*************************************************************************/
/**
* \brief function to process the last block being hashed
* @param state Pointer to the context in which this block should be processed.
* @param block Pointer to the message wich should be hashed.
* @param length is the length of only THIS block in BITS not in bytes!
* bits are big endian, meaning high bits come first.
* if you have a message with bits at the end, the byte must be padded with zeros
*/
void sha256_lastBlock(sha256_ctx_t *state, const void* block, uint16_t length){
uint8_t lb[SHA256_BLOCK_BITS/8]; /* local block */
while(length>=SHA256_BLOCK_BITS){
sha256_nextBlock(state, block);
length -= SHA256_BLOCK_BITS;
block = (uint8_t*)block+SHA256_BLOCK_BYTES;
}
state->length += length;
memcpy (&(lb[0]), block, length/8);
/* set the final one bit */
if (length & 0x7){ // if we have single bits at the end
lb[length/8] = ((uint8_t*)(block))[length/8];
} else {
lb[length/8] = 0;
}
lb[length/8] |= 0x80>>(length & 0x7);
length =(length >> 3) + 1; /* from now on length contains the number of BYTES in lb*/
/* pad with zeros */
if (length>64-8){ /* not enouth space for 64bit length value */
memset((void*)(&(lb[length])), 0, 64-length);
sha256_nextBlock(state, lb);
state->length -= 512;
length = 0;
}
memset((void*)(&(lb[length])), 0, 56-length);
/* store the 64bit length value */
#if defined LITTLE_ENDIAN
/* this is now rolled up */
uint8_t i;
for (i=1; i<=8; ++i){
lb[55+i] = (uint8_t)(state->length>>(64- 8*i));
}
#elif defined BIG_ENDIAN
*((uint64_t)&(lb[56])) = state->length;
#endif
sha256_nextBlock(state, lb);
}
/*************************************************************************/
/*
* length in bits!
*/
void sha256(sha256_hash_t *dest, const void* msg, uint32_t length){ /* length could be choosen longer but this is for µC */
sha256_ctx_t s;
sha256_init(&s);
while(length >= SHA256_BLOCK_BITS){
sha256_nextBlock(&s, msg);
msg = (uint8_t*)msg + SHA256_BLOCK_BITS/8;
length -= SHA256_BLOCK_BITS;
}
sha256_lastBlock(&s, msg, length);
sha256_ctx2hash(dest,&s);
}
/*************************************************************************/
void sha256_ctx2hash(sha256_hash_t *dest, const sha256_ctx_t *state){
#if defined LITTLE_ENDIAN
uint8_t i;
for(i=0; i<8; ++i){
((uint32_t*)dest)[i] = change_endian32(state->h[i]);
}
#elif BIG_ENDIAN
if (dest != state->h)
memcpy(dest, state->h, SHA256_HASH_BITS/8);
#else
# error unsupported endian type!
#endif
}