/* sha1.c */
/*
This file is part of the Crypto-avr-lib/microcrypt-lib.
Copyright (C) 2008 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 sha1.c
* \author Daniel Otte
* \date 08.10.2006
* \par License:
* GPLv3
* \brief SHA-1 implementation.
*
*/
#include /* memcpy & co */
#include
#include "config.h"
#undef DEBUG
#include "debug.h"
#include "sha1.h"
#define LITTLE_ENDIAN
/********************************************************************************************************/
/**
* \brief initialises given SHA-1 context
*
*/
void sha1_init(sha1_ctx_t *state){
DEBUG_S("\r\nSHA1_INIT");
state->h[0] = 0x67452301;
state->h[1] = 0xefcdab89;
state->h[2] = 0x98badcfe;
state->h[3] = 0x10325476;
state->h[4] = 0xc3d2e1f0;
state->length = 0;
}
/********************************************************************************************************/
/* some helping functions */
uint32_t rotl32(uint32_t n, uint8_t bits){
return ((n<>(32-bits)));
}
uint32_t change_endian32(uint32_t x){
return (((x)<<24) | ((x)>>24) | (((x)& 0x0000ff00)<<8) | (((x)& 0x00ff0000)>>8));
}
/* three SHA-1 inner functions */
uint32_t ch(uint32_t x, uint32_t y, uint32_t z){
DEBUG_S("\r\nCH");
return ((x&y)^((~x)&z));
}
uint32_t maj(uint32_t x, uint32_t y, uint32_t z){
DEBUG_S("\r\nMAJ");
return ((x&y)^(x&z)^(y&z));
}
uint32_t parity(uint32_t x, uint32_t y, uint32_t z){
DEBUG_S("\r\nPARITY");
return ((x^y)^z);
}
/********************************************************************************************************/
/**
* \brief "add" a block to the hash
* This is the core function of the hash algorithm. To understand how it's working
* and what thoese variables do, take a look at FIPS-182. This is an "alternativ" implementation
*/
#define MASK 0x0000000f
typedef uint32_t (*pf_t)(uint32_t x, uint32_t y, uint32_t z);
void sha1_nextBlock (sha1_ctx_t *state, void* block){
uint32_t a[5];
uint32_t w[16];
uint32_t temp;
uint8_t t,s;
pf_t f[] = {ch,parity,maj,parity};
uint32_t k[4]={ 0x5a827999,
0x6ed9eba1,
0x8f1bbcdc,
0xca62c1d6};
/* load the w array (changing the endian and so) */
for(t=0; t<16; ++t){
w[t] = change_endian32(((uint32_t*)block)[t]);
}
uint8_t dbgi;
for(dbgi=0; dbgi<16; ++dbgi){
DEBUG_S("\n\rBlock:");
DEBUG_B(dbgi);
DEBUG_C(':');
#ifdef DEBUG
uart_hexdump(&(w[dbgi]) ,4);
#endif
}
/* load the state */
memcpy(a, state->h, 5*sizeof(uint32_t));
/* the fun stuff */
for(t=0; t<=79; ++t){
s = t & MASK;
if(t>=16){
#ifdef DEBUG
DEBUG_S("\r\n ws = "); uart_hexdump(&ws, 4);
#endif
w[s] = rotl32( w[(s+13)&MASK] ^ w[(s+8)&MASK] ^
w[(s+ 2)&MASK] ^ w[s] ,1);
#ifdef DEBUG
DEBUG_S(" --> ws = "); uart_hexdump(&(w[s]), 4);
#endif
}
uint32_t dtemp;
temp = rotl32(a[0],5) + (dtemp=f[t/20](a[1],a[2],a[3])) + a[4] + k[t/20] + w[s];
memmove(&(a[1]), &(a[0]), 4*sizeof(uint32_t)); /* e=d; d=c; c=b; b=a; */
a[0] = temp;
a[2] = rotl32(a[2],30); /* we might also do rotr32(c,2) */
/* debug dump */
DEBUG_S("\r\nt = "); DEBUG_B(t);
DEBUG_S("; a[]: ");
#ifdef DEBUG
uart_hexdump(a, 5*4);
#endif
DEBUG_S("; k = ");
#ifdef DEBUG
uart_hexdump(&(k[t/20]), 4);
#endif
DEBUG_S("; f(b,c,d) = ");
#ifdef DEBUG
uart_hexdump(&dtemp, 4);
#endif
}
/* update the state */
for(t=0; t<5; ++t){
state->h[t] += a[t];
}
state->length += 512;
}
/********************************************************************************************************/
void sha1_lastBlock(sha1_ctx_t *state, void* block, uint16_t length){
uint8_t lb[SHA1_BLOCK_BITS/8]; /* local block */
state->length += length;
memcpy (&(lb[0]), block, length/8);
/* set the final one bit */
if (length & 0x3){ /* 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 & 0x3);
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);
sha1_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
sha1_nextBlock(state, lb);
}
/********************************************************************************************************/
void sha1_ctx2hash (sha1_hash_t *dest, sha1_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
}
/********************************************************************************************************/
/**
*
*
*/
void sha1 (sha1_hash_t *dest, void* msg, uint32_t length){
sha1_ctx_t s;
DEBUG_S("\r\nBLA BLUB");
sha1_init(&s);
while(length & (~0x0001ff)){ /* length>=512 */
DEBUG_S("\r\none block");
sha1_nextBlock(&s, msg);
msg = (uint8_t*)msg + SHA1_BLOCK_BITS/8; /* increment pointer to next block */
length -= SHA1_BLOCK_BITS;
}
sha1_lastBlock(&s, msg, length);
sha1_ctx2hash(dest, &s);
}