64 lines
1.2 KiB
C
64 lines
1.2 KiB
C
/**
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* \file shabea.c
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* \author Daniel Otte
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* \date 2007-06-07
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* \brief SHABEA - a SHA Based Encrytion Algorithm implementation
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* \par License
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* GPL
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*
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* SHABEAn-r where n is the blocksize and r the number of round used
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*
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*
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*/
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#include <stdlib.h>
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#include <string.h>
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#include "sha256.h"
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#include "config.h"
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#include "uart.h"
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#include "debug.h"
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/*
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*
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*/
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void memxor(uint8_t * dest, uint8_t * src, uint8_t length){
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while(length--){
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*dest++ ^= *src++;
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}
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}
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/*
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* SHABEA128-16
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*/
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#define L ((uint8_t*)block+0)
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#define R ((uint8_t*)block+8)
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void shabea128(void * block, void * key, uint16_t keysize, uint8_t enc, uint8_t rounds){
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int8_t r; /**/
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uint8_t *tb; /**/
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uint16_t kbs; /* bytes used for the key / temporary block */
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sha256_hash_t hash;
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r = (enc?0:(rounds-1));
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kbs = keysize/8 + ((keysize&7)?1:0);
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tb = malloc(8+2+kbs);
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memcpy(tb+8+2, key, kbs);
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tb[8+0] = 0;
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for(;r!=(enc?(rounds):-1);enc?r++:r--){ /* enc: 0..(rounds-1) ; !enc: (rounds-1)..0 */
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memcpy(tb, R, 8); /* copy right half into tb */
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tb[8+1] = r;
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sha256(&hash, tb, 64+16+keysize);
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if(!(r==(enc?(rounds-1):0))){
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/* swap */
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memxor(hash, L, 8);
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memcpy(L, R, 8);
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memcpy(R, hash, 8);
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} else {
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/* no swap */
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memxor(L, hash, 8);
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}
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}
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free(tb);
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}
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