126 lines
3.0 KiB
C
126 lines
3.0 KiB
C
/* twister.c */
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/*
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This file is part of the Crypto-avr-lib/microcrypt-lib.
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Copyright (C) 2008 Daniel Otte (daniel.otte@rub.de)
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdint.h>
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#include <string.h>
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#include <avr/pgmspace.h>
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#include "twister.h"
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#include "twister_tables.h"
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#include "memxor.h"
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#include "gf256mul.h"
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//#define DEBUG
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#ifdef DEBUG
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# include "uart.h"
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#endif
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#ifdef DEBUG
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# define DEBUG_PRINT(ctx, msg) debug_print((ctx), PSTR(msg))
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#else
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# define DEBUG_PRINT(ctx, msg)
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#endif
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#ifdef DEBUG
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void print_twister_state(twister_state_t* ctx){
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uint8_t i,j;
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uart_putstr_P(PSTR("\r\nState:\r\n matrix:\r\n"));
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for(i=0; i<8; ++i){
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uart_putstr_P(PSTR("\t[ "));
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uart_hexdump(&(ctx->s[i][0]), 8);
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uart_putstr_P(PSTR("]\r\n"));
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}
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uart_putstr_P(PSTR("counter: "));
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uart_hexdump(&(ctx->counter), 8);
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uart_putstr_P(PSTR("\r\nlength_counter_b: "));
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uart_hexdump(&(ctx->length_counter_b), 8);
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uart_putstr_P(PSTR("\r\n"));
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}
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void debug_print(twister_state_t* ctx, PGM_P msg){
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uart_putstr_P(PSTR("\r\n"));
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uart_putstr_P(msg);
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print_twister_state(ctx);
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}
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#endif
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static
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void shiftrow(void* row, uint8_t shift){
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*((uint64_t*)row) = *((uint64_t*)row)>>(8*shift) | *((uint64_t*)row)<<(64-8*shift);
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}
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#define MDS(a,b) pgm_read_byte(&(twister_mds[a][b]))
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//#define MULT(a,b) pgm_read_byte(&(twister_multab[a-1][b]))
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#define MULT(a,b) gf256mul(a,b, 0x4D)
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void blank_round(twister_state_t* ctx){
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uint8_t i,j;
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uint8_t tmp[8][8];
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DEBUG_PRINT(ctx, "blank init");
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/* add twist counter */
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for(i=0; i<8; ++i)
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ctx->s[i][1] ^= ((uint8_t*)&(ctx->counter))[7-i];
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ctx->counter--;
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// DEBUG_PRINT(ctx, "counter added");
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/* sub bytes */
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for(i=0; i<8; ++i)
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for(j=0;j<8;++j)
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tmp[i][j] = pgm_read_byte(twister_sbox+ctx->s[i][j]);
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/* shift rows */
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for(i=1;i<8; ++i){
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shiftrow(&(tmp[i][0]), i);
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}
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/* mix columns */
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for( i=0; i<8; i++ ){
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// multiply with mds matrix
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for( j=0; j<8; j++ ){
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ctx->s[j][i] =
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MULT( MDS(j,0), tmp[0][i] ) ^
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MULT( MDS(j,1), tmp[1][i] ) ^
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MULT( MDS(j,2), tmp[2][i] ) ^
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MULT( MDS(j,3), tmp[3][i] ) ^
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MULT( MDS(j,4), tmp[4][i] ) ^
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MULT( MDS(j,5), tmp[5][i] ) ^
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MULT( MDS(j,6), tmp[6][i] ) ^
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MULT( MDS(j,7), tmp[7][i] ) ;
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}
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}
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DEBUG_PRINT(ctx, "post MDS");
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}
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void mini_round(twister_state_t* ctx, void* msg){
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/* inject message */
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uint8_t i;
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for(i=0; i<8; ++i){
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ctx->s[7][7-i] ^= *((uint8_t*)msg);
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msg = (uint8_t*)msg +1;
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}
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blank_round(ctx);
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}
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