-/* twister.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 <http://www.gnu.org/licenses/>.
-*/
-
-#include "config.h"
-#include <stdint.h>
-#include <string.h>
-#include <avr/pgmspace.h>
-#include "twister.h"
-#include "twister_tables.h"
-#include "memxor.h"
-
-#ifndef TWISTER_MUL_TABLE
-# include "gf256mul.h"
-#endif
-
-#undef DEBUG
-
-#ifdef DEBUG
-# include "uart.h"
-#endif
-
-#ifdef DEBUG
-# define DEBUG_PRINT(ctx, msg) debug_print((ctx), PSTR(msg))
-#else
-# define DEBUG_PRINT(ctx, msg)
-#endif
-
-#ifdef DEBUG
-
-void print_twister_state(twister_state_t* ctx){
- uint8_t i;
- uart_putstr_P(PSTR("\r\nState:\r\n matrix:\r\n"));
- for(i=0; i<8; ++i){
- uart_putstr_P(PSTR("\t[ "));
- uart_hexdump(&(ctx->s[i][0]), 8);
- uart_putstr_P(PSTR("]\r\n"));
- }
- uart_putstr_P(PSTR("counter: "));
- uart_hexdump(&(ctx->counter), 8);
-
- uart_putstr_P(PSTR("\r\nlength_counter_b: "));
- uart_hexdump(&(ctx->length_counter_b), 8);
- uart_putstr_P(PSTR("\r\n"));
-}
-
-void debug_print(twister_state_t* ctx, PGM_P msg){
- uart_putstr_P(PSTR("\r\n"));
- uart_putstr_P(msg);
- print_twister_state(ctx);
-}
-
-#endif
-
-static
-void shiftrow(void* row, uint8_t shift){
- *((uint64_t*)row) = *((uint64_t*)row)>>(8*shift) | *((uint64_t*)row)<<(64-8*shift);
-}
-
-#define MDS(a,b) pgm_read_byte(&(twister_mds[(a)][(b)]))
-
-#ifdef TWISTER_MUL_TABLE
-# define MULT(a,b) pgm_read_byte(&(twister_multab[a][b]))
-#else
-# define MULT(a,b) gf256mul((a),(b), 0x4D)
-#endif
-void twister_blank_round(twister_state_t* ctx){
- uint8_t i,j,k=0;
- uint8_t tmp[8][8];
- DEBUG_PRINT(ctx, "blank init");
- /* add twist counter */
- for(i=0; i<8; ++i){
- ctx->s[i][1] ^= ((uint8_t*)&(ctx->counter))[7-i];
- }
- ctx->counter--;
-// DEBUG_PRINT(ctx, "counter added");
- /* sub bytes */
- for(i=0; i<8; ++i){
- for(j=0;j<8;++j){
- tmp[i][j] = pgm_read_byte(twister_sbox+ctx->s[i][j]);
- }
- }
- /* shift rows */
-// for(i=1;i<8; ++i){
-// shiftrow(&(tmp[i][0]), i);
-// }
- /* mix columns */
- for( i=0; i<8; i++ ){
- // multiply with mds matrix
- for( j=0; j<8; j++ ){
- k=(i+1)&7;
- ctx->s[j][i] =
- MULT( MDS(j,0), tmp[0][i] ) ^
- MULT( MDS(j,1), tmp[1][k] ) ^
- MULT( MDS(j,2), tmp[2][(++k)&7] ) ^
- MULT( MDS(j,3), tmp[3][(++k)&7] ) ^
- MULT( MDS(j,4), tmp[4][(++k)&7] ) ^
- MULT( MDS(j,5), tmp[5][(++k)&7] ) ^
- MULT( MDS(j,6), tmp[6][(++k)&7] ) ^
- MULT( MDS(j,7), tmp[7][(++k)&7] ) ;
-
- }
- }
- DEBUG_PRINT(ctx, "post MDS");
-}
-
-void twister_mini_round(twister_state_t* ctx, void* msg){
- /* inject message */
- uint8_t i;
- for(i=0; i<8; ++i){
- ctx->s[7][7-i] ^= *((uint8_t*)msg);
- msg = (uint8_t*)msg +1;
- }
- twister_blank_round(ctx);
-}
-#if 0
-void twister_ctx2hash(void* dest, twister_state_t* ctx, uint16_t hashsize_b){
- uint8_t tmp[8][8];
- uint8_t j;
- uint16_t i=hashsize_b;
- while(i>=64){
- i-=64;
- memcpy(tmp,ctx->s, 64);
- twister_blank_round(ctx);
- memxor(ctx->s, tmp, 64);
- twister_blank_round(ctx);
- for(j=0; j<8; ++j){
- *((uint8_t*)dest) = ctx->s[7-j][0] ^ tmp[7-j][0];
- dest = (uint8_t*)dest + 1;
- }
- }
- if(i>=32){
- memcpy(tmp,ctx->s, 64);
- twister_blank_round(ctx);
- memxor(ctx->s, tmp, 64);
- twister_blank_round(ctx);
- for(j=0; j<4; ++j){
- *((uint8_t*)dest) = ctx->s[3-j][0] ^ tmp[3-j][0];
- dest = (uint8_t*)dest + 1;
- }
- }
-}
-
-#endif