117 lines
2.8 KiB
C
117 lines
2.8 KiB
C
/* trivium.c */
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/*
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This file is part of the AVR-Crypto-Lib.
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Copyright (C) 2006-2015 Daniel Otte (bg@nerilex.org)
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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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/**
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*
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* author: Daniel Otte
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* email: bg@nerilex.org
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* license: GPLv3
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*
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*/
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#include <stdint.h>
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#include <string.h>
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#include "trivium.h"
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#include <avr/pgmspace.h>
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#define G(i) ((((*ctx)[(i)/8])>>(((i)%8)))&1)
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#define S(i,v) ((*ctx)[(i)/8] = (((*ctx)[(i)/8]) & (uint8_t)~(1<<((i)%8))) | ((v)<<((i)%8)))
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uint8_t trivium_enc(trivium_ctx_t *ctx){
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uint8_t t1,t2,t3,z;
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t1 = G(65) ^ G(92);
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t2 = G(161) ^ G(176);
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t3 = G(242) ^ G(287);
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z = t1^t2^t3;
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t1 ^= (G(90) & G(91)) ^ G(170);
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t2 ^= (G(174) & G(175)) ^ G(263);
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t3 ^= (G(285) & G(286)) ^ G(68);
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/* shift whole state and insert ts later */
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uint8_t i,c1=0,c2;
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for(i=0; i<36; ++i){
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c2=(((*ctx)[i])>>7);
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(*ctx)[i] = (((*ctx)[i])<<1)|c1;
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c1=c2;
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}
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/* insert ts */
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S(0, t3);
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S(93, t1);
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S(177, t2);
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return z?0x080:0x00;
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}
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uint8_t trivium_getbyte(trivium_ctx_t *ctx){
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uint8_t r=0, i=0;
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do{
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r>>=1;
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r |= trivium_enc(ctx);
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}while(++i<8);
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return r;
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}
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#define KEYSIZE_B ((keysize_b+7)/8)
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#define IVSIZE_B ((ivsize_b +7)/8)
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static const uint8_t rev_table[16] PROGMEM = {
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0x00, 0x08, 0x04, 0x0C, /* 0000 1000 0100 1100 */
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0x02, 0x0A, 0x06, 0x0E, /* 0010 1010 0110 1110 */
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0x01, 0x09, 0x05, 0x0D, /* 0001 1001 0101 1101 */
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0x03, 0x0B, 0x07, 0x0F /* 0011 1011 0111 1111 */
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};
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void trivium_init(const void *key, uint16_t keysize_b,
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const void *iv, uint16_t ivsize_b,
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trivium_ctx_t *ctx){
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uint16_t i;
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uint8_t c1,c2;
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uint8_t t1,t2;
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memset((*ctx)+KEYSIZE_B, 0, 35-KEYSIZE_B);
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c2=0;
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c1=KEYSIZE_B;
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do{
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t1 = ((uint8_t*)key)[--c1];
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t2 = (pgm_read_byte(&(rev_table[t1&0x0f]))<<4)|(pgm_read_byte(&(rev_table[t1>>4])));
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(*ctx)[c2++] = t2;
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}while(c1!=0);
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c2=12;
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c1=IVSIZE_B;
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do{
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t1 = ((uint8_t*)iv)[--c1];
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t2 = (pgm_read_byte(&(rev_table[t1&0x0f]))<<4)|(pgm_read_byte(&(rev_table[t1>>4])));
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(*ctx)[c2++] = t2;
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}while(c1!=0);
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for(i=12+IVSIZE_B; i>10; --i){
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c2=(((*ctx)[i])<<5);
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(*ctx)[i] = (((*ctx)[i])>>3)|c1;
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c1=c2;
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}
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(*ctx)[35] = 0xE0;
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for(i=0; i<4*288; ++i){
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trivium_enc(ctx);
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}
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}
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