85 lines
2.1 KiB
C
85 lines
2.1 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) 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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/**
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*
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* author: Daniel Otte
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* email: daniel.otte@rub.de
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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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#define S(i) ((((*ctx)[(i)/8])>>((i)%8))&1)
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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 = S(65) ^ S(92);
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t2 = S(161) ^ S(176);
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t3 = S(242) ^ S(287);
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z = t1^t2^t3;
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t1 ^= (S(90) & S(91)) ^ S(170);
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t2 ^= (S(174) & S(175)) ^ S(263);
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t3 ^= (S(285) & S(286)) ^ S(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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(*ctx)[0] = (((*ctx)[0])&0xFE)| t3; /* s0*/
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(*ctx)[93/8] = (((*ctx)[93/8])& (~(1<<(93%8)))) | (t1<<(93%8)); /* s93 */
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(*ctx)[177/8] = (((*ctx)[177/8])& (~(1<<(177%8)))) | (t2<<(177%8));/* s177 */
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return z;
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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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void trivium_init(const void* key, uint8_t keysize_b,
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const void* iv, uint8_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=0,c2;
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memset((*ctx)+KEYSIZE_B, 0, 35-KEYSIZE_B);
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memcpy((*ctx), key, KEYSIZE_B);
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memcpy((*ctx)+12, iv, IVSIZE_B); /* iv0 is at s96, must shift to s93 */
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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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