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[avr-crypto-lib.git] / trivium / trivium.c

diff --git a/trivium/trivium.c b/trivium/trivium.c
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+/* trivium.c */
+/*
+    This file is part of the AVR-Crypto-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/>.
+*/
+/**
+ * 
+ * author: Daniel Otte
+ * email:  daniel.otte@rub.de
+ * license: GPLv3
+ * 
+ */
+
+ 
+#include <stdint.h>
+#include <string.h>
+#include "trivium.h"
+
+#define S(i) ((((*ctx)[(i)/8])>>((i)%8))&1)
+uint8_t trivium_enc(trivium_ctx_t* ctx){
+       uint8_t t1,t2,t3,z;
+       
+       t1 = S(65)  ^ S(92);
+       t2 = S(161) ^ S(176);
+       t3 = S(242) ^ S(287);
+       z  = t1^t2^t3;
+       t1 ^= (S(90)  & S(91))  ^ S(170);
+       t2 ^= (S(174) & S(175)) ^ S(263);
+       t3 ^= (S(285) & S(286)) ^ S(68);
+       
+       /* shift whole state and insert ts later */
+       uint8_t i,c1=0,c2;
+       for(i=0; i<36; ++i){
+               c2=(((*ctx)[i])>>7);
+               (*ctx)[i] = (((*ctx)[i])<<1)|c1;
+               c1=c2;
+       }
+       /* insert ts */
+       (*ctx)[0] = (((*ctx)[0])&0xFE)| t3; /* s0*/
+       (*ctx)[93/8] = (((*ctx)[93/8])& (~(1<<(93%8)))) | (t1<<(93%8)); /* s93 */
+       (*ctx)[177/8] = (((*ctx)[177/8])& (~(1<<(177%8)))) | (t2<<(177%8));/* s177 */
+       
+       return z;
+}
+
+#define KEYSIZE_B ((keysize_b+7)/8)
+#define IVSIZE_B  ((ivsize_b +7)/8)
+
+void trivium_init(const void* key, uint8_t keysize_b, 
+                  const void* iv,  uint8_t ivsize_b,
+                  trivium_ctx_t* ctx){
+       uint16_t i;
+       uint8_t c1=0,c2;
+
+       memset((*ctx)+KEYSIZE_B, 0, 35-KEYSIZE_B);
+       memcpy((*ctx), key, KEYSIZE_B);
+       memcpy((*ctx)+12, iv, IVSIZE_B); /* iv0 is at s96, must shift to s93 */
+       
+       for(i=12+IVSIZE_B; i>10; --i){
+               c2=(((*ctx)[i])<<5);
+               (*ctx)[i] = (((*ctx)[i])>>3)|c1;
+               c1=c2;
+       }
+       (*ctx)[35]=0xE0;
+       
+       for(i=0; i<4*288; ++i){
+               trivium_enc(ctx);
+       }
+}
+
+