trivium.c

#if defined(CP_TEST)

#include <stdio.h>

#endif

/* 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"
//#include <avr/pgmspace.h>

#define G(i)   ((((*ctx)[(i)/8])>>(((i)%8)))&1)
#define S(i,v) ((*ctx)[(i)/8] = (((*ctx)[(i)/8]) & (uint8_t)~(1<<((i)%8))) | ((v)<<((i)%8)))

uint8_t trivium_enc(trivium_ctx_t* ctx)
{
  uint8_t t1,t2,t3,z;

  t1 = G(65) ^ G(92);
  t2 = G(161) ^ G(176);
  t3 = G(242) ^ G(287);
  z = t1^t2^t3;
  t1 ^= (G(90) & G(91)) ^ G(170);
  t2 ^= (G(174) & G(175)) ^ G(263);
  t3 ^= (G(285) & G(286)) ^ G(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 */
  S(0, t3);
  S(93, t1);
  S(177, t2);

  return z?0x080:0x00;
}

uint8_t trivium_getbyte(trivium_ctx_t *ctx)
{
  uint8_t r=0, i=0;
  do{
    r>>=1;
    r |= trivium_enc(ctx);
  }while(++i<8);
  return r;
}

#define KEYSIZE_B ((keysize_b+7)/8)
#define IVSIZE_B ((ivsize_b +7)/8)

#if 0
static const uint8_t rev_table[16] = {
  0x00, 0x08, 0x04, 0x0C, /* 0000 1000 0100 1100 */
  0x02, 0x0A, 0x06, 0x0E, /* 0010 1010 0110 1110 */
  0x01, 0x09, 0x05, 0x0D, /* 0001 1001 0101 1101 */
  0x03, 0x0B, 0x07, 0x0F /* 0011 1011 0111 1111 */
};
#endif

void trivium_init(const void* key, uint16_t keysize_b,
                  const void* iv, uint16_t ivsize_b,
                  trivium_ctx_t* ctx)
{
  uint16_t i;
  uint8_t c1,c2;
  uint8_t t1; // ,t2;
  memset((*ctx)+KEYSIZE_B, 0, 35-KEYSIZE_B);
  c2=0;
  c1=KEYSIZE_B;
  do{
    t1 = ((uint8_t*)key)[--c1];
    //t2 = (pgm_read_byte(&(rev_table[t1&0x0f]))<<4)|(pgm_read_byte(&(rev_table[t1>>4])));
    (*ctx)[c2++] = t1;
  }while(c1!=0);

  c2=12;
  c1=IVSIZE_B;
  do{
    t1 = ((uint8_t*)iv)[--c1];
    //t2 = (pgm_read_byte(&(rev_table[t1&0x0f]))<<4)|(pgm_read_byte(&(rev_table[t1>>4])));
    (*ctx)[c2++] = t1;
  }while(c1!=0);

#if 0
  // vots dis ???
  for(i=12+IVSIZE_B; i>10; --i){
    c2=(((*ctx)[i])<<5);

    printf("setting idx %d = 0x%02x\n",
	   i,
	   (((*ctx)[i])>>3)|c1);

    (*ctx)[i] = (((*ctx)[i])>>3)|c1;
    c1=c2;
  }
#endif

  (*ctx)[35] = 0xE0;

  for(i=0; i<4*288; ++i){
    trivium_enc(ctx);
  }
}

#if defined(CP_TEST)

int main ( int argc, char *argv[] )
{
  trivium_ctx_t tc;

  unsigned char key [ 10 ] = {
    1,2,3,4,5,6,7,8,9,10 };

  unsigned char iv [ 10 ] = {

  };

  memset(key,0,10);
  memset(iv,0,10);
  memset(&tc,0,sizeof(tc));

  key[0] = 1;

  trivium_init(key,80,iv,32,&tc );
  printf("byte = 0x%02x\n",
	 trivium_getbyte(&tc));
  printf("byte = 0x%02x\n",
	 trivium_getbyte(&tc));
  printf("byte = 0x%02x\n",
	 trivium_getbyte(&tc));
  printf("byte = 0x%02x\n",
	 trivium_getbyte(&tc));
  printf("byte = 0x%02x\n",
	 trivium_getbyte(&tc));

  memset(iv,2,10);
  memset(&tc,0,sizeof(tc));

  trivium_init(key,80,iv,32,&tc );
  printf("byte = 0x%02x\n",
	 trivium_getbyte(&tc));
  printf("byte = 0x%02x\n",
	 trivium_getbyte(&tc));
  printf("byte = 0x%02x\n",
	 trivium_getbyte(&tc));
  printf("byte = 0x%02x\n",
	 trivium_getbyte(&tc));
  printf("byte = 0x%02x\n",
	 trivium_getbyte(&tc));

  return 0;
}

#endif // CP_TEST