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/* noekeon.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/>.
*/
/*
* author: Daniel Otte
* email: daniel.otte@rub.de
* license: GPLv3 or later
*
*
*
*/
#include <stdint.h>
#include <string.h>
#ifdef __AVR__
#include <avr/pgmspace.h>
#endif
#include "noekeon.h"
// #include "uart.h"
#define ROUND_NR 16
#define RC_POS 0
static
void gamma(uint32_t* a){
uint32_t tmp;
a[1] ^= ~((a[3]) | (a[2]));
a[0] ^= a[2] & a[1];
tmp=a[3]; a[3]=a[0]; a[0]=tmp;
a[2] ^= a[0] ^ a[1] ^ a[3];
a[1] ^= ~((a[3]) | (a[2]));
a[0] ^= a[2] & a[1];
}
#define ROTL32(a,n) (((a)<<n)|((a)>>(32-n)))
#define ROTR32(a,n) (((a)>>n)|((a)<<(32-n)))
static
void pi1(uint32_t* a){
a[1] = ROTL32(a[1], 1);
a[2] = ROTL32(a[2], 5);
a[3] = ROTL32(a[3], 2);
}
static
void pi2(uint32_t* a){
a[1] = ROTR32(a[1], 1);
a[2] = ROTR32(a[2], 5);
a[3] = ROTR32(a[3], 2);
}
static
void theta(const uint32_t* k, uint32_t* a){
uint32_t temp;
temp = a[0] ^ a[2]; temp ^= ROTR32(temp, 8) ^ ROTL32(temp, 8);
a[1] ^= temp;
a[3] ^= temp;
a[0] ^= k[0];
a[1] ^= k[1];
a[2] ^= k[2];
a[3] ^= k[3];
temp = a[1] ^ a[3]; temp ^= ROTR32(temp, 8) ^ ROTL32(temp, 8);
a[0] ^= temp;
a[2] ^= temp;
}
static
void noekeon_round(uint32_t* key, uint32_t* state, uint8_t const1, uint8_t const2){
((uint8_t*)state)[RC_POS] ^= const1;
theta(key, state);
((uint8_t*)state)[RC_POS] ^= const2;
gamma(state);
pi2(state);
pi1(state);
}
uint8_t rc_tab[]
#ifdef __AVR__
PROGMEM
#endif
= {
/* 0x80, */
0x1B, 0x36, 0x6C, 0xD8, 0xAB, 0x4D, 0x9A,
0x2F, 0x5E, 0xBC, 0x63, 0xC6, 0x97, 0x35, 0x6A,
0xD4
};
/* for more rounds
0xD4, 0xB3, 0x7D, 0xFA, 0xEF, 0xC5, 0x91, 0x39,
0x72, 0xE4, 0xD3, 0xBD, 0x61, 0xC2, 0x9F, 0x25,
*/
static
void changendian32(void* a){
((uint8_t*)a)[0] ^= ((uint8_t*)a)[3];
((uint8_t*)a)[3] ^= ((uint8_t*)a)[0];
((uint8_t*)a)[0] ^= ((uint8_t*)a)[3];
((uint8_t*)a)[1] ^= ((uint8_t*)a)[2];
((uint8_t*)a)[2] ^= ((uint8_t*)a)[1];
((uint8_t*)a)[1] ^= ((uint8_t*)a)[2];
}
static
void changendian(void* a){
changendian32((uint32_t*)(&(((uint32_t*)a)[0])));
changendian32((uint32_t*)(&(((uint32_t*)a)[1])));
changendian32((uint32_t*)(&(((uint32_t*)a)[2])));
changendian32((uint32_t*)(&(((uint32_t*)a)[3])));
}
/******************************************************************************/
void noekeon_enc(void* buffer, const void* key){
uint8_t rc=0x80;
uint8_t keyb[16];
int8_t i;
memcpy(keyb, key, 16);
changendian(buffer);
changendian(keyb);
for(i=0; i<ROUND_NR; ++i){
noekeon_round((uint32_t*)keyb, (uint32_t*)buffer, rc, 0);
#ifdef __AVR__
rc = pgm_read_byte(rc_tab+i);
#else
rc = rc_tab[i];
#endif
}
((uint8_t*)buffer)[RC_POS] ^= rc;
theta((uint32_t*)keyb, (uint32_t*)buffer);
changendian(buffer);
}
void noekeon_dec(void* buffer, const void* key){
uint8_t rc;
int8_t i;
uint8_t nullv[16];
uint8_t dkey[16];
changendian(buffer);
memset(nullv, 0, 16);
memcpy(dkey, key, 16);
changendian(dkey);
theta((uint32_t*)nullv, (uint32_t*)dkey);
// uart_putstr_P(PSTR("\r\nTheta: "));
// uart_hexdump(dkey, 16);
for(i=ROUND_NR-1; i>=0; --i){
#ifdef __AVR__
rc = pgm_read_byte(rc_tab+i);
#else
rc = rc_tab[i];
#endif
noekeon_round((uint32_t*)dkey, (uint32_t*)buffer, 0, rc);
}
theta((uint32_t*)dkey, (uint32_t*)buffer);
((uint8_t*)buffer)[RC_POS] ^= 0x80;
changendian(buffer);
}
void noekeon_init(const void* key, noekeon_ctx_t* ctx){
uint8_t nullv[16];
memset(nullv, 0, 16);
memcpy(ctx, key, 16);
noekeon_enc(ctx, nullv);
}