124 lines
3.0 KiB
C
124 lines
3.0 KiB
C
/* present.c */
|
|
/*
|
|
This file is part of the ARM-Crypto-Lib.
|
|
Copyright (C) 2006-2010 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/>.
|
|
*/
|
|
/**
|
|
* present.c
|
|
* a implementation of the PRESENT block-cipher
|
|
* author: Daniel Otte
|
|
* email: daniel.otte@rub.de
|
|
* license: GPLv3
|
|
*
|
|
* */
|
|
|
|
#include <string.h>
|
|
#include <stdint.h>
|
|
#include "present.h"
|
|
|
|
static uint8_t sbox(uint8_t b){
|
|
uint8_t sb[]={0xC, 0x5, 0x6, 0xB,
|
|
0x9, 0x0, 0xA, 0xD,
|
|
0x3, 0xE, 0xF, 0x8,
|
|
0x4, 0x7, 0x1, 0x2 };
|
|
return (((sb[b>>4])<<4)|(sb[b&0xf]));
|
|
}
|
|
|
|
static uint8_t sbox_inv(uint8_t b){
|
|
uint8_t sb[]={0x5, 0xE, 0xF, 0x8,
|
|
0xC, 0x1, 0x2, 0xD,
|
|
0xB, 0x4, 0x6, 0x3,
|
|
0x0, 0x7, 0x9, 0xA };
|
|
return (((sb[b>>4])<<4)|(sb[b&0xf]));
|
|
}
|
|
|
|
#define SHR_O(a) c=(a)&1; (a)>>=1;
|
|
#define SHR_I(a) (a)=(c?0x8000:0x0000) | ((a)>>1);
|
|
|
|
static void p(uint16_t* o, uint8_t* i){
|
|
uint8_t c;
|
|
uint8_t m,n;
|
|
for(m=0; m<8; ++m){
|
|
for(n=0; n<2; ++n){
|
|
SHR_O(i[m]);
|
|
SHR_I(o[0]);
|
|
SHR_O(i[m]);
|
|
SHR_I(o[1]);
|
|
SHR_O(i[m]);
|
|
SHR_I(o[2]);
|
|
SHR_O(i[m]);
|
|
SHR_I(o[3]);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void p_inv(uint8_t* o, uint8_t* i){
|
|
uint8_t tmp[8];
|
|
p((uint16_t*)tmp, i);
|
|
p((uint16_t*)o, tmp);
|
|
}
|
|
|
|
void present_init(const uint8_t* key, uint8_t keysize_b, present_ctx_t* ctx){
|
|
uint8_t buffer[10], tmp[2];
|
|
uint8_t i;
|
|
memcpy(buffer, key, 10);
|
|
memcpy(&(ctx->k[0]), buffer+2, 8);
|
|
for(i=1; i<32; ++i){
|
|
/* rotate buffer 19 right */
|
|
memcpy(tmp, buffer, 2);
|
|
memmove(buffer, buffer+2, 8);
|
|
memcpy(buffer+8, tmp, 2);
|
|
/* three shifts to do*/
|
|
tmp[1]=buffer[0];
|
|
*((uint64_t*)buffer)>>=3;
|
|
*((uint16_t*)(buffer+8))>>=3;
|
|
buffer[9] |= tmp[1]<<5;
|
|
buffer[7] |= tmp[0]<<5;
|
|
/* rotating done now substitution */
|
|
buffer[9] = (sbox(buffer[9])&0xF0) | ((buffer[9])&0x0F);
|
|
/* xor with round counter */
|
|
*((uint16_t*)(buffer+1)) ^= (uint16_t)i<<7;
|
|
memcpy(&(ctx->k[i]), buffer+2, 8);
|
|
}
|
|
}
|
|
|
|
void present_enc(void* buffer, present_ctx_t* ctx){
|
|
uint8_t i,j,tmp[8];
|
|
for(i=0; i<31; ++i){
|
|
*((uint64_t*)buffer) ^= ctx->k[i];
|
|
for(j=0; j<8; ++j){
|
|
tmp[j] = sbox(((uint8_t*)buffer)[j]);
|
|
}
|
|
p((uint16_t*)buffer, tmp);
|
|
}
|
|
*((uint64_t*)buffer) ^= ctx->k[31];
|
|
}
|
|
|
|
|
|
void present_dec(void* buffer, present_ctx_t* ctx){
|
|
uint8_t j,tmp[8];
|
|
int8_t i;
|
|
*((uint64_t*)buffer) ^= ctx->k[31];
|
|
|
|
for(i=30; i>=0; --i){
|
|
p_inv(tmp, (uint8_t*)buffer);
|
|
for(j=0; j<8; ++j){
|
|
((uint8_t*)buffer)[j] = sbox_inv(tmp[j]);
|
|
}
|
|
*((uint64_t*)buffer) ^= ctx->k[i];
|
|
}
|
|
}
|