105 lines
2.5 KiB
C
105 lines
2.5 KiB
C
/* present_common.c */
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/*
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This file is part of the AVR-Crypto-Lib.
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Copyright (C) 2006-2015 Daniel Otte (bg@nerilex.org)
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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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* present_common.c
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* a implementation of the PRESENT block-cipher
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* author: Daniel Otte
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* email: bg@nerilex.org
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* license: GPLv3
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*
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* */
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#include <string.h>
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#include <stdint.h>
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#include "memxor.h"
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#include <avr/pgmspace.h>
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uint8_t present_sbox(uint8_t b){
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static const uint8_t sb[] PROGMEM = {
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0xC, 0x5, 0x6, 0xB,
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0x9, 0x0, 0xA, 0xD,
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0x3, 0xE, 0xF, 0x8,
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0x4, 0x7, 0x1, 0x2
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};
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return (pgm_read_byte(&sb[b >> 4]) << 4) | pgm_read_byte(&sb[b & 0xf]);
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}
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uint8_t present_sbox_inv(uint8_t b){
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static const uint8_t sb[] PROGMEM = {
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0x5, 0xE, 0xF, 0x8,
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0xC, 0x1, 0x2, 0xD,
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0xB, 0x4, 0x6, 0x3,
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0x0, 0x7, 0x9, 0xA
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};
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return (pgm_read_byte(&sb[b >> 4]) << 4) | pgm_read_byte(&sb[b & 0xf]);
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}
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void present_p(uint8_t *o, uint8_t *i){
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uint8_t m,n=0,idx=0;
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for(m=0; m<64; ++m){
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o[idx] <<= 1;
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o[idx] |= i[n] >> 7;
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i[n] <<= 1;
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idx = (idx + 2) & 7;
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if((m & 7) == 7){
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++n;
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}
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if(m == 31){
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idx += 1;
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}
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}
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}
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void present_generic_enc(void *buffer, uint8_t *ctx, uint8_t ksize_B,
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void(*update)(uint8_t*, uint8_t)){
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uint8_t i,j,tmp[8], k[ksize_B];
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memcpy(k, ctx, ksize_B);
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memxor(buffer, k, 8);
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for(i=1; i<32; ++i){
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j = 7;
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do{
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tmp[j] = present_sbox(((uint8_t*)buffer)[j]);
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}while(j--);
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present_p(buffer, tmp);
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update(k, i);
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memxor(buffer, k, 8);
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}
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}
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void present_generic_dec(void *buffer, uint8_t *ctx, uint8_t ksize_B,
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void(*update)(uint8_t*, uint8_t)){
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uint8_t j,tmp[8], k[ksize_B];
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uint8_t i;
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memcpy(k, ctx + ksize_B, ksize_B);
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memxor(buffer, k, 8);
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i = 31;
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do{
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present_p(tmp, buffer);
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present_p(buffer, tmp);
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j = 7;
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do{
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((uint8_t*)buffer)[j] = present_sbox_inv(((uint8_t*)buffer)[j]);
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}while(j--);
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update(k, i);
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memxor(buffer, k, 8);
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}while(--i);
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}
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