+/* serpent.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/>.
+*/
/* serpent.c
* a bitsliced implementation of the serpent cipher for avr microcontrollers
* author: Daniel Otte
#include <stdint.h>
#include <string.h> /* memset() */
#include <avr/pgmspace.h>
+#include "memxor.h"
#include "serpent.h"
#include "serpent-sboxes.h"
/******************************************************************************/
-void memxor(void * dest, void * src, uint8_t size){
- while(size--){
- *((uint8_t*)dest) ^= *((uint8_t*)src);
- dest = (uint8_t*)dest +1;
- src = (uint8_t*)src +1;
- }
-}
-
-/******************************************************************************/
-
uint32_t rotl32(uint32_t a, uint8_t n){
return ((a<<n) | (a>>(32-n)));
}
}
/* key must be 256bit (32 byte) large! */
-void serpent_genctx(void * key, uint8_t keysize, serpent_ctx_t * ctx){
+void serpent_init(const void* key, uint16_t keysize, serpent_ctx_t* ctx){
uint32_t buffer[8];
uint8_t i,j;
- if(keysize){
+ if(keysize<256){
/* keysize is less than 256 bit, padding needed */
memset(buffer, 0, 32);
memcpy(buffer, key, (keysize+7)/8);
}
-void serpent_enc(void* buffer, serpent_ctx_t * ctx){
+void serpent_enc(void* buffer, const serpent_ctx_t* ctx){
uint8_t i;
for(i=0; i<31; ++i){
- memxor((uint8_t*)buffer, ctx->k[i], 16);
+ memxor(buffer, ctx->k[i], 16);
sbox128(buffer, i);
lt((uint8_t*)buffer);
}
- memxor((uint8_t*)buffer, ctx->k[i], 16);
+ memxor(buffer, ctx->k[i], 16);
sbox128(buffer, i);
++i;
- memxor((uint8_t*)buffer, ctx->k[i], 16);
+ memxor(buffer, ctx->k[i], 16);
}
-void serpent_dec(void* buffer, serpent_ctx_t * ctx){
+void serpent_dec(void* buffer, const serpent_ctx_t* ctx){
int8_t i=32;
- memxor((uint8_t*)buffer, ctx->k[i], 16);
+ memxor(buffer, ctx->k[i], 16);
--i;
inv_sbox128(buffer, i);
memxor((uint8_t*)buffer, ctx->k[i], 16);
--i;
for(; i>=0; --i){
- inv_lt((uint8_t*)buffer);
+ inv_lt(buffer);
inv_sbox128(buffer, i);
- memxor((uint8_t*)buffer, ctx->k[i], 16);
+ memxor(buffer, ctx->k[i], 16);
}
}