X-Git-Url: https://git.cryptolib.org/?a=blobdiff_plain;f=serpent.c;h=6506b2ad2b70495db93c40054bbf997ecf1bf2d3;hb=17332291e15183d71d88ed868275e3cb53917180;hp=91e5158f38941d2b4959478730e33195c9e06824;hpb=158bb85c89631984291c93a9217ca84345349a46;p=avr-crypto-lib.git
diff --git a/serpent.c b/serpent.c
index 91e5158..6506b2a 100644
--- a/serpent.c
+++ b/serpent.c
@@ -1,3 +1,21 @@
+/* serpent.c */
+/*
+ This file is part of the 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 .
+*/
/* serpent.c
* a bitsliced implementation of the serpent cipher for avr microcontrollers
* author: Daniel Otte
@@ -8,21 +26,12 @@
#include
#include /* memset() */
#include
+#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<>(32-n)));
}
@@ -38,7 +47,7 @@ uint32_t rotr32(uint32_t a, uint8_t n){
#define X2 (((uint32_t*)b)[2])
#define X3 (((uint32_t*)b)[3])
-static void lt(uint8_t *b){
+static void serpent_lt(uint8_t *b){
X0 = rotl32(X0, 13);
X2 = rotl32(X2, 3);
X1 ^= X0 ^ X2;
@@ -51,7 +60,7 @@ static void lt(uint8_t *b){
X2 = rotr32(X2, 10);
}
-static void inv_lt(uint8_t *b){
+static void serpent_inv_lt(uint8_t *b){
X2 = rotl32(X2, 10);
X0 = rotr32(X0, 5);
X2 ^= X3 ^ (X1 << 7);
@@ -66,29 +75,28 @@ static void inv_lt(uint8_t *b){
#define GOLDEN_RATIO 0x9e3779b9l
-static uint32_t gen_w(uint32_t * b, uint8_t i){
+static uint32_t serpent_gen_w(uint32_t * b, uint8_t i){
uint32_t ret;
ret = b[0] ^ b[3] ^ b[5] ^ b[7] ^ GOLDEN_RATIO ^ (uint32_t)i;
ret = rotl32(ret, 11);
return ret;
}
-/* 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_b, serpent_ctx_t* ctx){
uint32_t buffer[8];
uint8_t i,j;
- if(keysize){
+ if(keysize_b<256){
/* keysize is less than 256 bit, padding needed */
memset(buffer, 0, 32);
- memcpy(buffer, key, (keysize+7)/8);
- ((uint8_t*)buffer)[keysize/8] |= 1<<(keysize%8);
+ memcpy(buffer, key, (keysize_b+7)/8);
+ ((uint8_t*)buffer)[keysize_b/8] |= 1<<(keysize_b%8);
} else {
/* keysize is 256 bit */
memcpy(buffer, key, 32);
}
for(i=0; i<33; ++i){
for(j=0; j<4; ++j){
- ctx->k[i][j] = gen_w(buffer, i*4+j);
+ ctx->k[i][j] = serpent_gen_w(buffer, i*4+j);
memmove(buffer, &(buffer[1]), 7*4); /* shift buffer one to the "left" */
buffer[7] = ctx->k[i][j];
}
@@ -98,32 +106,31 @@ void serpent_genctx(void * key, uint8_t keysize, serpent_ctx_t * ctx){
}
}
-
-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);
+ serpent_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);
+ serpent_inv_lt(buffer);
inv_sbox128(buffer, i);
- memxor((uint8_t*)buffer, ctx->k[i], 16);
+ memxor(buffer, ctx->k[i], 16);
}
}
@@ -131,4 +138,3 @@ void serpent_dec(void* buffer, serpent_ctx_t * ctx){
-