+/* 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 <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"
-
-uint8_t sbox[] PROGMEM = {
- 0x38, 0xF1, 0xA6, 0x5B, 0xED, 0x42, 0x70, 0x9C,
- 0xFC, 0x27, 0x90, 0x5A, 0x1B, 0xE8, 0x6D, 0x34,
- 0x86, 0x79, 0x3C, 0xAF, 0xD1, 0xE4, 0x0B, 0x52,
- 0x0F, 0xB8, 0xC9, 0x63, 0xD1, 0x24, 0xA7, 0x5E,
- 0x1F, 0x83, 0xC0, 0xB6, 0x25, 0x4A, 0x9E, 0x7D,
- 0xF5, 0x2B, 0x4A, 0x9C, 0x03, 0xE8, 0xD6, 0x71,
- 0x72, 0xC5, 0x84, 0x6B, 0xE9, 0x1F, 0xD3, 0xA0,
- 0x1D, 0xF0, 0xE8, 0x2B, 0x74, 0xCA, 0x93, 0x56,
-/* now the inverted sboxes */
- 0xD3, 0xB0, 0xA6, 0x5C, 0x1E, 0x47, 0xF9, 0x82,
- 0x58, 0x2E, 0xF6, 0xC3, 0xB4, 0x79, 0x1D, 0xA0,
- 0xC9, 0xF4, 0xBE, 0x12, 0x03, 0x6D, 0x58, 0xA7,
- 0x09, 0xA7, 0xBE, 0x6D, 0x35, 0xC2, 0x48, 0xF1,
- 0x50, 0x83, 0xA9, 0x7E, 0x2C, 0xB6, 0x4F, 0xD1,
- 0x8F, 0x29, 0x41, 0xDE, 0xB6, 0x53, 0x7C, 0xA0,
- 0xFA, 0x1D, 0x53, 0x60, 0x49, 0xE7, 0x2C, 0x8B,
- 0x30, 0x6D, 0x9E, 0xF8, 0x5C, 0xB7, 0xA1, 0x42
-};
-
-
-#define SHR_O(a) c=(a)&1; ((a) = (a)>>1)
-#define SHR_I(a) ((a) = (c?0x80:0x00)| ((a)>>1))
-
-static void ip(uint8_t *o, uint32_t *i){
- uint8_t c; // carry
- uint8_t n,m;
- memset(o, 0, 16);
- for(n=0; n<16; ++n){
- for(m=0; m<2; ++m){
- SHR_O(i[0]);
- SHR_I(o[n]);
- SHR_O(i[1]);
- SHR_I(o[n]);
- SHR_O(i[2]);
- SHR_I(o[n]);
- SHR_O(i[3]);
- SHR_I(o[n]);
- }
- }
-}
-
-#undef SHR_I
-#define SHR_I(a) ((a) = (c?0x80000000L:0x00L)| ((a)>>1)) /* we use 32-bit words here */
-
-
-static void fp(uint32_t *o, uint32_t *i){
- uint8_t c; // carry
- uint8_t n,m;
- memset(o, 0, 16);
- for(n=0; n<4; ++n){
- for(m=0; m<8; ++m){
- SHR_O(i[n]);
- SHR_I(o[0]);
- SHR_O(i[n]);
- SHR_I(o[1]);
- SHR_O(i[n]);
- SHR_I(o[2]);
- SHR_O(i[n]);
- SHR_I(o[3]);
- }
- }
-}
-
-/******************************************************************************/
-
-static void sbox128x(uint8_t box, void* w){
- uint8_t sb[16];
- uint8_t i,t,x;
- box &= 0x0f;
- /* load sbox */
- for(i=0; i<8; ++i){
- t = pgm_read_byte(sbox + box*8 + i);
- sb[2*i+0]=t>>4;
- sb[2*i+1]=t&0xf;
- }
- uint8_t o[16];
- ip(o, w);
-
- for(i=0; i<16; ++i){
- t = ((uint8_t*)o)[i];
- x = sb[t>>4];
- x <<= 4;
- x |= sb[t&0xf];
- ((uint8_t*)o)[i] = x;
- }
- fp(w, (uint32_t*)o);
-}
-
-static void sbox128(void * w, uint8_t box){
- sbox128x(box&0x7, w);
-}
-
-static void inv_sbox128(void * w, uint8_t box){
- sbox128x(((box&0x7)|0x8), w);
-}
-
-/******************************************************************************/
-
-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;
- }
-}
+#include "serpent-sboxes.h"
/******************************************************************************/
#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;
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);
#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];
}
}
}
-
-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);
}
}
-
projects / avr-crypto-lib.git / blobdiff