X-Git-Url: https://git.cryptolib.org/?a=blobdiff_plain;f=serpent.c;h=6506b2ad2b70495db93c40054bbf997ecf1bf2d3;hb=17332291e15183d71d88ed868275e3cb53917180;hp=85cf4a852e4a731d46fc63e3baf852deeb5acd05;hpb=6725841b72687bd3ede509c41ac50746c6bd1828;p=avr-crypto-lib.git diff --git a/serpent.c b/serpent.c index 85cf4a8..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 @@ -8,114 +26,9 @@ #include #include /* memset() */ #include +#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" /******************************************************************************/ @@ -134,7 +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; @@ -147,7 +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); @@ -162,29 +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]; } @@ -194,32 +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); } } @@ -227,4 +138,3 @@ void serpent_dec(void* buffer, serpent_ctx_t * ctx){ -