/* twofish.cpp                                 * * Copyright (C) 2003 Sawtooth Consulting Ltd. * * This file is part of yaSSL. * * yaSSL 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 2 of the License, or * (at your option) any later version. * * yaSSL 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, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA *//* C++ based on Wei Dai's twofish.cpp from CryptoPP *//* x86 asm original */#if defined(TAOCRYPT_KERNEL_MODE)    #define DO_TAOCRYPT_KERNEL_MODE#endif                                  // only some modules now support this#include "runtime.hpp"#include "twofish.hpp"#if defined(TAOCRYPT_X86ASM_AVAILABLE) && defined(TAO_ASM)    #define DO_TWOFISH_ASM#endifnamespace TaoCrypt {#if !defined(DO_TWOFISH_ASM)// Generic Versionvoid Twofish::Process(byte* out, const byte* in, word32 sz){    if (mode_ == ECB)        ECB_Process(out, in, sz);    else if (mode_ == CBC)        if (dir_ == ENCRYPTION)            CBC_Encrypt(out, in, sz);        else            CBC_Decrypt(out, in, sz);}#else// ia32 optimized versionvoid Twofish::Process(byte* out, const byte* in, word32 sz){    word32 blocks = sz / BLOCK_SIZE;    if (mode_ == ECB)        while (blocks--) {            if (dir_ == ENCRYPTION)                AsmEncrypt(in, out);            else                AsmDecrypt(in, out);                    out += BLOCK_SIZE;            in  += BLOCK_SIZE;        }    else if (mode_ == CBC)        if (dir_ == ENCRYPTION)            while (blocks--) {                r_[0] ^= *(word32*)in;                r_[1] ^= *(word32*)(in +  4);                r_[2] ^= *(word32*)(in +  8);                r_[3] ^= *(word32*)(in + 12);                AsmEncrypt((byte*)r_, (byte*)r_);                memcpy(out, r_, BLOCK_SIZE);                out += BLOCK_SIZE;                in  += BLOCK_SIZE;            }        else            while (blocks--) {                AsmDecrypt(in, out);                               *(word32*)out        ^= r_[0];                *(word32*)(out +  4) ^= r_[1];                *(word32*)(out +  8) ^= r_[2];                *(word32*)(out + 12) ^= r_[3];                memcpy(r_, in, BLOCK_SIZE);                out += BLOCK_SIZE;                in  += BLOCK_SIZE;            }}#endif // DO_TWOFISH_ASMnamespace {     // locals// compute (c * x^4) mod (x^4 + (a + 1/a) * x^3 + a * x^2 + (a + 1/a) * x + 1)// over GF(256)static inline unsigned int Mod(unsigned int c){	static const unsigned int modulus = 0x14d;	unsigned int c2 = (c<<1) ^ ((c & 0x80) ? modulus : 0);	unsigned int c1 = c2 ^ (c>>1) ^ ((c & 1) ? (modulus>>1) : 0);	return c | (c1 << 8) | (c2 << 16) | (c1 << 24);}// compute RS(12,8) code with the above polynomial as generator// this is equivalent to multiplying by the RS matrixstatic word32 ReedSolomon(word32 high, word32 low){	for (unsigned int i=0; i<8; i++) {		high = Mod(high>>24) ^ (high<<8) ^ (low>>24);		low <<= 8;	}	return high;}}  // local namespaceinline word32 Twofish::h0(word32 x, const word32* key, unsigned int kLen){	x = x | (x<<8) | (x<<16) | (x<<24);	switch(kLen)	{#define Q(a, b, c, d, t) q_[a][GETBYTE(t,0)] ^ (q_[b][GETBYTE(t,1)] << 8) ^  \            (q_[c][GETBYTE(t,2)] << 16) ^ (q_[d][GETBYTE(t,3)] << 24)	case 4: x = Q(1, 0, 0, 1, x) ^ key[6];	case 3: x = Q(1, 1, 0, 0, x) ^ key[4];	case 2: x = Q(0, 1, 0, 1, x) ^ key[2];			x = Q(0, 0, 1, 1, x) ^ key[0];	}	return x;}inline word32 Twofish::h(word32 x, const word32* key, unsigned int kLen){	x = h0(x, key, kLen);	return mds_[0][GETBYTE(x,0)] ^ mds_[1][GETBYTE(x,1)] ^         mds_[2][GETBYTE(x,2)] ^ mds_[3][GETBYTE(x,3)];}void Twofish::SetKey(const byte* userKey, word32 keylen, CipherDir /*dummy*/){	assert(keylen >= 16 && keylen <= 32);	unsigned int len = (keylen <= 16 ? 2 : (keylen <= 24 ? 3 : 4));    word32 key[8];	GetUserKey(LittleEndianOrder, key, len*2, userKey, keylen);	unsigned int i;	for (i=0; i<40; i+=2) {		word32 a = h(i, key, len);		word32 b = rotlFixed(h(i+1, key+1, len), 8);		k_[i] = a+b;		k_[i+1] = rotlFixed(a+2*b, 9);	}	word32 svec[8];	for (i=0; i<len; i++)		svec[2*(len-i-1)] = ReedSolomon(key[2*i+1], key[2*i]);	for (i=0; i<256; i++) {		word32 t = h0(i, svec, len);		s_[0][i] = mds_[0][GETBYTE(t, 0)];		s_[1][i] = mds_[1][GETBYTE(t, 1)];		s_[2][i] = mds_[2][GETBYTE(t, 2)];		s_[3][i] = mds_[3][GETBYTE(t, 3)];	}}void Twofish::ProcessAndXorBlock(const byte* in, const byte* xOr, byte* out)    const{    if (dir_ == ENCRYPTION)        encrypt(in, xOr, out);    else        decrypt(in, xOr, out);}#define G1(x) (s_[0][GETBYTE(x,0)] ^ s_[1][GETBYTE(x,1)] ^ \            s_[2][GETBYTE(x,2)] ^ s_[3][GETBYTE(x,3)])#define G2(x) (s_[0][GETBYTE(x,3)] ^ s_[1][GETBYTE(x,0)] ^ \            s_[2][GETBYTE(x,1)] ^ s_[3][GETBYTE(x,2)])#define ENCROUND(n, a, b, c, d) \	x = G1 (a); y = G2 (b); \	x += y; y += x + k[2 * (n) + 1]; \	(c) ^= x + k[2 * (n)]; \	(c) = rotrFixed(c, 1); \	(d) = rotlFixed(d, 1) ^ y#define ENCCYCLE(n) \	ENCROUND (2 * (n), a, b, c, d); \	ENCROUND (2 * (n) + 1, c, d, a, b)#define DECROUND(n, a, b, c, d) \	x = G1 (a); y = G2 (b); \	x += y; y += x; \	(d) ^= y + k[2 * (n) + 1]; \	(d) = rotrFixed(d, 1); \	(c) = rotlFixed(c, 1); \	(c) ^= (x + k[2 * (n)])#define DECCYCLE(n) \	DECROUND (2 * (n) + 1, c, d, a, b); \	DECROUND (2 * (n), a, b, c, d)typedef BlockGetAndPut<word32, LittleEndian> gpBlock;void Twofish::encrypt(const byte* inBlock, const byte* xorBlock,                  byte* outBlock) const{	word32 x, y, a, b, c, d;	gpBlock::Get(inBlock)(a)(b)(c)(d);	a ^= k_[0];	b ^= k_[1];	c ^= k_[2];	d ^= k_[3];	const word32 *k = k_+8;	ENCCYCLE (0);	ENCCYCLE (1);	ENCCYCLE (2);	ENCCYCLE (3);	ENCCYCLE (4);	ENCCYCLE (5);	ENCCYCLE (6);	ENCCYCLE (7);	c ^= k_[4];	d ^= k_[5];	a ^= k_[6];	b ^= k_[7]; 	gpBlock::Put(xorBlock, outBlock)(c)(d)(a)(b);}void Twofish::decrypt(const byte* inBlock, const byte* xorBlock,                  byte* outBlock) const{	word32 x, y, a, b, c, d;	gpBlock::Get(inBlock)(c)(d)(a)(b);	c ^= k_[4];	d ^= k_[5];	a ^= k_[6];	b ^= k_[7];	const word32 *k = k_+8;	DECCYCLE (7);	DECCYCLE (6);	DECCYCLE (5);	DECCYCLE (4);	DECCYCLE (3);	DECCYCLE (2);	DECCYCLE (1);	DECCYCLE (0);	a ^= k_[0];	b ^= k_[1];	c ^= k_[2];	d ^= k_[3];	gpBlock::Put(xorBlock, outBlock)(a)(b)(c)(d);}#if defined(DO_TWOFISH_ASM)    #ifdef __GNUC__        #define AS1(x)    asm(#x);        #define AS2(x, y) asm(#x ", " #y);        #define PROLOG()  \            asm(".intel_syntax noprefix"); \