~zooko/cryptopp/trunk

// 3way.cpp - modifed by Wei Dai from Joan Daemen's 3way.c

// The original code and all modifications are in the public domain.

#include "pch.h"

#include "3way.h"

#include "misc.h"

NAMESPACE_BEGIN(CryptoPP)

void ThreeWay_TestInstantiations()

{

	ThreeWay::Encryption x1;

	ThreeWay::Decryption x2;

}

static const word32 START_E = 0x0b0b; // round constant of first encryption round

static const word32 START_D = 0xb1b1; // round constant of first decryption round

static const word32 RC_MODULUS = 0x11011;

static inline word32 reverseBits(word32 a)

{

	a = ((a & 0xAAAAAAAA) >> 1) | ((a & 0x55555555) << 1);

	a = ((a & 0xCCCCCCCC) >> 2) | ((a & 0x33333333) << 2);

	return ((a & 0xF0F0F0F0) >> 4) | ((a & 0x0F0F0F0F) << 4);

}

#define mu(a0, a1, a2)				\

{									\

	a1 = reverseBits(a1);			\

	word32 t = reverseBits(a0);		\

	a0 = reverseBits(a2);			\

	a2 = t;							\

}

#define pi_gamma_pi(a0, a1, a2)		\

{									\

	word32 b0, b2;					\

	b2 = rotlFixed(a2, 1U);				\

	b0 = rotlFixed(a0, 22U);				\

	a0 = rotlFixed(b0 ^ (a1|(~b2)), 1U);	\

	a2 = rotlFixed(b2 ^ (b0|(~a1)), 22U);\

	a1 ^= (b2|(~b0));				\

}

// thanks to Paulo Barreto for this optimized theta()

#define theta(a0, a1, a2)									\

{ 															\

	word32 b0, b1, c; 										\

	c = a0 ^ a1 ^ a2; 										\

	c = rotlFixed(c, 16U) ^ rotlFixed(c, 8U);				\

	b0 = (a0 << 24) ^ (a2 >> 8) ^ (a1 << 8) ^ (a0 >> 24); 	\

	b1 = (a1 << 24) ^ (a0 >> 8) ^ (a2 << 8) ^ (a1 >> 24); 	\

	a0 ^= c ^ b0; 											\

	a1 ^= c ^ b1; 											\

	a2 ^= c ^ (b0 >> 16) ^ (b1 << 16); 						\

}															

#define rho(a0, a1, a2)			\

{								\

	theta(a0, a1, a2);			\

	pi_gamma_pi(a0, a1, a2);	\

}											

void ThreeWay::Base::UncheckedSetKey(const byte *uk, unsigned int length, const NameValuePairs &params)

{

	AssertValidKeyLength(length);

	m_rounds = GetRoundsAndThrowIfInvalid(params, this);

	for (unsigned int i=0; i<3; i++)

		m_k[i] = (word32)uk[4*i+3] | ((word32)uk[4*i+2]<<8) | ((word32)uk[4*i+1]<<16) | ((word32)uk[4*i]<<24);

	if (!IsForwardTransformation())

	{

		theta(m_k[0], m_k[1], m_k[2]);

		mu(m_k[0], m_k[1], m_k[2]);

		m_k[0] = ByteReverse(m_k[0]);

		m_k[1] = ByteReverse(m_k[1]);

		m_k[2] = ByteReverse(m_k[2]);

	}

}

void ThreeWay::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const

{

	typedef BlockGetAndPut<word32, BigEndian> Block;

	word32 a0, a1, a2;

	Block::Get(inBlock)(a0)(a1)(a2);

	word32 rc = START_E;

	for(unsigned i=0; i<m_rounds; i++)

	{

		a0 ^= m_k[0] ^ (rc<<16);

		a1 ^= m_k[1];

		a2 ^= m_k[2] ^ rc;

		rho(a0, a1, a2);

		rc <<= 1;

		if (rc&0x10000) rc ^= 0x11011;

	}

	a0 ^= m_k[0] ^ (rc<<16);

	a1 ^= m_k[1];

	a2 ^= m_k[2] ^ rc;

	theta(a0, a1, a2);

	Block::Put(xorBlock, outBlock)(a0)(a1)(a2);

}

void ThreeWay::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const

{

	typedef BlockGetAndPut<word32, LittleEndian> Block;

	word32 a0, a1, a2;

	Block::Get(inBlock)(a0)(a1)(a2);

	word32 rc = START_D;

	mu(a0, a1, a2);

	for(unsigned i=0; i<m_rounds; i++)

	{

		a0 ^= m_k[0] ^ (rc<<16);

		a1 ^= m_k[1];

		a2 ^= m_k[2] ^ rc;

		rho(a0, a1, a2);

		rc <<= 1;

		if (rc&0x10000) rc ^= 0x11011;

	}

	a0 ^= m_k[0] ^ (rc<<16);

	a1 ^= m_k[1];

	a2 ^= m_k[2] ^ rc;

	theta(a0, a1, a2);

	mu(a0, a1, a2);

	Block::Put(xorBlock, outBlock)(a0)(a1)(a2);

}

NAMESPACE_END