// 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 ¶ms)
{
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
