void Serpent::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
{
word32 a, b, c, d, e;
Block::Get(inBlock)(a)(b)(c)(d);
const word32 *k = m_key + 96;
unsigned int i=4;
beforeI7(KX);
goto start;
do
{
c = b;
b = d;
d = e;
k -= 32;
beforeI7(ILT);
start:
beforeI7(I7); afterI7(KX);
afterI7(ILT); afterI7(I6); afterI6(KX);
afterI6(ILT); afterI6(I5); afterI5(KX);
afterI5(ILT); afterI5(I4); afterI4(KX);
afterI4(ILT); afterI4(I3); afterI3(KX);
afterI3(ILT); afterI3(I2); afterI2(KX);
afterI2(ILT); afterI2(I1); afterI1(KX);
afterI1(ILT); afterI1(I0); afterI0(KX);
}
while (--i != 0);
Block::Put(xorBlock, outBlock)(a)(d)(b)(e);
}
void serpent_decrypt_block(block128_t* block, uint32_t* subkey) {
//char* function_name = "serpent_decrypt_block()";
uint32_t a, b, c, d, e;
int j;
// Change to little endian.
a = mirror_bytes32(block->x0);
b = mirror_bytes32(block->x1);
c = mirror_bytes32(block->x2);
d = mirror_bytes32(block->x3);
// Decrypt the current block.
j = 4;
subkey += 96;
beforeI7(KX);
goto start;
do
{
c = b;
b = d;
d = e;
subkey -= 32;
beforeI7(inverse_linear_transformation);
start:
beforeI7(I7); afterI7(KX);
afterI7(inverse_linear_transformation); afterI7(I6); afterI6(KX);
afterI6(inverse_linear_transformation); afterI6(I5); afterI5(KX);
afterI5(inverse_linear_transformation); afterI5(I4); afterI4(KX);
afterI4(inverse_linear_transformation); afterI4(I3); afterI3(KX);
afterI3(inverse_linear_transformation); afterI3(I2); afterI2(KX);
afterI2(inverse_linear_transformation); afterI2(I1); afterI1(KX);
afterI1(inverse_linear_transformation); afterI1(I0); afterI0(KX);
}
while (--j != 0);
// Restore to big endian, taking into account the significance of each block.
block->x0 = mirror_bytes32(a);
block->x1 = mirror_bytes32(d);
block->x2 = mirror_bytes32(b);
block->x3 = mirror_bytes32(e);
}
void serpent_decrypt(const unsigned __int8 *inBlock, unsigned __int8 *outBlock, unsigned __int8 *ks)
{
unsigned __int32 a, b, c, d, e;
const unsigned __int32 *k = (unsigned __int32 *)ks + 104;
unsigned int i=4;
unsigned __int32 *in = (unsigned __int32 *) inBlock;
unsigned __int32 *out = (unsigned __int32 *) outBlock;
a = LE32(in[0]);
b = LE32(in[1]);
c = LE32(in[2]);
d = LE32(in[3]);
beforeI7(KX);
goto start;
do
{
c = b;
b = d;
d = e;
k -= 32;
beforeI7(ILT);
start:
beforeI7(I7); afterI7(KX);
afterI7(ILT); afterI7(I6); afterI6(KX);
afterI6(ILT); afterI6(I5); afterI5(KX);
afterI5(ILT); afterI5(I4); afterI4(KX);
afterI4(ILT); afterI4(I3); afterI3(KX);
afterI3(ILT); afterI3(I2); afterI2(KX);
afterI2(ILT); afterI2(I1); afterI1(KX);
afterI1(ILT); afterI1(I0); afterI0(KX);
}
while (--i != 0);
out[0] = LE32(a);
out[1] = LE32(d);
out[2] = LE32(b);
out[3] = LE32(e);
}