// serpent.cpp - written and placed in the public domain by Wei Dai

#include "pch.h"
#include "serpent.h"
#include "misc.h"

NAMESPACE_BEGIN(CryptoPP)

// linear transformation
#define LT(i,a,b,c,d,e)	{\
	a = rotlFixed(a, 13);	\
	c = rotlFixed(c, 3); 	\
	d = rotlFixed(d ^ c ^ (a << 3), 7); 	\
	b = rotlFixed(b ^ a ^ c, 1); 	\
	a = rotlFixed(a ^ b ^ d, 5); 		\
	c = rotlFixed(c ^ d ^ (b << 7), 22);}

// inverse linear transformation
#define ILT(i,a,b,c,d,e)	{\
	c = rotrFixed(c, 22);	\
	a = rotrFixed(a, 5); 	\
	c ^= d ^ (b << 7);	\
	a ^= b ^ d; 		\
	b = rotrFixed(b, 1); 	\
	d = rotrFixed(d, 7) ^ c ^ (a << 3);	\
	b ^= a ^ c; 		\
	c = rotrFixed(c, 3); 	\
	a = rotrFixed(a, 13);}

// order of output from S-box functions
#define beforeS0(f) f(0,a,b,c,d,e)
#define afterS0(f) f(1,b,e,c,a,d)
#define afterS1(f) f(2,c,b,a,e,d)
#define afterS2(f) f(3,a,e,b,d,c)
#define afterS3(f) f(4,e,b,d,c,a)
#define afterS4(f) f(5,b,a,e,c,d)
#define afterS5(f) f(6,a,c,b,e,d)
#define afterS6(f) f(7,a,c,d,b,e)
#define afterS7(f) f(8,d,e,b,a,c)

// order of output from inverse S-box functions
#define beforeI7(f) f(8,a,b,c,d,e)
#define afterI7(f) f(7,d,a,b,e,c)
#define afterI6(f) f(6,a,b,c,e,d)
#define afterI5(f) f(5,b,d,e,c,a)
#define afterI4(f) f(4,b,c,e,a,d)
#define afterI3(f) f(3,a,b,e,c,d)
#define afterI2(f) f(2,b,d,e,c,a)
#define afterI1(f) f(1,a,b,c,e,d)
#define afterI0(f) f(0,a,d,b,e,c)

// The instruction sequences for the S-box functions 
// come from Dag Arne Osvik's paper "Speeding up Serpent".

#define S0(i, r0, r1, r2, r3, r4) \
       {           \
    r3 ^= r0;   \
    r4 = r1;   \
    r1 &= r3;   \
    r4 ^= r2;   \
    r1 ^= r0;   \
    r0 |= r3;   \
    r0 ^= r4;   \
    r4 ^= r3;   \
    r3 ^= r2;   \
    r2 |= r1;   \
    r2 ^= r4;   \
    r4 = ~r4;      \
    r4 |= r1;   \
    r1 ^= r3;   \
    r1 ^= r4;   \
    r3 |= r0;   \
    r1 ^= r3;   \
    r4 ^= r3;   \
            }

#define I0(i, r0, r1, r2, r3, r4) \
       {           \
    r2 = ~r2;      \
    r4 = r1;   \
    r1 |= r0;   \
    r4 = ~r4;      \
    r1 ^= r2;   \
    r2 |= r4;   \
    r1 ^= r3;   \
    r0 ^= r4;   \
    r2 ^= r0;   \
    r0 &= r3;   \
    r4 ^= r0;   \
    r0 |= r1;   \
    r0 ^= r2;   \
    r3 ^= r4;   \
    r2 ^= r1;   \
    r3 ^= r0;   \
    r3 ^= r1;   \
    r2 &= r3;   \
    r4 ^= r2;   \
            }

#define S1(i, r0, r1, r2, r3, r4) \
       {           \
    r0 = ~r0;      \
    r2 = ~r2;      \
    r4 = r0;   \
    r0 &= r1;   \
    r2 ^= r0;   \
    r0 |= r3;   \
    r3 ^= r2;   \
    r1 ^= r0;   \
    r0 ^= r4;   \
    r4 |= r1;   \
    r1 ^= r3;   \
    r2 |= r0;   \
    r2 &= r4;   \
    r0 ^= r1;   \
    r1 &= r2;   \
    r1 ^= r0;   \
    r0 &= r2;   \
    r0 ^= r4;   \
            }

#define I1(i, r0, r1, r2, r3, r4) \
       {           \
    r4 = r1;   \
    r1 ^= r3;   \
    r3 &= r1;   \
    r4 ^= r2;   \
    r3 ^= r0;   \
    r0 |= r1;   \
    r2 ^= r3;   \
    r0 ^= r4;   \
    r0 |= r2;   \
    r1 ^= r3;   \
    r0 ^= r1;   \
    r1 |= r3;   \
    r1 ^= r0;   \
    r4 = ~r4;      \
    r4 ^= r1;   \
    r1 |= r0;   \
    r1 ^= r0;   \
    r1 |= r4;   \
    r3 ^= r1;   \
            }

#define S2(i, r0, r1, r2, r3, r4) \
       {           \
    r4 = r0;   \
    r0 &= r2;   \
    r0 ^= r3;   \
    r2 ^= r1;   \
    r2 ^= r0;   \
    r3 |= r4;   \
    r3 ^= r1;   \
    r4 ^= r2;   \
    r1 = r3;   \
    r3 |= r4;   \
    r3 ^= r0;   \
    r0 &= r1;   \
    r4 ^= r0;   \
    r1 ^= r3;   \
    r1 ^= r4;   \
    r4 = ~r4;      \
            }

#define I2(i, r0, r1, r2, r3, r4) \
       {           \
    r2 ^= r3;   \
    r3 ^= r0;   \
    r4 = r3;   \
    r3 &= r2;   \
    r3 ^= r1;   \
    r1 |= r2;   \
    r1 ^= r4;   \
    r4 &= r3;   \
    r2 ^= r3;   \
    r4 &= r0;   \
    r4 ^= r2;   \
    r2 &= r1;   \
    r2 |= r0;   \
    r3 = ~r3;      \
    r2 ^= r3;   \
    r0 ^= r3;   \
    r0 &= r1;   \
    r3 ^= r4;   \
    r3 ^= r0;   \
            }

#define S3(i, r0, r1, r2, r3, r4) \
       {           \
    r4 = r0;   \
    r0 |= r3;   \
    r3 ^= r1;   \
    r1 &= r4;   \
    r4 ^= r2;   \
    r2 ^= r3;   \
    r3 &= r0;   \
    r4 |= r1;   \
    r3 ^= r4;   \
    r0 ^= r1;   \
    r4 &= r0;   \
    r1 ^= r3;   \
    r4 ^= r2;   \
    r1 |= r0;   \
    r1 ^= r2;   \
    r0 ^= r3;   \
    r2 = r1;   \
    r1 |= r3;   \
    r1 ^= r0;   \
            }

#define I3(i, r0, r1, r2, r3, r4) \
       {           \
    r4 = r2;   \
    r2 ^= r1;   \
    r1 &= r2;   \
    r1 ^= r0;   \
    r0 &= r4;   \
    r4 ^= r3;   \
    r3 |= r1;   \
    r3 ^= r2;   \
    r0 ^= r4;   \
    r2 ^= r0;   \
    r0 |= r3;   \
    r0 ^= r1;   \
    r4 ^= r2;   \
    r2 &= r3;   \
    r1 |= r3;   \
    r1 ^= r2;   \
    r4 ^= r0;   \
    r2 ^= r4;   \
            }

#define S4(i, r0, r1, r2, r3, r4) \
       {           \
    r1 ^= r3;   \
    r3 = ~r3;      \
    r2 ^= r3;   \
    r3 ^= r0;   \
    r4 = r1;   \
    r1 &= r3;   \
    r1 ^= r2;   \
    r4 ^= r3;   \
    r0 ^= r4;   \
    r2 &= r4;   \
    r2 ^= r0;   \
    r0 &= r1;   \
    r3 ^= r0;   \
    r4 |= r1;   \
    r4 ^= r0;   \
    r0 |= r3;   \
    r0 ^= r2;   \
    r2 &= r3;   \
    r0 = ~r0;      \
    r4 ^= r2;   \
            }

#define I4(i, r0, r1, r2, r3, r4) \
       {           \
    r4 = r2;   \
    r2 &= r3;   \
    r2 ^= r1;   \
    r1 |= r3;   \
    r1 &= r0;   \
    r4 ^= r2;   \
    r4 ^= r1;   \
    r1 &= r2;   \
    r0 = ~r0;      \
    r3 ^= r4;   \
    r1 ^= r3;   \
    r3 &= r0;   \
    r3 ^= r2;   \
    r0 ^= r1;   \
    r2 &= r0;   \
    r3 ^= r0;   \
    r2 ^= r4;   \
    r2 |= r3;   \
    r3 ^= r0;   \
    r2 ^= r1;   \
            }

#define S5(i, r0, r1, r2, r3, r4) \
       {           \
    r0 ^= r1;   \
    r1 ^= r3;   \
    r3 = ~r3;      \
    r4 = r1;   \
    r1 &= r0;   \
    r2 ^= r3;   \
    r1 ^= r2;   \
    r2 |= r4;   \
    r4 ^= r3;   \
    r3 &= r1;   \
    r3 ^= r0;   \
    r4 ^= r1;   \
    r4 ^= r2;   \
    r2 ^= r0;   \
    r0 &= r3;   \
    r2 = ~r2;      \
    r0 ^= r4;   \
    r4 |= r3;   \
    r2 ^= r4;   \
            }

#define I5(i, r0, r1, r2, r3, r4) \
       {           \
    r1 = ~r1;      \
    r4 = r3;   \
    r2 ^= r1;   \
    r3 |= r0;   \
    r3 ^= r2;   \
    r2 |= r1;   \
    r2 &= r0;   \
    r4 ^= r3;   \
    r2 ^= r4;   \
    r4 |= r0;   \
    r4 ^= r1;   \
    r1 &= r2;   \
    r1 ^= r3;   \
    r4 ^= r2;   \
    r3 &= r4;   \
    r4 ^= r1;   \
    r3 ^= r0;   \
    r3 ^= r4;   \
    r4 = ~r4;      \
            }

#define S6(i, r0, r1, r2, r3, r4) \
       {           \
    r2 = ~r2;      \
    r4 = r3;   \
    r3 &= r0;   \
    r0 ^= r4;   \
    r3 ^= r2;   \
    r2 |= r4;   \
    r1 ^= r3;   \
    r2 ^= r0;   \
    r0 |= r1;   \
    r2 ^= r1;   \
    r4 ^= r0;   \
    r0 |= r3;   \
    r0 ^= r2;   \
    r4 ^= r3;   \
    r4 ^= r0;   \
    r3 = ~r3;      \
    r2 &= r4;   \
    r2 ^= r3;   \
            }

#define I6(i, r0, r1, r2, r3, r4) \
       {           \
    r0 ^= r2;   \
    r4 = r2;   \
    r2 &= r0;   \
    r4 ^= r3;   \
    r2 = ~r2;      \
    r3 ^= r1;   \
    r2 ^= r3;   \
    r4 |= r0;   \
    r0 ^= r2;   \
    r3 ^= r4;   \
    r4 ^= r1;   \
    r1 &= r3;   \
    r1 ^= r0;   \
    r0 ^= r3;   \
    r0 |= r2;   \
    r3 ^= r1;   \
    r4 ^= r0;   \
            }

#define S7(i, r0, r1, r2, r3, r4) \
       {           \
    r4 = r2;   \
    r2 &= r1;   \
    r2 ^= r3;   \
    r3 &= r1;   \
    r4 ^= r2;   \
    r2 ^= r1;   \
    r1 ^= r0;   \
    r0 |= r4;   \
    r0 ^= r2;   \
    r3 ^= r1;   \
    r2 ^= r3;   \
    r3 &= r0;   \
    r3 ^= r4;   \
    r4 ^= r2;   \
    r2 &= r0;   \
    r4 = ~r4;      \
    r2 ^= r4;   \
    r4 &= r0;   \
    r1 ^= r3;   \
    r4 ^= r1;   \
            }

#define I7(i, r0, r1, r2, r3, r4) \
       {           \
    r4 = r2;   \
    r2 ^= r0;   \
    r0 &= r3;   \
    r2 = ~r2;      \
    r4 |= r3;   \
    r3 ^= r1;   \
    r1 |= r0;   \
    r0 ^= r2;   \
    r2 &= r4;   \
    r1 ^= r2;   \
    r2 ^= r0;   \
    r0 |= r2;   \
    r3 &= r4;   \
    r0 ^= r3;   \
    r4 ^= r1;   \
    r3 ^= r4;   \
    r4 |= r0;   \
    r3 ^= r2;   \
    r4 ^= r2;   \
            }

// key xor
#define KX(r, a, b, c, d, e)	{\
	a ^= k[4 * r + 0]; \
	b ^= k[4 * r + 1]; \
	c ^= k[4 * r + 2]; \
	d ^= k[4 * r + 3];}

void Serpent::Base::UncheckedSetKey(CipherDir direction, const byte *userKey, unsigned int keylen)
{
	AssertValidKeyLength(keylen);

	word32 *k = m_key;
	GetUserKey(LITTLE_ENDIAN_ORDER, k, 8, userKey, keylen);

	if (keylen < 32)
		k[keylen/4] |= word32(1) << ((keylen%4)*8);

	k += 8;
	word32 t = k[-1];
	signed int i;
	for (i = 0; i < 132; ++i)
		k[i] = t = rotlFixed(k[i-8] ^ k[i-5] ^ k[i-3] ^ t ^ 0x9e3779b9 ^ i, 11);
	k -= 20;

#define LK(r, a, b, c, d, e)	{\
	a = k[(8-r)*4 + 0];		\
	b = k[(8-r)*4 + 1];		\
	c = k[(8-r)*4 + 2];		\
	d = k[(8-r)*4 + 3];}

#define SK(r, a, b, c, d, e)	{\
	k[(8-r)*4 + 4] = a;		\
	k[(8-r)*4 + 5] = b;		\
	k[(8-r)*4 + 6] = c;		\
	k[(8-r)*4 + 7] = d;}	\

	word32 a,b,c,d,e;
	for (i=0; i<4; i++)
	{
		afterS2(LK); afterS2(S3); afterS3(SK);
		afterS1(LK); afterS1(S2); afterS2(SK);
		afterS0(LK); afterS0(S1); afterS1(SK);
		beforeS0(LK); beforeS0(S0); afterS0(SK);
		k += 8*4;
		afterS6(LK); afterS6(S7); afterS7(SK);
		afterS5(LK); afterS5(S6); afterS6(SK);
		afterS4(LK); afterS4(S5); afterS5(SK);
		afterS3(LK); afterS3(S4); afterS4(SK);
	}
	afterS2(LK); afterS2(S3); afterS3(SK);
}

typedef BlockGetAndPut<word32, LittleEndian> Block;

void Serpent::Enc::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 + 8;
	unsigned int i=1;

	do
	{
		beforeS0(KX); beforeS0(S0); afterS0(LT);
		afterS0(KX); afterS0(S1); afterS1(LT);
		afterS1(KX); afterS1(S2); afterS2(LT);
		afterS2(KX); afterS2(S3); afterS3(LT);
		afterS3(KX); afterS3(S4); afterS4(LT);
		afterS4(KX); afterS4(S5); afterS5(LT);
		afterS5(KX); afterS5(S6); afterS6(LT);
		afterS6(KX); afterS6(S7);

		if (i == 4)
			break;

		++i;
		c = b;
		b = e;
		e = d;
		d = a;
		a = e;
		k += 32;
		beforeS0(LT);
	}
	while (true);

	afterS7(KX);
	
	Block::Put(xorBlock, outBlock)(d)(e)(b)(a);
}

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 + 104;
	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);
}

NAMESPACE_END