/*************************************************
* Serpent Source File                            *
* (C) 1999-2006 The Botan Project                *
*************************************************/

#include <botan/serpent.h>
#include <botan/bit_ops.h>

namespace Botan {

namespace {

/*************************************************
* Serpent Encryption S-Box 1                     *
*************************************************/
inline void SBoxE1(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   u32bit T0 = B0, T1 = B1, T2 = B2, T3 = B3, T4;
   T3 ^= T0; T4  = T1; T1 &= T3; T4 ^= T2; T1 ^= T0; T0 |= T3; T0 ^= T4;
   T4 ^= T3; T3 ^= T2; T2 |= T1; T2 ^= T4; T4 = ~T4; T4 |= T1; T1 ^= T3;
   T1 ^= T4; T3 |= T0; T1 ^= T3; T4 ^= T3;
   B0 = T1; B1 = T4; B2 = T2; B3 = T0;
   }

/*************************************************
* Serpent Encryption S-Box 2                     *
*************************************************/
inline void SBoxE2(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   u32bit T0 = B0, T1 = B1, T2 = B2, T3 = B3, T4;
   T0 = ~T0; T2 = ~T2; T4  = T0; T0 &= T1; T2 ^= T0; T0 |= T3; T3 ^= T2;
   T1 ^= T0; T0 ^= T4; T4 |= T1; T1 ^= T3; T2 |= T0; T2 &= T4; T0 ^= T1;
   T1 &= T2; T1 ^= T0; T0 &= T2; T0 ^= T4;
   B0 = T2; B1 = T0; B2 = T3; B3 = T1;
   }

/*************************************************
* Serpent Encryption S-Box 3                     *
*************************************************/
inline void SBoxE3(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   u32bit T0 = B0, T1 = B1, T2 = B2, T3 = B3, T4;
   T4  = T0; T0 &= T2; T0 ^= T3; T2 ^= T1; T2 ^= T0; T3 |= T4; T3 ^= T1;
   T4 ^= T2; T1  = T3; T3 |= T4; T3 ^= T0; T0 &= T1; T4 ^= T0; T1 ^= T3;
   T1 ^= T4; T4 = ~T4;
   B0 = T2; B1 = T3; B2 = T1; B3 = T4;
   }

/*************************************************
* Serpent Encryption S-Box 4                     *
*************************************************/
inline void SBoxE4(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   u32bit T0 = B0, T1 = B1, T2 = B2, T3 = B3, T4;
   T4  = T0; T0 |= T3; T3 ^= T1; T1 &= T4; T4 ^= T2; T2 ^= T3; T3 &= T0;
   T4 |= T1; T3 ^= T4; T0 ^= T1; T4 &= T0; T1 ^= T3; T4 ^= T2; T1 |= T0;
   T1 ^= T2; T0 ^= T3; T2  = T1; T1 |= T3; T1 ^= T0;
   B0 = T1; B1 = T2; B2 = T3; B3 = T4;
   }

/*************************************************
* Serpent Encryption S-Box 5                     *
*************************************************/
inline void SBoxE5(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   u32bit T0 = B0, T1 = B1, T2 = B2, T3 = B3, T4;
   T1 ^= T3; T3 = ~T3; T2 ^= T3; T3 ^= T0; T4  = T1; T1 &= T3; T1 ^= T2;
   T4 ^= T3; T0 ^= T4; T2 &= T4; T2 ^= T0; T0 &= T1; T3 ^= T0; T4 |= T1;
   T4 ^= T0; T0 |= T3; T0 ^= T2; T2 &= T3; T0 = ~T0; T4 ^= T2;
   B0 = T1; B1 = T4; B2 = T0; B3 = T3;
   }

/*************************************************
* Serpent Encryption S-Box 6                     *
*************************************************/
inline void SBoxE6(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   u32bit T0 = B0, T1 = B1, T2 = B2, T3 = B3, T4;
   T0 ^= T1; T1 ^= T3; T3 = ~T3; T4  = T1; T1 &= T0; T2 ^= T3; T1 ^= T2;
   T2 |= T4; T4 ^= T3; T3 &= T1; T3 ^= T0; T4 ^= T1; T4 ^= T2; T2 ^= T0;
   T0 &= T3; T2 = ~T2; T0 ^= T4; T4 |= T3; T2 ^= T4;
   B0 = T1; B1 = T3; B2 = T0; B3 = T2;
   }

/*************************************************
* Serpent Encryption S-Box 7                     *
*************************************************/
inline void SBoxE7(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   u32bit T0 = B0, T1 = B1, T2 = B2, T3 = B3, T4;
   T2 = ~T2; T4  = T3; T3 &= T0; T0 ^= T4; T3 ^= T2; T2 |= T4; T1 ^= T3;
   T2 ^= T0; T0 |= T1; T2 ^= T1; T4 ^= T0; T0 |= T3; T0 ^= T2; T4 ^= T3;
   T4 ^= T0; T3 = ~T3; T2 &= T4; T2 ^= T3;
   B0 = T0; B1 = T1; B2 = T4; B3 = T2;
   }

/*************************************************
* Serpent Encryption S-Box 8                     *
*************************************************/
inline void SBoxE8(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   u32bit T0 = B0, T1 = B1, T2 = B2, T3 = B3, T4;
   T4  = T1; T1 |= T2; T1 ^= T3; T4 ^= T2; T2 ^= T1; T3 |= T4; T3 &= T0;
   T4 ^= T2; T3 ^= T1; T1 |= T4; T1 ^= T0; T0 |= T4; T0 ^= T2; T1 ^= T4;
   T2 ^= T1; T1 &= T0; T1 ^= T4; T2 = ~T2; T2 |= T0; T4 ^= T2;
   B0 = T4; B1 = T3; B2 = T1; B3 = T0;
   }

/*************************************************
* Serpent Decryption S-Box 1                     *
*************************************************/
inline void SBoxD1(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   u32bit T0 = B0, T1 = B1, T2 = B2, T3 = B3, T4;
   T2 = ~T2; T4  = T1; T1 |= T0; T4 = ~T4; T1 ^= T2; T2 |= T4; T1 ^= T3;
   T0 ^= T4; T2 ^= T0; T0 &= T3; T4 ^= T0; T0 |= T1; T0 ^= T2; T3 ^= T4;
   T2 ^= T1; T3 ^= T0; T3 ^= T1; T2 &= T3; T4 ^= T2;
   B0 = T0; B1 = T4; B2 = T1; B3 = T3;
   }

/*************************************************
* Serpent Decryption S-Box 2                     *
*************************************************/
inline void SBoxD2(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   u32bit T0 = B0, T1 = B1, T2 = B2, T3 = B3, T4;
   T4  = T1; T1 ^= T3; T3 &= T1; T4 ^= T2; T3 ^= T0; T0 |= T1; T2 ^= T3;
   T0 ^= T4; T0 |= T2; T1 ^= T3; T0 ^= T1; T1 |= T3; T1 ^= T0; T4 = ~T4;
   T4 ^= T1; T1 |= T0; T1 ^= T0; T1 |= T4; T3 ^= T1;
   B0 = T4; B1 = T0; B2 = T3; B3 = T2;
   }

/*************************************************
* Serpent Decryption S-Box 3                     *
*************************************************/
inline void SBoxD3(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   u32bit T0 = B0, T1 = B1, T2 = B2, T3 = B3, T4;
   T2 ^= T3; T3 ^= T0; T4  = T3; T3 &= T2; T3 ^= T1; T1 |= T2; T1 ^= T4;
   T4 &= T3; T2 ^= T3; T4 &= T0; T4 ^= T2; T2 &= T1; T2 |= T0; T3 = ~T3;
   T2 ^= T3; T0 ^= T3; T0 &= T1; T3 ^= T4; T3 ^= T0;
   B0 = T1; B1 = T4; B2 = T2; B3 = T3;
   }

/*************************************************
* Serpent Decryption S-Box 4                     *
*************************************************/
inline void SBoxD4(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   u32bit T0 = B0, T1 = B1, T2 = B2, T3 = B3, T4;
   T4  = T2; T2 ^= T1; T0 ^= T2; T4 &= T2; T4 ^= T0; T0 &= T1; T1 ^= T3;
   T3 |= T4; T2 ^= T3; T0 ^= T3; T1 ^= T4; T3 &= T2; T3 ^= T1; T1 ^= T0;
   T1 |= T2; T0 ^= T3; T1 ^= T4; T0 ^= T1;
   B0 = T2; B1 = T1; B2 = T3; B3 = T0;
   }

/*************************************************
* Serpent Decryption S-Box 5                     *
*************************************************/
inline void SBoxD5(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   u32bit T0 = B0, T1 = B1, T2 = B2, T3 = B3, T4;
   T4  = T2; T2 &= T3; T2 ^= T1; T1 |= T3; T1 &= T0; T4 ^= T2; T4 ^= T1;
   T1 &= T2; T0 = ~T0; T3 ^= T4; T1 ^= T3; T3 &= T0; T3 ^= T2; T0 ^= T1;
   T2 &= T0; T3 ^= T0; T2 ^= T4; T2 |= T3; T3 ^= T0; T2 ^= T1;
   B0 = T0; B1 = T3; B2 = T2; B3 = T4;
   }

/*************************************************
* Serpent Decryption S-Box 6                     *
*************************************************/
inline void SBoxD6(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   u32bit T0 = B0, T1 = B1, T2 = B2, T3 = B3, T4;
   T1 = ~T1; T4  = T3; T2 ^= T1; T3 |= T0; T3 ^= T2; T2 |= T1; T2 &= T0;
   T4 ^= T3; T2 ^= T4; T4 |= T0; T4 ^= T1; T1 &= T2; T1 ^= T3; T4 ^= T2;
   T3 &= T4; T4 ^= T1; T3 ^= T4; T4 = ~T4; T3 ^= T0;
   B0 = T1; B1 = T4; B2 = T3; B3 = T2;
   }

/*************************************************
* Serpent Decryption S-Box 7                     *
*************************************************/
inline void SBoxD7(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   u32bit T0 = B0, T1 = B1, T2 = B2, T3 = B3, T4;
   T0 ^= T2; T4  = T2; T2 &= T0; T4 ^= T3; T2 = ~T2; T3 ^= T1; T2 ^= T3;
   T4 |= T0; T0 ^= T2; T3 ^= T4; T4 ^= T1; T1 &= T3; T1 ^= T0; T0 ^= T3;
   T0 |= T2; T3 ^= T1; T4 ^= T0;
   B0 = T1; B1 = T2; B2 = T4; B3 = T3;
   }

/*************************************************
* Serpent Decryption S-Box 8                     *
*************************************************/
inline void SBoxD8(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   u32bit T0 = B0, T1 = B1, T2 = B2, T3 = B3, T4;
   T4  = T2; T2 ^= T0; T0 &= T3; T4 |= T3; T2 = ~T2; T3 ^= T1; T1 |= T0;
   T0 ^= T2; T2 &= T4; T3 &= T4; T1 ^= T2; T2 ^= T0; T0 |= T2; T4 ^= T1;
   T0 ^= T3; T3 ^= T4; T4 |= T0; T3 ^= T2; T4 ^= T2;
   B0 = T3; B1 = T0; B2 = T1; B3 = T4;
   }

/*************************************************
* Serpent's Linear Transformation                *
*************************************************/
inline void transform(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   B0  = rotate_left(B0, 13);   B2  = rotate_left(B2, 3);
   B1 ^= B0 ^ B2;               B3 ^= B2 ^ (B0 << 3);
   B1  = rotate_left(B1, 1);    B3  = rotate_left(B3, 7);
   B0 ^= B1 ^ B3;               B2 ^= B3 ^ (B1 << 7);
   B0  = rotate_left(B0, 5);    B2  = rotate_left(B2, 22);
   }

/*************************************************
* Serpent's Inverse Linear Transformation        *
*************************************************/
inline void i_transform(u32bit& B0, u32bit& B1, u32bit& B2, u32bit& B3)
   {
   B2  = rotate_right(B2, 22);  B0  = rotate_right(B0, 5);
   B2 ^= B3 ^ (B1 << 7);        B0 ^= B1 ^ B3;
   B3  = rotate_right(B3, 7);   B1  = rotate_right(B1, 1);
   B3 ^= B2 ^ (B0 << 3);        B1 ^= B0 ^ B2;
   B2  = rotate_right(B2, 3);   B0  = rotate_right(B0, 13);
   }

}

/*************************************************
* XOR a key block with a data block              *
*************************************************/
#define key_xor(round, B0, B1, B2, B3) \
   B0 ^= round_key[4*round  ]; \
   B1 ^= round_key[4*round+1]; \
   B2 ^= round_key[4*round+2]; \
   B3 ^= round_key[4*round+3];

/*************************************************
* Serpent Encryption                             *
*************************************************/
void Serpent::enc(const byte in[], byte out[]) const
   {
   u32bit B0 = make_u32bit(in[ 3], in[ 2], in[ 1], in[ 0]),
          B1 = make_u32bit(in[ 7], in[ 6], in[ 5], in[ 4]),
          B2 = make_u32bit(in[11], in[10], in[ 9], in[ 8]),
          B3 = make_u32bit(in[15], in[14], in[13], in[12]);
   key_xor( 0,B0,B1,B2,B3); SBoxE1(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor( 1,B0,B1,B2,B3); SBoxE2(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor( 2,B0,B1,B2,B3); SBoxE3(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor( 3,B0,B1,B2,B3); SBoxE4(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor( 4,B0,B1,B2,B3); SBoxE5(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor( 5,B0,B1,B2,B3); SBoxE6(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor( 6,B0,B1,B2,B3); SBoxE7(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor( 7,B0,B1,B2,B3); SBoxE8(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor( 8,B0,B1,B2,B3); SBoxE1(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor( 9,B0,B1,B2,B3); SBoxE2(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(10,B0,B1,B2,B3); SBoxE3(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(11,B0,B1,B2,B3); SBoxE4(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(12,B0,B1,B2,B3); SBoxE5(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(13,B0,B1,B2,B3); SBoxE6(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(14,B0,B1,B2,B3); SBoxE7(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(15,B0,B1,B2,B3); SBoxE8(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(16,B0,B1,B2,B3); SBoxE1(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(17,B0,B1,B2,B3); SBoxE2(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(18,B0,B1,B2,B3); SBoxE3(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(19,B0,B1,B2,B3); SBoxE4(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(20,B0,B1,B2,B3); SBoxE5(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(21,B0,B1,B2,B3); SBoxE6(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(22,B0,B1,B2,B3); SBoxE7(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(23,B0,B1,B2,B3); SBoxE8(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(24,B0,B1,B2,B3); SBoxE1(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(25,B0,B1,B2,B3); SBoxE2(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(26,B0,B1,B2,B3); SBoxE3(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(27,B0,B1,B2,B3); SBoxE4(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(28,B0,B1,B2,B3); SBoxE5(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(29,B0,B1,B2,B3); SBoxE6(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(30,B0,B1,B2,B3); SBoxE7(B0,B1,B2,B3); transform(B0,B1,B2,B3);
   key_xor(31,B0,B1,B2,B3); SBoxE8(B0,B1,B2,B3); key_xor(32,B0,B1,B2,B3);
   out[ 0] = get_byte(3, B0); out[ 1] = get_byte(2, B0);
   out[ 2] = get_byte(1, B0); out[ 3] = get_byte(0, B0);
   out[ 4] = get_byte(3, B1); out[ 5] = get_byte(2, B1);
   out[ 6] = get_byte(1, B1); out[ 7] = get_byte(0, B1);
   out[ 8] = get_byte(3, B2); out[ 9] = get_byte(2, B2);
   out[10] = get_byte(1, B2); out[11] = get_byte(0, B2);
   out[12] = get_byte(3, B3); out[13] = get_byte(2, B3);
   out[14] = get_byte(1, B3); out[15] = get_byte(0, B3);
   }

/*************************************************
* Serpent Decryption                             *
*************************************************/
void Serpent::dec(const byte in[], byte out[]) const
   {
   u32bit B0 = make_u32bit(in[ 3], in[ 2], in[ 1], in[ 0]),
          B1 = make_u32bit(in[ 7], in[ 6], in[ 5], in[ 4]),
          B2 = make_u32bit(in[11], in[10], in[ 9], in[ 8]),
          B3 = make_u32bit(in[15], in[14], in[13], in[12]);
   key_xor(32,B0,B1,B2,B3);  SBoxD8(B0,B1,B2,B3); key_xor(31,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD7(B0,B1,B2,B3); key_xor(30,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD6(B0,B1,B2,B3); key_xor(29,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD5(B0,B1,B2,B3); key_xor(28,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD4(B0,B1,B2,B3); key_xor(27,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD3(B0,B1,B2,B3); key_xor(26,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD2(B0,B1,B2,B3); key_xor(25,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD1(B0,B1,B2,B3); key_xor(24,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD8(B0,B1,B2,B3); key_xor(23,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD7(B0,B1,B2,B3); key_xor(22,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD6(B0,B1,B2,B3); key_xor(21,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD5(B0,B1,B2,B3); key_xor(20,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD4(B0,B1,B2,B3); key_xor(19,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD3(B0,B1,B2,B3); key_xor(18,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD2(B0,B1,B2,B3); key_xor(17,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD1(B0,B1,B2,B3); key_xor(16,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD8(B0,B1,B2,B3); key_xor(15,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD7(B0,B1,B2,B3); key_xor(14,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD6(B0,B1,B2,B3); key_xor(13,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD5(B0,B1,B2,B3); key_xor(12,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD4(B0,B1,B2,B3); key_xor(11,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD3(B0,B1,B2,B3); key_xor(10,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD2(B0,B1,B2,B3); key_xor( 9,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD1(B0,B1,B2,B3); key_xor( 8,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD8(B0,B1,B2,B3); key_xor( 7,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD7(B0,B1,B2,B3); key_xor( 6,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD6(B0,B1,B2,B3); key_xor( 5,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD5(B0,B1,B2,B3); key_xor( 4,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD4(B0,B1,B2,B3); key_xor( 3,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD3(B0,B1,B2,B3); key_xor( 2,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD2(B0,B1,B2,B3); key_xor( 1,B0,B1,B2,B3);
   i_transform(B0,B1,B2,B3); SBoxD1(B0,B1,B2,B3); key_xor( 0,B0,B1,B2,B3);
   out[ 0] = get_byte(3, B0); out[ 1] = get_byte(2, B0);
   out[ 2] = get_byte(1, B0); out[ 3] = get_byte(0, B0);
   out[ 4] = get_byte(3, B1); out[ 5] = get_byte(2, B1);
   out[ 6] = get_byte(1, B1); out[ 7] = get_byte(0, B1);
   out[ 8] = get_byte(3, B2); out[ 9] = get_byte(2, B2);
   out[10] = get_byte(1, B2); out[11] = get_byte(0, B2);
   out[12] = get_byte(3, B3); out[13] = get_byte(2, B3);
   out[14] = get_byte(1, B3); out[15] = get_byte(0, B3);
   }

/*************************************************
* Serpent Key Schedule                           *
*************************************************/
void Serpent::key(const byte key[], u32bit length)
   {
   const u32bit PHI = 0x9E3779B9;

   SecureBuffer<u32bit, 140> W;
   for(u32bit j = 0; j != length / 4; ++j)
      W[j] = make_u32bit(key[4*j+3], key[4*j+2], key[4*j+1], key[4*j]);
   W[length / 4] |= u32bit(1) << ((length%4)*8);
   for(u32bit j = 8; j != 140; ++j)
      W[j] = rotate_left(W[j-8] ^ W[j-5] ^ W[j-3] ^ W[j-1] ^ PHI ^ (j-8), 11);
   SBoxE4(W[  8],W[  9],W[ 10],W[ 11]); SBoxE3(W[ 12],W[ 13],W[ 14],W[ 15]);
   SBoxE2(W[ 16],W[ 17],W[ 18],W[ 19]); SBoxE1(W[ 20],W[ 21],W[ 22],W[ 23]);
   SBoxE8(W[ 24],W[ 25],W[ 26],W[ 27]); SBoxE7(W[ 28],W[ 29],W[ 30],W[ 31]);
   SBoxE6(W[ 32],W[ 33],W[ 34],W[ 35]); SBoxE5(W[ 36],W[ 37],W[ 38],W[ 39]);
   SBoxE4(W[ 40],W[ 41],W[ 42],W[ 43]); SBoxE3(W[ 44],W[ 45],W[ 46],W[ 47]);
   SBoxE2(W[ 48],W[ 49],W[ 50],W[ 51]); SBoxE1(W[ 52],W[ 53],W[ 54],W[ 55]);
   SBoxE8(W[ 56],W[ 57],W[ 58],W[ 59]); SBoxE7(W[ 60],W[ 61],W[ 62],W[ 63]);
   SBoxE6(W[ 64],W[ 65],W[ 66],W[ 67]); SBoxE5(W[ 68],W[ 69],W[ 70],W[ 71]);
   SBoxE4(W[ 72],W[ 73],W[ 74],W[ 75]); SBoxE3(W[ 76],W[ 77],W[ 78],W[ 79]);
   SBoxE2(W[ 80],W[ 81],W[ 82],W[ 83]); SBoxE1(W[ 84],W[ 85],W[ 86],W[ 87]);
   SBoxE8(W[ 88],W[ 89],W[ 90],W[ 91]); SBoxE7(W[ 92],W[ 93],W[ 94],W[ 95]);
   SBoxE6(W[ 96],W[ 97],W[ 98],W[ 99]); SBoxE5(W[100],W[101],W[102],W[103]);
   SBoxE4(W[104],W[105],W[106],W[107]); SBoxE3(W[108],W[109],W[110],W[111]);
   SBoxE2(W[112],W[113],W[114],W[115]); SBoxE1(W[116],W[117],W[118],W[119]);
   SBoxE8(W[120],W[121],W[122],W[123]); SBoxE7(W[124],W[125],W[126],W[127]);
   SBoxE6(W[128],W[129],W[130],W[131]); SBoxE5(W[132],W[133],W[134],W[135]);
   SBoxE4(W[136],W[137],W[138],W[139]);
   round_key.copy(W + 8, 132);
   }

}