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/*************************************************
* SEED Source File *
* (C) 1999-2007 The Botan Project *
*************************************************/
#include <botan/seed.h>
#include <botan/bit_ops.h>
namespace Botan {
/*************************************************
* SEED G Function *
*************************************************/
u32bit SEED::G_FUNC::operator()(u32bit X) const
{
return (S0[get_byte(3, X)] ^ S1[get_byte(2, X)] ^
S2[get_byte(1, X)] ^ S3[get_byte(0, X)]);
}
/*************************************************
* SEED Encryption *
*************************************************/
void SEED::enc(const byte in[], byte out[]) const
{
u32bit B0 = make_u32bit(in[ 0], in[ 1], in[ 2], in[ 3]),
B1 = make_u32bit(in[ 4], in[ 5], in[ 6], in[ 7]),
B2 = make_u32bit(in[ 8], in[ 9], in[10], in[11]),
B3 = make_u32bit(in[12], in[13], in[14], in[15]);
G_FUNC G;
for(u32bit j = 0; j != 16; j += 2)
{
u32bit T0, T1;
T0 = B2 ^ K[2*j];
T1 = G(T0 ^ B3 ^ K[2*j+1]);
T0 = G(T1 + T0);
T1 = G(T1 + T0);
B1 ^= T1;
B0 ^= T0 + T1;
T0 = B0 ^ K[2*j+2];
T1 = G(T0 ^ B1 ^ K[2*j+3]);
T0 = G(T1 + T0);
T1 = G(T1 + T0);
B3 ^= T1;
B2 ^= T0 + T1;
}
out[ 0] = get_byte(0, B2); out[ 1] = get_byte(1, B2);
out[ 2] = get_byte(2, B2); out[ 3] = get_byte(3, B2);
out[ 4] = get_byte(0, B3); out[ 5] = get_byte(1, B3);
out[ 6] = get_byte(2, B3); out[ 7] = get_byte(3, B3);
out[ 8] = get_byte(0, B0); out[ 9] = get_byte(1, B0);
out[10] = get_byte(2, B0); out[11] = get_byte(3, B0);
out[12] = get_byte(0, B1); out[13] = get_byte(1, B1);
out[14] = get_byte(2, B1); out[15] = get_byte(3, B1);
}
/*************************************************
* SEED Decryption *
*************************************************/
void SEED::dec(const byte in[], byte out[]) const
{
u32bit B0 = make_u32bit(in[ 0], in[ 1], in[ 2], in[ 3]),
B1 = make_u32bit(in[ 4], in[ 5], in[ 6], in[ 7]),
B2 = make_u32bit(in[ 8], in[ 9], in[10], in[11]),
B3 = make_u32bit(in[12], in[13], in[14], in[15]);
G_FUNC G;
for(u32bit j = 0; j != 16; j += 2)
{
u32bit T0, T1;
T0 = B2 ^ K[30-2*j];
T1 = G(T0 ^ B3 ^ K[31-2*j]);
T0 = G(T1 + T0);
T1 = G(T1 + T0);
B1 ^= T1;
B0 ^= T0 + T1;
T0 = B0 ^ K[28-2*j];
T1 = G(T0 ^ B1 ^ K[29-2*j]);
T0 = G(T1 + T0);
T1 = G(T1 + T0);
B3 ^= T1;
B2 ^= T0 + T1;
}
out[ 0] = get_byte(0, B2); out[ 1] = get_byte(1, B2);
out[ 2] = get_byte(2, B2); out[ 3] = get_byte(3, B2);
out[ 4] = get_byte(0, B3); out[ 5] = get_byte(1, B3);
out[ 6] = get_byte(2, B3); out[ 7] = get_byte(3, B3);
out[ 8] = get_byte(0, B0); out[ 9] = get_byte(1, B0);
out[10] = get_byte(2, B0); out[11] = get_byte(3, B0);
out[12] = get_byte(0, B1); out[13] = get_byte(1, B1);
out[14] = get_byte(2, B1); out[15] = get_byte(3, B1);
}
/*************************************************
* SEED Key Schedule *
*************************************************/
void SEED::key(const byte key[], u32bit)
{
const u32bit RC[16] = {
0x9E3779B9, 0x3C6EF373, 0x78DDE6E6, 0xF1BBCDCC,
0xE3779B99, 0xC6EF3733, 0x8DDE6E67, 0x1BBCDCCF,
0x3779B99E, 0x6EF3733C, 0xDDE6E678, 0xBBCDCCF1,
0x779B99E3, 0xEF3733C6, 0xDE6E678D, 0xBCDCCF1B
};
SecureBuffer<u32bit, 4> WK;
for(u32bit j = 0; j != 4; ++j)
WK[j] = make_u32bit(key[4*j], key[4*j+1], key[4*j+2], key[4*j+3]);
G_FUNC G;
for(u32bit j = 0; j != 16; j += 2)
{
K[2*j ] = G(WK[0] + WK[2] - RC[j]);
K[2*j+1] = G(WK[1] - WK[3] + RC[j]);
byte T = get_byte(3, WK[0]);
WK[0] = (WK[0] >> 8) | (get_byte(3, WK[1]) << 24);
WK[1] = (WK[1] >> 8) | (T << 24);
K[2*j+2] = G(WK[0] + WK[2] - RC[j+1]);
K[2*j+3] = G(WK[1] - WK[3] + RC[j+1]);
T = get_byte(0, WK[3]);
WK[3] = (WK[3] << 8) | get_byte(0, WK[2]);
WK[2] = (WK[2] << 8) | T;
}
}
}
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