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/*
* Twofish
* (C) 1999-2007,2017 Jack Lloyd
*
* The key schedule implemenation is based on a public domain
* implementation by Matthew Skala
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/twofish.h>
#include <botan/loadstor.h>
#include <botan/rotate.h>
namespace Botan {
namespace {
inline void TF_E(uint32_t A, uint32_t B, uint32_t& C, uint32_t& D,
uint32_t RK1, uint32_t RK2,
const secure_vector<uint32_t>& SB)
{
uint32_t X = SB[ get_byte(3, A)] ^ SB[256+get_byte(2, A)] ^
SB[512+get_byte(1, A)] ^ SB[768+get_byte(0, A)];
uint32_t Y = SB[ get_byte(0, B)] ^ SB[256+get_byte(3, B)] ^
SB[512+get_byte(2, B)] ^ SB[768+get_byte(1, B)];
X += Y;
Y += X;
X += RK1;
Y += RK2;
C = rotr<1>(C ^ X);
D = rotl<1>(D) ^ Y;
}
inline void TF_D(uint32_t A, uint32_t B, uint32_t& C, uint32_t& D,
uint32_t RK1, uint32_t RK2,
const secure_vector<uint32_t>& SB)
{
uint32_t X = SB[ get_byte(3, A)] ^ SB[256+get_byte(2, A)] ^
SB[512+get_byte(1, A)] ^ SB[768+get_byte(0, A)];
uint32_t Y = SB[ get_byte(0, B)] ^ SB[256+get_byte(3, B)] ^
SB[512+get_byte(2, B)] ^ SB[768+get_byte(1, B)];
X += Y;
Y += X;
X += RK1;
Y += RK2;
C = rotl<1>(C) ^ X;
D = rotr<1>(D ^ Y);
}
}
/*
* Twofish Encryption
*/
void Twofish::encrypt_n(const uint8_t in[], uint8_t out[], size_t blocks) const
{
verify_key_set(m_SB.empty() == false);
while(blocks >= 2)
{
uint32_t A0, B0, C0, D0;
uint32_t A1, B1, C1, D1;
load_le(in, A0, B0, C0, D0, A1, B1, C1, D1);
A0 ^= m_RK[0];
A1 ^= m_RK[0];
B0 ^= m_RK[1];
B1 ^= m_RK[1];
C0 ^= m_RK[2];
C1 ^= m_RK[2];
D0 ^= m_RK[3];
D1 ^= m_RK[3];
for(size_t k = 8; k != 40; k += 4)
{
TF_E(A0, B0, C0, D0, m_RK[k+0], m_RK[k+1], m_SB);
TF_E(A1, B1, C1, D1, m_RK[k+0], m_RK[k+1], m_SB);
TF_E(C0, D0, A0, B0, m_RK[k+2], m_RK[k+3], m_SB);
TF_E(C1, D1, A1, B1, m_RK[k+2], m_RK[k+3], m_SB);
}
C0 ^= m_RK[4];
C1 ^= m_RK[4];
D0 ^= m_RK[5];
D1 ^= m_RK[5];
A0 ^= m_RK[6];
A1 ^= m_RK[6];
B0 ^= m_RK[7];
B1 ^= m_RK[7];
store_le(out, C0, D0, A0, B0, C1, D1, A1, B1);
blocks -= 2;
out += 2*BLOCK_SIZE;
in += 2*BLOCK_SIZE;
}
if(blocks)
{
uint32_t A, B, C, D;
load_le(in, A, B, C, D);
A ^= m_RK[0];
B ^= m_RK[1];
C ^= m_RK[2];
D ^= m_RK[3];
for(size_t k = 8; k != 40; k += 4)
{
TF_E(A, B, C, D, m_RK[k ], m_RK[k+1], m_SB);
TF_E(C, D, A, B, m_RK[k+2], m_RK[k+3], m_SB);
}
C ^= m_RK[4];
D ^= m_RK[5];
A ^= m_RK[6];
B ^= m_RK[7];
store_le(out, C, D, A, B);
}
}
/*
* Twofish Decryption
*/
void Twofish::decrypt_n(const uint8_t in[], uint8_t out[], size_t blocks) const
{
verify_key_set(m_SB.empty() == false);
while(blocks >= 2)
{
uint32_t A0, B0, C0, D0;
uint32_t A1, B1, C1, D1;
load_le(in, A0, B0, C0, D0, A1, B1, C1, D1);
A0 ^= m_RK[4];
A1 ^= m_RK[4];
B0 ^= m_RK[5];
B1 ^= m_RK[5];
C0 ^= m_RK[6];
C1 ^= m_RK[6];
D0 ^= m_RK[7];
D1 ^= m_RK[7];
for(size_t k = 40; k != 8; k -= 4)
{
TF_D(A0, B0, C0, D0, m_RK[k-2], m_RK[k-1], m_SB);
TF_D(A1, B1, C1, D1, m_RK[k-2], m_RK[k-1], m_SB);
TF_D(C0, D0, A0, B0, m_RK[k-4], m_RK[k-3], m_SB);
TF_D(C1, D1, A1, B1, m_RK[k-4], m_RK[k-3], m_SB);
}
C0 ^= m_RK[0];
C1 ^= m_RK[0];
D0 ^= m_RK[1];
D1 ^= m_RK[1];
A0 ^= m_RK[2];
A1 ^= m_RK[2];
B0 ^= m_RK[3];
B1 ^= m_RK[3];
store_le(out, C0, D0, A0, B0, C1, D1, A1, B1);
blocks -= 2;
out += 2*BLOCK_SIZE;
in += 2*BLOCK_SIZE;
}
if(blocks)
{
uint32_t A, B, C, D;
load_le(in, A, B, C, D);
A ^= m_RK[4];
B ^= m_RK[5];
C ^= m_RK[6];
D ^= m_RK[7];
for(size_t k = 40; k != 8; k -= 4)
{
TF_D(A, B, C, D, m_RK[k-2], m_RK[k-1], m_SB);
TF_D(C, D, A, B, m_RK[k-4], m_RK[k-3], m_SB);
}
C ^= m_RK[0];
D ^= m_RK[1];
A ^= m_RK[2];
B ^= m_RK[3];
store_le(out, C, D, A, B);
}
}
/*
* Twofish Key Schedule
*/
void Twofish::key_schedule(const uint8_t key[], size_t length)
{
m_SB.resize(1024);
m_RK.resize(40);
secure_vector<uint8_t> S(16);
for(size_t i = 0; i != length; ++i)
{
/*
* Do one column of the RS matrix multiplcation
*/
if(key[i])
{
uint8_t X = POLY_TO_EXP[key[i] - 1];
uint8_t RS1 = RS[(4*i ) % 32];
uint8_t RS2 = RS[(4*i+1) % 32];
uint8_t RS3 = RS[(4*i+2) % 32];
uint8_t RS4 = RS[(4*i+3) % 32];
S[4*(i/8) ] ^= EXP_TO_POLY[(X + POLY_TO_EXP[RS1 - 1]) % 255];
S[4*(i/8)+1] ^= EXP_TO_POLY[(X + POLY_TO_EXP[RS2 - 1]) % 255];
S[4*(i/8)+2] ^= EXP_TO_POLY[(X + POLY_TO_EXP[RS3 - 1]) % 255];
S[4*(i/8)+3] ^= EXP_TO_POLY[(X + POLY_TO_EXP[RS4 - 1]) % 255];
}
}
if(length == 16)
{
for(size_t i = 0; i != 256; ++i)
{
m_SB[ i] = MDS0[Q0[Q0[i]^S[ 0]]^S[ 4]];
m_SB[256+i] = MDS1[Q0[Q1[i]^S[ 1]]^S[ 5]];
m_SB[512+i] = MDS2[Q1[Q0[i]^S[ 2]]^S[ 6]];
m_SB[768+i] = MDS3[Q1[Q1[i]^S[ 3]]^S[ 7]];
}
for(size_t i = 0; i < 40; i += 2)
{
uint32_t X = MDS0[Q0[Q0[i ]^key[ 8]]^key[ 0]] ^
MDS1[Q0[Q1[i ]^key[ 9]]^key[ 1]] ^
MDS2[Q1[Q0[i ]^key[10]]^key[ 2]] ^
MDS3[Q1[Q1[i ]^key[11]]^key[ 3]];
uint32_t Y = MDS0[Q0[Q0[i+1]^key[12]]^key[ 4]] ^
MDS1[Q0[Q1[i+1]^key[13]]^key[ 5]] ^
MDS2[Q1[Q0[i+1]^key[14]]^key[ 6]] ^
MDS3[Q1[Q1[i+1]^key[15]]^key[ 7]];
Y = rotl<8>(Y);
X += Y; Y += X;
m_RK[i] = X;
m_RK[i+1] = rotl<9>(Y);
}
}
else if(length == 24)
{
for(size_t i = 0; i != 256; ++i)
{
m_SB[ i] = MDS0[Q0[Q0[Q1[i]^S[ 0]]^S[ 4]]^S[ 8]];
m_SB[256+i] = MDS1[Q0[Q1[Q1[i]^S[ 1]]^S[ 5]]^S[ 9]];
m_SB[512+i] = MDS2[Q1[Q0[Q0[i]^S[ 2]]^S[ 6]]^S[10]];
m_SB[768+i] = MDS3[Q1[Q1[Q0[i]^S[ 3]]^S[ 7]]^S[11]];
}
for(size_t i = 0; i < 40; i += 2)
{
uint32_t X = MDS0[Q0[Q0[Q1[i ]^key[16]]^key[ 8]]^key[ 0]] ^
MDS1[Q0[Q1[Q1[i ]^key[17]]^key[ 9]]^key[ 1]] ^
MDS2[Q1[Q0[Q0[i ]^key[18]]^key[10]]^key[ 2]] ^
MDS3[Q1[Q1[Q0[i ]^key[19]]^key[11]]^key[ 3]];
uint32_t Y = MDS0[Q0[Q0[Q1[i+1]^key[20]]^key[12]]^key[ 4]] ^
MDS1[Q0[Q1[Q1[i+1]^key[21]]^key[13]]^key[ 5]] ^
MDS2[Q1[Q0[Q0[i+1]^key[22]]^key[14]]^key[ 6]] ^
MDS3[Q1[Q1[Q0[i+1]^key[23]]^key[15]]^key[ 7]];
Y = rotl<8>(Y);
X += Y; Y += X;
m_RK[i] = X;
m_RK[i+1] = rotl<9>(Y);
}
}
else if(length == 32)
{
for(size_t i = 0; i != 256; ++i)
{
m_SB[ i] = MDS0[Q0[Q0[Q1[Q1[i]^S[ 0]]^S[ 4]]^S[ 8]]^S[12]];
m_SB[256+i] = MDS1[Q0[Q1[Q1[Q0[i]^S[ 1]]^S[ 5]]^S[ 9]]^S[13]];
m_SB[512+i] = MDS2[Q1[Q0[Q0[Q0[i]^S[ 2]]^S[ 6]]^S[10]]^S[14]];
m_SB[768+i] = MDS3[Q1[Q1[Q0[Q1[i]^S[ 3]]^S[ 7]]^S[11]]^S[15]];
}
for(size_t i = 0; i < 40; i += 2)
{
uint32_t X = MDS0[Q0[Q0[Q1[Q1[i ]^key[24]]^key[16]]^key[ 8]]^key[ 0]] ^
MDS1[Q0[Q1[Q1[Q0[i ]^key[25]]^key[17]]^key[ 9]]^key[ 1]] ^
MDS2[Q1[Q0[Q0[Q0[i ]^key[26]]^key[18]]^key[10]]^key[ 2]] ^
MDS3[Q1[Q1[Q0[Q1[i ]^key[27]]^key[19]]^key[11]]^key[ 3]];
uint32_t Y = MDS0[Q0[Q0[Q1[Q1[i+1]^key[28]]^key[20]]^key[12]]^key[ 4]] ^
MDS1[Q0[Q1[Q1[Q0[i+1]^key[29]]^key[21]]^key[13]]^key[ 5]] ^
MDS2[Q1[Q0[Q0[Q0[i+1]^key[30]]^key[22]]^key[14]]^key[ 6]] ^
MDS3[Q1[Q1[Q0[Q1[i+1]^key[31]]^key[23]]^key[15]]^key[ 7]];
Y = rotl<8>(Y);
X += Y; Y += X;
m_RK[i] = X;
m_RK[i+1] = rotl<9>(Y);
}
}
}
/*
* Clear memory of sensitive data
*/
void Twofish::clear()
{
zap(m_SB);
zap(m_RK);
}
}