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/**
* AES Source File
* (C) 1999-2007 Jack Lloyd
*/
#include <botan/aes.h>
#include <botan/loadstor.h>
namespace Botan {
/**
* AES Encryption
*/
void AES::enc(const byte in[], byte out[]) const
{
const u32bit* TE0 = TE;
const u32bit* TE1 = TE + 256;
const u32bit* TE2 = TE + 512;
const u32bit* TE3 = TE + 768;
u32bit T0 = load_be<u32bit>(in, 0) ^ EK[0];
u32bit T1 = load_be<u32bit>(in, 1) ^ EK[1];
u32bit T2 = load_be<u32bit>(in, 2) ^ EK[2];
u32bit T3 = load_be<u32bit>(in, 3) ^ EK[3];
u32bit B0, B1, B2, B3;
B0 = TE0[get_byte(0, T0)] ^ TE1[get_byte(1, T1)] ^
TE2[get_byte(2, T2)] ^ TE3[get_byte(3, T3)] ^ EK[4];
B1 = TE0[get_byte(0, T1)] ^ TE1[get_byte(1, T2)] ^
TE2[get_byte(2, T3)] ^ TE3[get_byte(3, T0)] ^ EK[5];
B2 = TE0[get_byte(0, T2)] ^ TE1[get_byte(1, T3)] ^
TE2[get_byte(2, T0)] ^ TE3[get_byte(3, T1)] ^ EK[6];
B3 = TE0[get_byte(0, T3)] ^ TE1[get_byte(1, T0)] ^
TE2[get_byte(2, T1)] ^ TE3[get_byte(3, T2)] ^ EK[7];
for(u32bit j = 2; j != ROUNDS; j += 2)
{
const u32bit K0 = EK[4*j];
const u32bit K1 = EK[4*j+1];
const u32bit K2 = EK[4*j+2];
const u32bit K3 = EK[4*j+3];
T0 = TE0[get_byte(0, B0)] ^ TE1[get_byte(1, B1)] ^
TE2[get_byte(2, B2)] ^ TE3[get_byte(3, B3)] ^ K0;
T1 = TE0[get_byte(0, B1)] ^ TE1[get_byte(1, B2)] ^
TE2[get_byte(2, B3)] ^ TE3[get_byte(3, B0)] ^ K1;
T2 = TE0[get_byte(0, B2)] ^ TE1[get_byte(1, B3)] ^
TE2[get_byte(2, B0)] ^ TE3[get_byte(3, B1)] ^ K2;
T3 = TE0[get_byte(0, B3)] ^ TE1[get_byte(1, B0)] ^
TE2[get_byte(2, B1)] ^ TE3[get_byte(3, B2)] ^ K3;
const u32bit K4 = EK[4*(j+1)+0];
const u32bit K5 = EK[4*(j+1)+1];
const u32bit K6 = EK[4*(j+1)+2];
const u32bit K7 = EK[4*(j+1)+3];
B0 = TE0[get_byte(0, T0)] ^ TE1[get_byte(1, T1)] ^
TE2[get_byte(2, T2)] ^ TE3[get_byte(3, T3)] ^ K4;
B1 = TE0[get_byte(0, T1)] ^ TE1[get_byte(1, T2)] ^
TE2[get_byte(2, T3)] ^ TE3[get_byte(3, T0)] ^ K5;
B2 = TE0[get_byte(0, T2)] ^ TE1[get_byte(1, T3)] ^
TE2[get_byte(2, T0)] ^ TE3[get_byte(3, T1)] ^ K6;
B3 = TE0[get_byte(0, T3)] ^ TE1[get_byte(1, T0)] ^
TE2[get_byte(2, T1)] ^ TE3[get_byte(3, T2)] ^ K7;
}
out[ 0] = SE[get_byte(0, B0)] ^ ME[0];
out[ 1] = SE[get_byte(1, B1)] ^ ME[1];
out[ 2] = SE[get_byte(2, B2)] ^ ME[2];
out[ 3] = SE[get_byte(3, B3)] ^ ME[3];
out[ 4] = SE[get_byte(0, B1)] ^ ME[4];
out[ 5] = SE[get_byte(1, B2)] ^ ME[5];
out[ 6] = SE[get_byte(2, B3)] ^ ME[6];
out[ 7] = SE[get_byte(3, B0)] ^ ME[7];
out[ 8] = SE[get_byte(0, B2)] ^ ME[8];
out[ 9] = SE[get_byte(1, B3)] ^ ME[9];
out[10] = SE[get_byte(2, B0)] ^ ME[10];
out[11] = SE[get_byte(3, B1)] ^ ME[11];
out[12] = SE[get_byte(0, B3)] ^ ME[12];
out[13] = SE[get_byte(1, B0)] ^ ME[13];
out[14] = SE[get_byte(2, B1)] ^ ME[14];
out[15] = SE[get_byte(3, B2)] ^ ME[15];
}
/**
* AES Decryption
*/
void AES::dec(const byte in[], byte out[]) const
{
const u32bit* TD0 = TD;
const u32bit* TD1 = TD + 256;
const u32bit* TD2 = TD + 512;
const u32bit* TD3 = TD + 768;
u32bit B0 = TD0[in[ 0] ^ MD[ 0]] ^ TD1[in[13] ^ MD[13]] ^
TD2[in[10] ^ MD[10]] ^ TD3[in[ 7] ^ MD[ 7]] ^ DK[0];
u32bit B1 = TD0[in[ 4] ^ MD[ 4]] ^ TD1[in[ 1] ^ MD[ 1]] ^
TD2[in[14] ^ MD[14]] ^ TD3[in[11] ^ MD[11]] ^ DK[1];
u32bit B2 = TD0[in[ 8] ^ MD[ 8]] ^ TD1[in[ 5] ^ MD[ 5]] ^
TD2[in[ 2] ^ MD[ 2]] ^ TD3[in[15] ^ MD[15]] ^ DK[2];
u32bit B3 = TD0[in[12] ^ MD[12]] ^ TD1[in[ 9] ^ MD[ 9]] ^
TD2[in[ 6] ^ MD[ 6]] ^ TD3[in[ 3] ^ MD[ 3]] ^ DK[3];
for(u32bit j = 1; j != ROUNDS - 1; j += 2)
{
const u32bit K0 = DK[4*j+0];
const u32bit K1 = DK[4*j+1];
const u32bit K2 = DK[4*j+2];
const u32bit K3 = DK[4*j+3];
const u32bit K4 = DK[4*j+4];
const u32bit K5 = DK[4*j+5];
const u32bit K6 = DK[4*j+6];
const u32bit K7 = DK[4*j+7];
u32bit T0, T1, T2, T3;
T0 = TD0[get_byte(0, B0)] ^ TD1[get_byte(1, B3)] ^
TD2[get_byte(2, B2)] ^ TD3[get_byte(3, B1)] ^ K0;
T1 = TD0[get_byte(0, B1)] ^ TD1[get_byte(1, B0)] ^
TD2[get_byte(2, B3)] ^ TD3[get_byte(3, B2)] ^ K1;
T2 = TD0[get_byte(0, B2)] ^ TD1[get_byte(1, B1)] ^
TD2[get_byte(2, B0)] ^ TD3[get_byte(3, B3)] ^ K2;
T3 = TD0[get_byte(0, B3)] ^ TD1[get_byte(1, B2)] ^
TD2[get_byte(2, B1)] ^ TD3[get_byte(3, B0)] ^ K3;
B0 = TD0[get_byte(0, T0)] ^ TD1[get_byte(1, T3)] ^
TD2[get_byte(2, T2)] ^ TD3[get_byte(3, T1)] ^ K4;
B1 = TD0[get_byte(0, T1)] ^ TD1[get_byte(1, T0)] ^
TD2[get_byte(2, T3)] ^ TD3[get_byte(3, T2)] ^ K5;
B2 = TD0[get_byte(0, T2)] ^ TD1[get_byte(1, T1)] ^
TD2[get_byte(2, T0)] ^ TD3[get_byte(3, T3)] ^ K6;
B3 = TD0[get_byte(0, T3)] ^ TD1[get_byte(1, T2)] ^
TD2[get_byte(2, T1)] ^ TD3[get_byte(3, T0)] ^ K7;
}
out[ 0] = SD[get_byte(0, B0)] ^ MD[16];
out[ 1] = SD[get_byte(1, B3)] ^ MD[17];
out[ 2] = SD[get_byte(2, B2)] ^ MD[18];
out[ 3] = SD[get_byte(3, B1)] ^ MD[19];
out[ 4] = SD[get_byte(0, B1)] ^ MD[20];
out[ 5] = SD[get_byte(1, B0)] ^ MD[21];
out[ 6] = SD[get_byte(2, B3)] ^ MD[22];
out[ 7] = SD[get_byte(3, B2)] ^ MD[23];
out[ 8] = SD[get_byte(0, B2)] ^ MD[24];
out[ 9] = SD[get_byte(1, B1)] ^ MD[25];
out[10] = SD[get_byte(2, B0)] ^ MD[26];
out[11] = SD[get_byte(3, B3)] ^ MD[27];
out[12] = SD[get_byte(0, B3)] ^ MD[28];
out[13] = SD[get_byte(1, B2)] ^ MD[29];
out[14] = SD[get_byte(2, B1)] ^ MD[30];
out[15] = SD[get_byte(3, B0)] ^ MD[31];
}
/**
* AES Key Schedule
*/
void AES::key_schedule(const byte key[], u32bit length)
{
static const u32bit RC[10] = {
0x01000000, 0x02000000, 0x04000000, 0x08000000, 0x10000000, 0x20000000,
0x40000000, 0x80000000, 0x1B000000, 0x36000000 };
ROUNDS = (length / 4) + 6;
SecureBuffer<u32bit, 64> XEK, XDK;
const u32bit X = length / 4;
for(u32bit j = 0; j != X; ++j)
XEK[j] = load_be<u32bit>(key, j);
for(u32bit j = X; j < 4*(ROUNDS+1); j += X)
{
XEK[j] = XEK[j-X] ^ S(rotate_left(XEK[j-1], 8)) ^ RC[(j-X)/X];
for(u32bit k = 1; k != X; ++k)
{
if(X == 8 && k == 4)
XEK[j+k] = XEK[j+k-X] ^ S(XEK[j+k-1]);
else
XEK[j+k] = XEK[j+k-X] ^ XEK[j+k-1];
}
}
for(u32bit j = 0; j != 4*(ROUNDS+1); j += 4)
{
XDK[j ] = XEK[4*ROUNDS-j ];
XDK[j+1] = XEK[4*ROUNDS-j+1];
XDK[j+2] = XEK[4*ROUNDS-j+2];
XDK[j+3] = XEK[4*ROUNDS-j+3];
}
for(u32bit j = 4; j != length + 24; ++j)
XDK[j] = TD[SE[get_byte(0, XDK[j])] + 0] ^
TD[SE[get_byte(1, XDK[j])] + 256] ^
TD[SE[get_byte(2, XDK[j])] + 512] ^
TD[SE[get_byte(3, XDK[j])] + 768];
for(u32bit j = 0; j != 4; ++j)
for(u32bit k = 0; k != 4; ++k)
{
ME[4*j+k ] = get_byte(k, XEK[j+4*ROUNDS]);
MD[4*j+k ] = get_byte(k, XDK[j]);
MD[4*j+k+16] = get_byte(k, XEK[j]);
}
EK.copy(XEK, length + 24);
DK.copy(XDK + 4, length + 20);
}
/**
* AES Byte Substitution
*/
u32bit AES::S(u32bit input)
{
return make_u32bit(SE[get_byte(0, input)], SE[get_byte(1, input)],
SE[get_byte(2, input)], SE[get_byte(3, input)]);
}
/**
* AES Constructor
*/
AES::AES(u32bit key_size) : BlockCipher(16, key_size)
{
if(key_size != 16 && key_size != 24 && key_size != 32)
throw Invalid_Key_Length(name(), key_size);
ROUNDS = (key_size / 4) + 6;
}
/**
* Clear memory of sensitive data
*/
void AES::clear() throw()
{
EK.clear();
DK.clear();
ME.clear();
MD.clear();
}
}
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