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/*
* FIPS-197 compliant AES implementation
*
* Copyright (C) 2011, Con Kolivas <kernel@kolivas.org>
* Copyright (C) 2006-2010, Brainspark B.V.
*
* This file is part of PolarSSL (http://www.polarssl.org)
* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/*
* The AES block cipher was designed by Vincent Rijmen and Joan Daemen.
*
* http://csrc.nist.gov/encryption/aes/rijndael/Rijndael.pdf
* http://csrc.nist.gov/publications/fips/fips197/fips-197.pdf
*/
#include "aes.h"
#include <string.h>
/*
* 32-bit integer manipulation macros (little endian)
*/
#ifndef GET_ULONG_LE
#define GET_ULONG_LE(n,b,i) \
{ \
(n) = ( (unsigned long) (b)[(i) ] ) \
| ( (unsigned long) (b)[(i) + 1] << 8 ) \
| ( (unsigned long) (b)[(i) + 2] << 16 ) \
| ( (unsigned long) (b)[(i) + 3] << 24 ); \
}
#endif
#ifndef PUT_ULONG_LE
#define PUT_ULONG_LE(n,b,i) \
{ \
(b)[(i) ] = (unsigned char) ( (n) ); \
(b)[(i) + 1] = (unsigned char) ( (n) >> 8 ); \
(b)[(i) + 2] = (unsigned char) ( (n) >> 16 ); \
(b)[(i) + 3] = (unsigned char) ( (n) >> 24 ); \
}
#endif
/*
* Forward S-box & tables
*/
static unsigned char FSb[256];
static unsigned long FT0[256];
static unsigned long FT1[256];
static unsigned long FT2[256];
static unsigned long FT3[256];
/*
* Reverse S-box & tables
*/
static unsigned char RSb[256];
static unsigned long RT0[256];
static unsigned long RT1[256];
static unsigned long RT2[256];
static unsigned long RT3[256];
/*
* Round constants
*/
static unsigned long RCON[10];
/*
* Tables generation code
*/
#define ROTL8(x) ( ( x << 8 ) & 0xFFFFFFFF ) | ( x >> 24 )
#define XTIME(x) ( ( x << 1 ) ^ ( ( x & 0x80 ) ? 0x1B : 0x00 ) )
#define MUL(x,y) ( ( x && y ) ? pow[(log[x]+log[y]) % 255] : 0 )
static int aes_init_done = 0;
static void aes_gen_tables( void )
{
int i, x, y, z;
int pow[256];
int log[256];
/*
* compute pow and log tables over GF(2^8)
*/
for( i = 0, x = 1; i < 256; i++ )
{
pow[i] = x;
log[x] = i;
x = ( x ^ XTIME( x ) ) & 0xFF;
}
/*
* calculate the round constants
*/
for( i = 0, x = 1; i < 10; i++ )
{
RCON[i] = (unsigned long) x;
x = XTIME( x ) & 0xFF;
}
/*
* generate the forward and reverse S-boxes
*/
FSb[0x00] = 0x63;
RSb[0x63] = 0x00;
for( i = 1; i < 256; i++ )
{
x = pow[255 - log[i]];
y = x; y = ( (y << 1) | (y >> 7) ) & 0xFF;
x ^= y; y = ( (y << 1) | (y >> 7) ) & 0xFF;
x ^= y; y = ( (y << 1) | (y >> 7) ) & 0xFF;
x ^= y; y = ( (y << 1) | (y >> 7) ) & 0xFF;
x ^= y ^ 0x63;
FSb[i] = (unsigned char) x;
RSb[x] = (unsigned char) i;
}
/*
* generate the forward and reverse tables
*/
for( i = 0; i < 256; i++ )
{
x = FSb[i];
y = XTIME( x ) & 0xFF;
z = ( y ^ x ) & 0xFF;
FT0[i] = ( (unsigned long) y ) ^
( (unsigned long) x << 8 ) ^
( (unsigned long) x << 16 ) ^
( (unsigned long) z << 24 );
FT1[i] = ROTL8( FT0[i] );
FT2[i] = ROTL8( FT1[i] );
FT3[i] = ROTL8( FT2[i] );
x = RSb[i];
RT0[i] = ( (unsigned long) MUL( 0x0E, x ) ) ^
( (unsigned long) MUL( 0x09, x ) << 8 ) ^
( (unsigned long) MUL( 0x0D, x ) << 16 ) ^
( (unsigned long) MUL( 0x0B, x ) << 24 );
RT1[i] = ROTL8( RT0[i] );
RT2[i] = ROTL8( RT1[i] );
RT3[i] = ROTL8( RT2[i] );
}
}
/*
* AES key schedule (encryption)
*/
int aes_setkey_enc( aes_context *ctx, const unsigned char *key, int keysize )
{
int i;
unsigned long *RK;
#if !defined(POLARSSL_AES_ROM_TABLES)
if( aes_init_done == 0 )
{
aes_gen_tables();
aes_init_done = 1;
}
#endif
switch( keysize )
{
case 128: ctx->nr = 10; break;
case 192: ctx->nr = 12; break;
case 256: ctx->nr = 14; break;
default : return( POLARSSL_ERR_AES_INVALID_KEY_LENGTH );
}
#if defined(PADLOCK_ALIGN16)
ctx->rk = RK = PADLOCK_ALIGN16( ctx->buf );
#else
ctx->rk = RK = ctx->buf;
#endif
for( i = 0; i < (keysize >> 5); i++ )
{
GET_ULONG_LE( RK[i], key, i << 2 );
}
switch( ctx->nr )
{
case 10:
for( i = 0; i < 10; i++, RK += 4 )
{
RK[4] = RK[0] ^ RCON[i] ^
( (unsigned long) FSb[ ( RK[3] >> 8 ) & 0xFF ] ) ^
( (unsigned long) FSb[ ( RK[3] >> 16 ) & 0xFF ] << 8 ) ^
( (unsigned long) FSb[ ( RK[3] >> 24 ) & 0xFF ] << 16 ) ^
( (unsigned long) FSb[ ( RK[3] ) & 0xFF ] << 24 );
RK[5] = RK[1] ^ RK[4];
RK[6] = RK[2] ^ RK[5];
RK[7] = RK[3] ^ RK[6];
}
break;
case 12:
for( i = 0; i < 8; i++, RK += 6 )
{
RK[6] = RK[0] ^ RCON[i] ^
( (unsigned long) FSb[ ( RK[5] >> 8 ) & 0xFF ] ) ^
( (unsigned long) FSb[ ( RK[5] >> 16 ) & 0xFF ] << 8 ) ^
( (unsigned long) FSb[ ( RK[5] >> 24 ) & 0xFF ] << 16 ) ^
( (unsigned long) FSb[ ( RK[5] ) & 0xFF ] << 24 );
RK[7] = RK[1] ^ RK[6];
RK[8] = RK[2] ^ RK[7];
RK[9] = RK[3] ^ RK[8];
RK[10] = RK[4] ^ RK[9];
RK[11] = RK[5] ^ RK[10];
}
break;
case 14:
for( i = 0; i < 7; i++, RK += 8 )
{
RK[8] = RK[0] ^ RCON[i] ^
( (unsigned long) FSb[ ( RK[7] >> 8 ) & 0xFF ] ) ^
( (unsigned long) FSb[ ( RK[7] >> 16 ) & 0xFF ] << 8 ) ^
( (unsigned long) FSb[ ( RK[7] >> 24 ) & 0xFF ] << 16 ) ^
( (unsigned long) FSb[ ( RK[7] ) & 0xFF ] << 24 );
RK[9] = RK[1] ^ RK[8];
RK[10] = RK[2] ^ RK[9];
RK[11] = RK[3] ^ RK[10];
RK[12] = RK[4] ^
( (unsigned long) FSb[ ( RK[11] ) & 0xFF ] ) ^
( (unsigned long) FSb[ ( RK[11] >> 8 ) & 0xFF ] << 8 ) ^
( (unsigned long) FSb[ ( RK[11] >> 16 ) & 0xFF ] << 16 ) ^
( (unsigned long) FSb[ ( RK[11] >> 24 ) & 0xFF ] << 24 );
RK[13] = RK[5] ^ RK[12];
RK[14] = RK[6] ^ RK[13];
RK[15] = RK[7] ^ RK[14];
}
break;
default:
break;
}
return( 0 );
}
/*
* AES key schedule (decryption)
*/
int aes_setkey_dec( aes_context *ctx, const unsigned char *key, int keysize )
{
int i, j;
aes_context cty;
unsigned long *RK;
unsigned long *SK;
int ret;
switch( keysize )
{
case 128: ctx->nr = 10; break;
case 192: ctx->nr = 12; break;
case 256: ctx->nr = 14; break;
default : return( POLARSSL_ERR_AES_INVALID_KEY_LENGTH );
}
#if defined(PADLOCK_ALIGN16)
ctx->rk = RK = PADLOCK_ALIGN16( ctx->buf );
#else
ctx->rk = RK = ctx->buf;
#endif
ret = aes_setkey_enc( &cty, key, keysize );
if( ret != 0 )
return( ret );
SK = cty.rk + cty.nr * 4;
*RK++ = *SK++;
*RK++ = *SK++;
*RK++ = *SK++;
*RK++ = *SK++;
for( i = ctx->nr - 1, SK -= 8; i > 0; i--, SK -= 8 )
{
for( j = 0; j < 4; j++, SK++ )
{
*RK++ = RT0[ FSb[ ( *SK ) & 0xFF ] ] ^
RT1[ FSb[ ( *SK >> 8 ) & 0xFF ] ] ^
RT2[ FSb[ ( *SK >> 16 ) & 0xFF ] ] ^
RT3[ FSb[ ( *SK >> 24 ) & 0xFF ] ];
}
}
*RK++ = *SK++;
*RK++ = *SK++;
*RK++ = *SK++;
*RK++ = *SK++;
memset( &cty, 0, sizeof( aes_context ) );
return( 0 );
}
#define AES_FROUND(X0,X1,X2,X3,Y0,Y1,Y2,Y3) \
{ \
X0 = *RK++ ^ FT0[ ( Y0 ) & 0xFF ] ^ \
FT1[ ( Y1 >> 8 ) & 0xFF ] ^ \
FT2[ ( Y2 >> 16 ) & 0xFF ] ^ \
FT3[ ( Y3 >> 24 ) & 0xFF ]; \
\
X1 = *RK++ ^ FT0[ ( Y1 ) & 0xFF ] ^ \
FT1[ ( Y2 >> 8 ) & 0xFF ] ^ \
FT2[ ( Y3 >> 16 ) & 0xFF ] ^ \
FT3[ ( Y0 >> 24 ) & 0xFF ]; \
\
X2 = *RK++ ^ FT0[ ( Y2 ) & 0xFF ] ^ \
FT1[ ( Y3 >> 8 ) & 0xFF ] ^ \
FT2[ ( Y0 >> 16 ) & 0xFF ] ^ \
FT3[ ( Y1 >> 24 ) & 0xFF ]; \
\
X3 = *RK++ ^ FT0[ ( Y3 ) & 0xFF ] ^ \
FT1[ ( Y0 >> 8 ) & 0xFF ] ^ \
FT2[ ( Y1 >> 16 ) & 0xFF ] ^ \
FT3[ ( Y2 >> 24 ) & 0xFF ]; \
}
#define AES_RROUND(X0,X1,X2,X3,Y0,Y1,Y2,Y3) \
{ \
X0 = *RK++ ^ RT0[ ( Y0 ) & 0xFF ] ^ \
RT1[ ( Y3 >> 8 ) & 0xFF ] ^ \
RT2[ ( Y2 >> 16 ) & 0xFF ] ^ \
RT3[ ( Y1 >> 24 ) & 0xFF ]; \
\
X1 = *RK++ ^ RT0[ ( Y1 ) & 0xFF ] ^ \
RT1[ ( Y0 >> 8 ) & 0xFF ] ^ \
RT2[ ( Y3 >> 16 ) & 0xFF ] ^ \
RT3[ ( Y2 >> 24 ) & 0xFF ]; \
\
X2 = *RK++ ^ RT0[ ( Y2 ) & 0xFF ] ^ \
RT1[ ( Y1 >> 8 ) & 0xFF ] ^ \
RT2[ ( Y0 >> 16 ) & 0xFF ] ^ \
RT3[ ( Y3 >> 24 ) & 0xFF ]; \
\
X3 = *RK++ ^ RT0[ ( Y3 ) & 0xFF ] ^ \
RT1[ ( Y2 >> 8 ) & 0xFF ] ^ \
RT2[ ( Y1 >> 16 ) & 0xFF ] ^ \
RT3[ ( Y0 >> 24 ) & 0xFF ]; \
}
/*
* AES-ECB block encryption/decryption
*/
int aes_crypt_ecb( aes_context *ctx,
int mode,
const unsigned char input[16],
unsigned char output[16] )
{
int i;
unsigned long *RK, X0, X1, X2, X3, Y0, Y1, Y2, Y3;
#if defined(POLARSSL_PADLOCK_C) && defined(POLARSSL_HAVE_X86)
if( padlock_supports( PADLOCK_ACE ) )
{
if( padlock_xcryptecb( ctx, mode, input, output ) == 0 )
return( 0 );
// If padlock data misaligned, we just fall back to
// unaccelerated mode
//
}
#endif
RK = ctx->rk;
GET_ULONG_LE( X0, input, 0 ); X0 ^= *RK++;
GET_ULONG_LE( X1, input, 4 ); X1 ^= *RK++;
GET_ULONG_LE( X2, input, 8 ); X2 ^= *RK++;
GET_ULONG_LE( X3, input, 12 ); X3 ^= *RK++;
if( mode == AES_DECRYPT )
{
for( i = (ctx->nr >> 1) - 1; i > 0; i-- )
{
AES_RROUND( Y0, Y1, Y2, Y3, X0, X1, X2, X3 );
AES_RROUND( X0, X1, X2, X3, Y0, Y1, Y2, Y3 );
}
AES_RROUND( Y0, Y1, Y2, Y3, X0, X1, X2, X3 );
X0 = *RK++ ^ \
( (unsigned long) RSb[ ( Y0 ) & 0xFF ] ) ^
( (unsigned long) RSb[ ( Y3 >> 8 ) & 0xFF ] << 8 ) ^
( (unsigned long) RSb[ ( Y2 >> 16 ) & 0xFF ] << 16 ) ^
( (unsigned long) RSb[ ( Y1 >> 24 ) & 0xFF ] << 24 );
X1 = *RK++ ^ \
( (unsigned long) RSb[ ( Y1 ) & 0xFF ] ) ^
( (unsigned long) RSb[ ( Y0 >> 8 ) & 0xFF ] << 8 ) ^
( (unsigned long) RSb[ ( Y3 >> 16 ) & 0xFF ] << 16 ) ^
( (unsigned long) RSb[ ( Y2 >> 24 ) & 0xFF ] << 24 );
X2 = *RK++ ^ \
( (unsigned long) RSb[ ( Y2 ) & 0xFF ] ) ^
( (unsigned long) RSb[ ( Y1 >> 8 ) & 0xFF ] << 8 ) ^
( (unsigned long) RSb[ ( Y0 >> 16 ) & 0xFF ] << 16 ) ^
( (unsigned long) RSb[ ( Y3 >> 24 ) & 0xFF ] << 24 );
X3 = *RK++ ^ \
( (unsigned long) RSb[ ( Y3 ) & 0xFF ] ) ^
( (unsigned long) RSb[ ( Y2 >> 8 ) & 0xFF ] << 8 ) ^
( (unsigned long) RSb[ ( Y1 >> 16 ) & 0xFF ] << 16 ) ^
( (unsigned long) RSb[ ( Y0 >> 24 ) & 0xFF ] << 24 );
}
else /* AES_ENCRYPT */
{
for( i = (ctx->nr >> 1) - 1; i > 0; i-- )
{
AES_FROUND( Y0, Y1, Y2, Y3, X0, X1, X2, X3 );
AES_FROUND( X0, X1, X2, X3, Y0, Y1, Y2, Y3 );
}
AES_FROUND( Y0, Y1, Y2, Y3, X0, X1, X2, X3 );
X0 = *RK++ ^ \
( (unsigned long) FSb[ ( Y0 ) & 0xFF ] ) ^
( (unsigned long) FSb[ ( Y1 >> 8 ) & 0xFF ] << 8 ) ^
( (unsigned long) FSb[ ( Y2 >> 16 ) & 0xFF ] << 16 ) ^
( (unsigned long) FSb[ ( Y3 >> 24 ) & 0xFF ] << 24 );
X1 = *RK++ ^ \
( (unsigned long) FSb[ ( Y1 ) & 0xFF ] ) ^
( (unsigned long) FSb[ ( Y2 >> 8 ) & 0xFF ] << 8 ) ^
( (unsigned long) FSb[ ( Y3 >> 16 ) & 0xFF ] << 16 ) ^
( (unsigned long) FSb[ ( Y0 >> 24 ) & 0xFF ] << 24 );
X2 = *RK++ ^ \
( (unsigned long) FSb[ ( Y2 ) & 0xFF ] ) ^
( (unsigned long) FSb[ ( Y3 >> 8 ) & 0xFF ] << 8 ) ^
( (unsigned long) FSb[ ( Y0 >> 16 ) & 0xFF ] << 16 ) ^
( (unsigned long) FSb[ ( Y1 >> 24 ) & 0xFF ] << 24 );
X3 = *RK++ ^ \
( (unsigned long) FSb[ ( Y3 ) & 0xFF ] ) ^
( (unsigned long) FSb[ ( Y0 >> 8 ) & 0xFF ] << 8 ) ^
( (unsigned long) FSb[ ( Y1 >> 16 ) & 0xFF ] << 16 ) ^
( (unsigned long) FSb[ ( Y2 >> 24 ) & 0xFF ] << 24 );
}
PUT_ULONG_LE( X0, output, 0 );
PUT_ULONG_LE( X1, output, 4 );
PUT_ULONG_LE( X2, output, 8 );
PUT_ULONG_LE( X3, output, 12 );
return( 0 );
}
/*
* AES-CBC buffer encryption/decryption
*/
int aes_crypt_cbc( aes_context *ctx,
int mode,
long long int length,
unsigned char iv[16],
const unsigned char *input,
unsigned char *output )
{
int i;
unsigned char temp[16];
if( length % 16 )
return( POLARSSL_ERR_AES_INVALID_INPUT_LENGTH );
#if defined(POLARSSL_PADLOCK_C) && defined(POLARSSL_HAVE_X86)
if( padlock_supports( PADLOCK_ACE ) )
{
if( padlock_xcryptcbc( ctx, mode, length, iv, input, output ) == 0 )
return( 0 );
// If padlock data misaligned, we just fall back to
// unaccelerated mode
//
}
#endif
if( mode == AES_DECRYPT )
{
while( length > 0 )
{
memcpy( temp, input, 16 );
aes_crypt_ecb( ctx, mode, input, output );
for( i = 0; i < 16; i++ )
output[i] = (unsigned char)( output[i] ^ iv[i] );
memcpy( iv, temp, 16 );
input += 16;
output += 16;
length -= 16;
}
}
else
{
while( length > 0 )
{
for( i = 0; i < 16; i++ )
output[i] = (unsigned char)( input[i] ^ iv[i] );
aes_crypt_ecb( ctx, mode, output, output );
memcpy( iv, output, 16 );
input += 16;
output += 16;
length -= 16;
}
}
return( 0 );
}