/*
 *  FIPS-197 compliant AES implementation
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */
/*
 *  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
 */

#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif

#if defined(MBEDTLS_AES_C)

#include <string.h>

#include "mbedtls/aes.h"
#if defined(MBEDTLS_PADLOCK_C)
#include "mbedtls/padlock.h"
#endif
#if defined(MBEDTLS_AESNI_C)
#include "mbedtls/aesni.h"
#endif

#if !defined(MBEDTLS_AES_ALT)

#include "arc4_alt.h"

/*
 * 32-bit integer manipulation macros (little endian)
 */
#ifndef GET_UINT32_LE
#define GET_UINT32_LE(n,b,i)                            \
{                                                       \
    (n) = ( (uint32_t) (b)[(i)    ]       )             \
        | ( (uint32_t) (b)[(i) + 1] <<  8 )             \
        | ( (uint32_t) (b)[(i) + 2] << 16 )             \
        | ( (uint32_t) (b)[(i) + 3] << 24 );            \
}
#endif

#ifndef PUT_UINT32_LE
#define PUT_UINT32_LE(n,b,i)                                    \
{                                                               \
    (b)[(i)    ] = (unsigned char) ( ( (n)       ) & 0xFF );    \
    (b)[(i) + 1] = (unsigned char) ( ( (n) >>  8 ) & 0xFF );    \
    (b)[(i) + 2] = (unsigned char) ( ( (n) >> 16 ) & 0xFF );    \
    (b)[(i) + 3] = (unsigned char) ( ( (n) >> 24 ) & 0xFF );    \
}
#endif

#if defined(MBEDTLS_PADLOCK_C) &&                      \
    ( defined(MBEDTLS_HAVE_X86) || defined(MBEDTLS_PADLOCK_ALIGN16) )
static int aes_padlock_ace = -1;
#endif

/*
 * Forward S-box & tables
 */
static unsigned char FSb[256];
static uint32_t FT0[256];
static uint32_t FT1[256];
static uint32_t FT2[256];
static uint32_t FT3[256];

/*
 * Reverse S-box & tables
 */
static unsigned char RSb[256];
static uint32_t RT0[256];
static uint32_t RT1[256];
static uint32_t RT2[256];
static uint32_t RT3[256];

/*
 * Round constants
 */
static uint32_t 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] = (uint32_t) 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] = ( (uint32_t) y       ) ^
                 ( (uint32_t) x <<  8 ) ^
                 ( (uint32_t) x << 16 ) ^
                 ( (uint32_t) z << 24 );

        FT1[i] = ROTL8( FT0[i] );
        FT2[i] = ROTL8( FT1[i] );
        FT3[i] = ROTL8( FT2[i] );

        x = RSb[i];

        RT0[i] = ( (uint32_t) MUL( 0x0E, x )       ) ^
                 ( (uint32_t) MUL( 0x09, x ) <<  8 ) ^
                 ( (uint32_t) MUL( 0x0D, x ) << 16 ) ^
                 ( (uint32_t) MUL( 0x0B, x ) << 24 );

        RT1[i] = ROTL8( RT0[i] );
        RT2[i] = ROTL8( RT1[i] );
        RT3[i] = ROTL8( RT2[i] );
    }
}

void mbedtls_aes_init( mbedtls_aes_context *ctx )
{
    memset( ctx, 0, sizeof( mbedtls_aes_context ) );
}

void mbedtls_aes_free( mbedtls_aes_context *ctx )
{
    if( ctx == NULL )
        return;

    mbedtls_zeroize( ctx, sizeof( mbedtls_aes_context ) );
}

/*
 * AES key schedule (encryption)
 */
#if !defined(MBEDTLS_AES_SETKEY_ENC_ALT)
int mbedtls_aes_setkey_enc( mbedtls_aes_context *ctx, const unsigned char *key,
                    unsigned int keybits )
{
    unsigned int i;
    uint32_t *RK;

    if( aes_init_done == 0 )
    {
        aes_gen_tables();
        aes_init_done = 1;

    }

    switch( keybits )
    {
        case 128: ctx->nr = 10; break;
        case 192: ctx->nr = 12; break;
        case 256: ctx->nr = 14; break;
        default : return( MBEDTLS_ERR_AES_INVALID_KEY_LENGTH );
    }

#if defined(MBEDTLS_PADLOCK_C) && defined(MBEDTLS_PADLOCK_ALIGN16)
    if( aes_padlock_ace == -1 )
        aes_padlock_ace = mbedtls_padlock_has_support( MBEDTLS_PADLOCK_ACE );

    if( aes_padlock_ace )
        ctx->rk = RK = MBEDTLS_PADLOCK_ALIGN16( ctx->buf );
    else
#endif
    ctx->rk = RK = ctx->buf;

#if defined(MBEDTLS_AESNI_C) && defined(MBEDTLS_HAVE_X86_64)
    if( mbedtls_aesni_has_support( MBEDTLS_AESNI_AES ) )
        return( mbedtls_aesni_setkey_enc( (unsigned char *) ctx->rk, key, keybits ) );
#endif

    for( i = 0; i < ( keybits >> 5 ); i++ )
    {
        GET_UINT32_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] ^
                ( (uint32_t) FSb[ ( RK[3] >>  8 ) & 0xFF ]       ) ^
                ( (uint32_t) FSb[ ( RK[3] >> 16 ) & 0xFF ] <<  8 ) ^
                ( (uint32_t) FSb[ ( RK[3] >> 24 ) & 0xFF ] << 16 ) ^
                ( (uint32_t) 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] ^
                ( (uint32_t) FSb[ ( RK[5] >>  8 ) & 0xFF ]       ) ^
                ( (uint32_t) FSb[ ( RK[5] >> 16 ) & 0xFF ] <<  8 ) ^
                ( (uint32_t) FSb[ ( RK[5] >> 24 ) & 0xFF ] << 16 ) ^
                ( (uint32_t) 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] ^
                ( (uint32_t) FSb[ ( RK[7] >>  8 ) & 0xFF ]       ) ^
                ( (uint32_t) FSb[ ( RK[7] >> 16 ) & 0xFF ] <<  8 ) ^
                ( (uint32_t) FSb[ ( RK[7] >> 24 ) & 0xFF ] << 16 ) ^
                ( (uint32_t) 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] ^
                ( (uint32_t) FSb[ ( RK[11]       ) & 0xFF ]       ) ^
                ( (uint32_t) FSb[ ( RK[11] >>  8 ) & 0xFF ] <<  8 ) ^
                ( (uint32_t) FSb[ ( RK[11] >> 16 ) & 0xFF ] << 16 ) ^
                ( (uint32_t) 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;
    }

    return( 0 );
}
#endif /* !MBEDTLS_AES_SETKEY_ENC_ALT */

/*
 * AES key schedule (decryption)
 */
#if !defined(MBEDTLS_AES_SETKEY_DEC_ALT)
int mbedtls_aes_setkey_dec( mbedtls_aes_context *ctx, const unsigned char *key,
                    unsigned int keybits )
{
    int i, j, ret;
    mbedtls_aes_context cty;
    uint32_t *RK;
    uint32_t *SK;

    mbedtls_aes_init( &cty );

#if defined(MBEDTLS_PADLOCK_C) && defined(MBEDTLS_PADLOCK_ALIGN16)
    if( aes_padlock_ace == -1 )
        aes_padlock_ace = mbedtls_padlock_has_support( MBEDTLS_PADLOCK_ACE );

    if( aes_padlock_ace )
        ctx->rk = RK = MBEDTLS_PADLOCK_ALIGN16( ctx->buf );
    else
#endif
    ctx->rk = RK = ctx->buf;

    /* Also checks keybits */
    if( ( ret = mbedtls_aes_setkey_enc( &cty, key, keybits ) ) != 0 )
        goto exit;

    ctx->nr = cty.nr;

#if defined(MBEDTLS_AESNI_C) && defined(MBEDTLS_HAVE_X86_64)
    if( mbedtls_aesni_has_support( MBEDTLS_AESNI_AES ) )
    {
        mbedtls_aesni_inverse_key( (unsigned char *) ctx->rk,
                           (const unsigned char *) cty.rk, ctx->nr );
        goto exit;
    }
#endif

    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++;

exit:
    mbedtls_aes_free( &cty );

    return( ret );
}
#endif /* !MBEDTLS_AES_SETKEY_DEC_ALT */

#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
 */
#if !defined(MBEDTLS_AES_ENCRYPT_ALT)
int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
                                  const unsigned char input[16],
                                  unsigned char output[16] )
{
    int i;
    uint32_t *RK, X0, X1, X2, X3, Y0, Y1, Y2, Y3;

    RK = ctx->rk;

    GET_UINT32_LE( X0, input,  0 ); X0 ^= *RK++;
    GET_UINT32_LE( X1, input,  4 ); X1 ^= *RK++;
    GET_UINT32_LE( X2, input,  8 ); X2 ^= *RK++;
    GET_UINT32_LE( X3, input, 12 ); X3 ^= *RK++;

    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++ ^ \
            ( (uint32_t) FSb[ ( Y0       ) & 0xFF ]       ) ^
            ( (uint32_t) FSb[ ( Y1 >>  8 ) & 0xFF ] <<  8 ) ^
            ( (uint32_t) FSb[ ( Y2 >> 16 ) & 0xFF ] << 16 ) ^
            ( (uint32_t) FSb[ ( Y3 >> 24 ) & 0xFF ] << 24 );

    X1 = *RK++ ^ \
            ( (uint32_t) FSb[ ( Y1       ) & 0xFF ]       ) ^
            ( (uint32_t) FSb[ ( Y2 >>  8 ) & 0xFF ] <<  8 ) ^
            ( (uint32_t) FSb[ ( Y3 >> 16 ) & 0xFF ] << 16 ) ^
            ( (uint32_t) FSb[ ( Y0 >> 24 ) & 0xFF ] << 24 );

    X2 = *RK++ ^ \
            ( (uint32_t) FSb[ ( Y2       ) & 0xFF ]       ) ^
            ( (uint32_t) FSb[ ( Y3 >>  8 ) & 0xFF ] <<  8 ) ^
            ( (uint32_t) FSb[ ( Y0 >> 16 ) & 0xFF ] << 16 ) ^
            ( (uint32_t) FSb[ ( Y1 >> 24 ) & 0xFF ] << 24 );

    X3 = *RK++ ^ \
            ( (uint32_t) FSb[ ( Y3       ) & 0xFF ]       ) ^
            ( (uint32_t) FSb[ ( Y0 >>  8 ) & 0xFF ] <<  8 ) ^
            ( (uint32_t) FSb[ ( Y1 >> 16 ) & 0xFF ] << 16 ) ^
            ( (uint32_t) FSb[ ( Y2 >> 24 ) & 0xFF ] << 24 );

    PUT_UINT32_LE( X0, output,  0 );
    PUT_UINT32_LE( X1, output,  4 );
    PUT_UINT32_LE( X2, output,  8 );
    PUT_UINT32_LE( X3, output, 12 );

    return( 0 );
}
#endif /* !MBEDTLS_AES_ENCRYPT_ALT */

/*
 * AES-ECB block decryption
 */
#if !defined(MBEDTLS_AES_DECRYPT_ALT)
int mbedtls_internal_aes_decrypt( mbedtls_aes_context *ctx,
                                  const unsigned char input[16],
                                  unsigned char output[16] )
{
    int i;
    uint32_t *RK, X0, X1, X2, X3, Y0, Y1, Y2, Y3;

    RK = ctx->rk;

    GET_UINT32_LE( X0, input,  0 ); X0 ^= *RK++;
    GET_UINT32_LE( X1, input,  4 ); X1 ^= *RK++;
    GET_UINT32_LE( X2, input,  8 ); X2 ^= *RK++;
    GET_UINT32_LE( X3, input, 12 ); X3 ^= *RK++;

    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++ ^ \
            ( (uint32_t) RSb[ ( Y0       ) & 0xFF ]       ) ^
            ( (uint32_t) RSb[ ( Y3 >>  8 ) & 0xFF ] <<  8 ) ^
            ( (uint32_t) RSb[ ( Y2 >> 16 ) & 0xFF ] << 16 ) ^
            ( (uint32_t) RSb[ ( Y1 >> 24 ) & 0xFF ] << 24 );

    X1 = *RK++ ^ \
            ( (uint32_t) RSb[ ( Y1       ) & 0xFF ]       ) ^
            ( (uint32_t) RSb[ ( Y0 >>  8 ) & 0xFF ] <<  8 ) ^
            ( (uint32_t) RSb[ ( Y3 >> 16 ) & 0xFF ] << 16 ) ^
            ( (uint32_t) RSb[ ( Y2 >> 24 ) & 0xFF ] << 24 );

    X2 = *RK++ ^ \
            ( (uint32_t) RSb[ ( Y2       ) & 0xFF ]       ) ^
            ( (uint32_t) RSb[ ( Y1 >>  8 ) & 0xFF ] <<  8 ) ^
            ( (uint32_t) RSb[ ( Y0 >> 16 ) & 0xFF ] << 16 ) ^
            ( (uint32_t) RSb[ ( Y3 >> 24 ) & 0xFF ] << 24 );

    X3 = *RK++ ^ \
            ( (uint32_t) RSb[ ( Y3       ) & 0xFF ]       ) ^
            ( (uint32_t) RSb[ ( Y2 >>  8 ) & 0xFF ] <<  8 ) ^
            ( (uint32_t) RSb[ ( Y1 >> 16 ) & 0xFF ] << 16 ) ^
            ( (uint32_t) RSb[ ( Y0 >> 24 ) & 0xFF ] << 24 );

    PUT_UINT32_LE( X0, output,  0 );
    PUT_UINT32_LE( X1, output,  4 );
    PUT_UINT32_LE( X2, output,  8 );
    PUT_UINT32_LE( X3, output, 12 );

    return( 0 );
}
#endif /* !MBEDTLS_AES_DECRYPT_ALT */

/*
 * AES-ECB block encryption/decryption
 */
int mbedtls_aes_crypt_ecb( mbedtls_aes_context *ctx,
                    int mode,
                    const unsigned char input[16],
                    unsigned char output[16] )
{
#if defined(MBEDTLS_AESNI_C) && defined(MBEDTLS_HAVE_X86_64)
    if( mbedtls_aesni_has_support( MBEDTLS_AESNI_AES ) )
        return( mbedtls_aesni_crypt_ecb( ctx, mode, input, output ) );
#endif

#if defined(MBEDTLS_PADLOCK_C) && defined(MBEDTLS_HAVE_X86)
    if( aes_padlock_ace )
    {
        if( mbedtls_padlock_xcryptecb( ctx, mode, input, output ) == 0 )
            return( 0 );

        // If padlock data misaligned, we just fall back to
        // unaccelerated mode
        //
    }
#endif

    if( mode == MBEDTLS_AES_ENCRYPT )
        return( mbedtls_internal_aes_encrypt( ctx, input, output ) );
    else
        return( mbedtls_internal_aes_decrypt( ctx, input, output ) );
}

#if defined(MBEDTLS_CIPHER_MODE_CBC)
/*
 * AES-CBC buffer encryption/decryption
 */
int mbedtls_aes_crypt_cbc( mbedtls_aes_context *ctx,
                    int mode,
                    size_t length,
                    unsigned char iv[16],
                    const unsigned char *input,
                    unsigned char *output )
{
    int i;
    unsigned char temp[16];

    if( length % 16 )
        return( MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH );

#if defined(MBEDTLS_PADLOCK_C) && defined(MBEDTLS_HAVE_X86)
    if( aes_padlock_ace )
    {
        if( mbedtls_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 == MBEDTLS_AES_DECRYPT )
    {
        while( length > 0 )
        {
            memcpy( temp, input, 16 );
            mbedtls_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] );

            mbedtls_aes_crypt_ecb( ctx, mode, output, output );
            memcpy( iv, output, 16 );

            input  += 16;
            output += 16;
            length -= 16;
        }
    }

    return( 0 );
}
#endif /* MBEDTLS_CIPHER_MODE_CBC */

#if defined(MBEDTLS_CIPHER_MODE_CFB)
/*
 * AES-CFB128 buffer encryption/decryption
 */
int mbedtls_aes_crypt_cfb128( mbedtls_aes_context *ctx,
                       int mode,
                       size_t length,
                       size_t *iv_off,
                       unsigned char iv[16],
                       const unsigned char *input,
                       unsigned char *output )
{
    int c;
    size_t n = *iv_off;

    if( mode == MBEDTLS_AES_DECRYPT )
    {
        while( length-- )
        {
            if( n == 0 )
                mbedtls_aes_crypt_ecb( ctx, MBEDTLS_AES_ENCRYPT, iv, iv );

            c = *input++;
            *output++ = (unsigned char)( c ^ iv[n] );
            iv[n] = (unsigned char) c;

            n = ( n + 1 ) & 0x0F;
        }
    }
    else
    {
        while( length-- )
        {
            if( n == 0 )
                mbedtls_aes_crypt_ecb( ctx, MBEDTLS_AES_ENCRYPT, iv, iv );

            iv[n] = *output++ = (unsigned char)( iv[n] ^ *input++ );

            n = ( n + 1 ) & 0x0F;
        }
    }

    *iv_off = n;

    return( 0 );
}

/*
 * AES-CFB8 buffer encryption/decryption
 */
int mbedtls_aes_crypt_cfb8( mbedtls_aes_context *ctx,
                       int mode,
                       size_t length,
                       unsigned char iv[16],
                       const unsigned char *input,
                       unsigned char *output )
{
    unsigned char c;
    unsigned char ov[17];

    while( length-- )
    {
        memcpy( ov, iv, 16 );
        mbedtls_aes_crypt_ecb( ctx, MBEDTLS_AES_ENCRYPT, iv, iv );

        if( mode == MBEDTLS_AES_DECRYPT )
            ov[16] = *input;

        c = *output++ = (unsigned char)( iv[0] ^ *input++ );

        if( mode == MBEDTLS_AES_ENCRYPT )
            ov[16] = c;

        memcpy( iv, ov + 1, 16 );
    }

    return( 0 );
}
#endif /*MBEDTLS_CIPHER_MODE_CFB */

#if defined(MBEDTLS_CIPHER_MODE_CTR)
/*
 * AES-CTR buffer encryption/decryption
 */
int mbedtls_aes_crypt_ctr( mbedtls_aes_context *ctx,
                       size_t length,
                       size_t *nc_off,
                       unsigned char nonce_counter[16],
                       unsigned char stream_block[16],
                       const unsigned char *input,
                       unsigned char *output )
{
    int c, i;
    size_t n = *nc_off;

    while( length-- )
    {
        if( n == 0 ) {
            mbedtls_aes_crypt_ecb( ctx, MBEDTLS_AES_ENCRYPT, nonce_counter, stream_block );

            for( i = 16; i > 0; i-- )
                if( ++nonce_counter[i - 1] != 0 )
                    break;
        }
        c = *input++;
        *output++ = (unsigned char)( c ^ stream_block[n] );

        n = ( n + 1 ) & 0x0F;
    }

    *nc_off = n;

    return( 0 );
}
#endif /* MBEDTLS_CIPHER_MODE_CTR */

#endif /* !MBEDTLS_AES_ALT */

#endif /* MBEDTLS_AES_C */