text: /**
   * \file aes.h
   *
   * \brief AES block cipher
   *
   *  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.
   */
  #ifndef POLARSSL_AES_H
  #define POLARSSL_AES_H
  
  #include <string.h>
  
  #ifdef _MSC_VER
  #include <basetsd.h>
  typedef UINT32 uint32_t;
  #else
  #include <inttypes.h>
  #endif
  
  #define AES_ENCRYPT     1
  #define AES_DECRYPT     0
  
  #define POLARSSL_ERR_AES_INVALID_KEY_LENGTH                -0x0020  /**< Invalid key length. */
  #define POLARSSL_ERR_AES_INVALID_INPUT_LENGTH              -0x0022  /**< Invalid data input length. */
  
  /**
   * \brief          AES context structure
   */
  typedef struct
  {
      int nr;                     /*!<  number of rounds  */
      uint32_t *rk;               /*!<  AES round keys    */
      uint32_t buf[68];           /*!<  unaligned data    */
  }
  aes_context;
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /**
   * \brief          AES key schedule (encryption)
   *
   * \param ctx      AES context to be initialized
   * \param key      encryption key
   * \param keysize  must be 128, 192 or 256
   *
   * \return         0 if successful, or POLARSSL_ERR_AES_INVALID_KEY_LENGTH
   */
  int aes_setkey_enc( aes_context *ctx, const unsigned char *key, unsigned int keysize );
  
  /**
   * \brief          AES key schedule (decryption)
   *
   * \param ctx      AES context to be initialized
   * \param key      decryption key
   * \param keysize  must be 128, 192 or 256
   *
   * \return         0 if successful, or POLARSSL_ERR_AES_INVALID_KEY_LENGTH
   */
  int aes_setkey_dec( aes_context *ctx, const unsigned char *key, unsigned int keysize );
  
  /**
   * \brief          AES-ECB block encryption/decryption
   *
   * \param ctx      AES context
   * \param mode     AES_ENCRYPT or AES_DECRYPT
   * \param input    16-byte input block
   * \param output   16-byte output block
   *
   * \return         0 if successful
   */
  int aes_crypt_ecb( aes_context *ctx,
                      int mode,
                      const unsigned char input[16],
                      unsigned char output[16] );
  
  /**
   * \brief          AES-CBC buffer encryption/decryption
   *                 Length should be a multiple of the block
   *                 size (16 bytes)
   *
   * \param ctx      AES context
   * \param mode     AES_ENCRYPT or AES_DECRYPT
   * \param length   length of the input data
   * \param iv       initialization vector (updated after use)
   * \param input    buffer holding the input data
   * \param output   buffer holding the output data
   *
   * \return         0 if successful, or POLARSSL_ERR_AES_INVALID_INPUT_LENGTH
   */
  int aes_crypt_cbc( aes_context *ctx,
                      int mode,
                      size_t length,
                      unsigned char iv[16],
                      const unsigned char *input,
                      unsigned char *output );
  
  /**
   * \brief          AES-CFB128 buffer encryption/decryption.
   *
   * Note: Due to the nature of CFB you should use the same key schedule for
   * both encryption and decryption. So a context initialized with
   * aes_setkey_enc() for both AES_ENCRYPT and AES_DECRYPT.
   *
   * both 
   * \param ctx      AES context
   * \param mode     AES_ENCRYPT or AES_DECRYPT
   * \param length   length of the input data
   * \param iv_off   offset in IV (updated after use)
   * \param iv       initialization vector (updated after use)
   * \param input    buffer holding the input data
   * \param output   buffer holding the output data
   *
   * \return         0 if successful
   */
  int aes_crypt_cfb128( aes_context *ctx,
                         int mode,
                         size_t length,
                         size_t *iv_off,
                         unsigned char iv[16],
                         const unsigned char *input,
                         unsigned char *output );
  
  /**
   * \brief               AES-CTR buffer encryption/decryption
   *
   * Warning: You have to keep the maximum use of your counter in mind!
   *
   * Note: Due to the nature of CTR you should use the same key schedule for
   * both encryption and decryption. So a context initialized with
   * aes_setkey_enc() for both AES_ENCRYPT and AES_DECRYPT.
   *
   * \param length        The length of the data
   * \param nc_off        The offset in the current stream_block (for resuming
   *                      within current cipher stream). The offset pointer to
   *                      should be 0 at the start of a stream.
   * \param nonce_counter The 128-bit nonce and counter.
   * \param stream_block  The saved stream-block for resuming. Is overwritten
   *                      by the function.
   * \param input         The input data stream
   * \param output        The output data stream
   *
   * \return         0 if successful
   */
  int aes_crypt_ctr( 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 );
  /**
   * \brief          Checkup routine
   *
   * \return         0 if successful, or 1 if the test failed
   */
  int aes_self_test( int verbose );
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* aes.h */
  