text: /**
   * \file ccm.h
   *
   * \brief Counter with CBC-MAC (CCM) for 128-bit block ciphers
   *
   *  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)
   */
  #ifndef MBEDTLS_CCM_H
  #define MBEDTLS_CCM_H
  
  #include "cipher.h"
  
  #define MBEDTLS_ERR_CCM_BAD_INPUT      -0x000D /**< Bad input parameters to function. */
  #define MBEDTLS_ERR_CCM_AUTH_FAILED    -0x000F /**< Authenticated decryption failed. */
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /**
   * \brief          CCM context structure
   */
  typedef struct {
      mbedtls_cipher_context_t cipher_ctx;    /*!< cipher context used */
  }
  mbedtls_ccm_context;
  
  /**
   * \brief           Initialize CCM context (just makes references valid)
   *                  Makes the context ready for mbedtls_ccm_setkey() or
   *                  mbedtls_ccm_free().
   *
   * \param ctx       CCM context to initialize
   */
  void mbedtls_ccm_init( mbedtls_ccm_context *ctx );
  
  /**
   * \brief           CCM initialization (encryption and decryption)
   *
   * \param ctx       CCM context to be initialized
   * \param cipher    cipher to use (a 128-bit block cipher)
   * \param key       encryption key
   * \param keybits   key size in bits (must be acceptable by the cipher)
   *
   * \return          0 if successful, or a cipher specific error code
   */
  int mbedtls_ccm_setkey( mbedtls_ccm_context *ctx,
                          mbedtls_cipher_id_t cipher,
                          const unsigned char *key,
                          unsigned int keybits );
  
  /**
   * \brief           Free a CCM context and underlying cipher sub-context
   *
   * \param ctx       CCM context to free
   */
  void mbedtls_ccm_free( mbedtls_ccm_context *ctx );
  
  /**
   * \brief           CCM buffer encryption
   *
   * \param ctx       CCM context
   * \param length    length of the input data in bytes
   * \param iv        nonce (initialization vector)
   * \param iv_len    length of IV in bytes
   *                  must be 2, 3, 4, 5, 6, 7 or 8
   * \param add       additional data
   * \param add_len   length of additional data in bytes
   *                  must be less than 2^16 - 2^8
   * \param input     buffer holding the input data
   * \param output    buffer for holding the output data
   *                  must be at least 'length' bytes wide
   * \param tag       buffer for holding the tag
   * \param tag_len   length of the tag to generate in bytes
   *                  must be 4, 6, 8, 10, 14 or 16
   *
   * \note            The tag is written to a separate buffer. To get the tag
   *                  concatenated with the output as in the CCM spec, use
   *                  tag = output + length and make sure the output buffer is
   *                  at least length + tag_len wide.
   *
   * \return          0 if successful
   */
  int mbedtls_ccm_encrypt_and_tag( mbedtls_ccm_context *ctx, size_t length,
                           const unsigned char *iv, size_t iv_len,
                           const unsigned char *add, size_t add_len,
                           const unsigned char *input, unsigned char *output,
                           unsigned char *tag, size_t tag_len );
  
  /**
   * \brief           CCM buffer authenticated decryption
   *
   * \param ctx       CCM context
   * \param length    length of the input data
   * \param iv        initialization vector
   * \param iv_len    length of IV
   * \param add       additional data
   * \param add_len   length of additional data
   * \param input     buffer holding the input data
   * \param output    buffer for holding the output data
   * \param tag       buffer holding the tag
   * \param tag_len   length of the tag
   *
   * \return         0 if successful and authenticated,
   *                 MBEDTLS_ERR_CCM_AUTH_FAILED if tag does not match
   */
  int mbedtls_ccm_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
                        const unsigned char *iv, size_t iv_len,
                        const unsigned char *add, size_t add_len,
                        const unsigned char *input, unsigned char *output,
                        const unsigned char *tag, size_t tag_len );
  
  #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
  /**
   * \brief          Checkup routine
   *
   * \return         0 if successful, or 1 if the test failed
   */
  int mbedtls_ccm_self_test( int verbose );
  #endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* MBEDTLS_CCM_H */
  