.. _mbx_sm4_ccm_encrypt_decrypt_mb16:

mbx_sm4_ccm_encrypt/decrypt_mb16
=================================================

Encrypts plaintext (``ccm_encrypt``) and decrypts ciphertext (``ccm_decrypt``).

Syntax
-------
mbx_status16 mbx_sm4_ccm_encrypt_mb16(int8u* pa_out[SM4_LINES], const int8u* const pa_in[SM4_LINES], const int in_len[SM4_LINES],                           SM4_CCM_CTX_mb16* p_context);

mbx_status16 mbx_sm4_ccm_decrypt_mb16(int8u* pa_out[SM4_LINES], const int8u* const pa_in[SM4_LINES], const int in_len[SM4_LINES],                       SM4_CCM_CTX_mb16* p_context);

Include Files
-------------

``crypto_mb/sm4_ccm.h``

Parameters
----------

.. list-table:: 
   :header-rows: 0

   * - pa_out
     - Array of pointers to the output data streams.
   * - pa_in
     - Array of pointers to the input data streams.
   * - in_len
     - Array of lengths of the input data in bytes.
   * - p_context
     - Pointer to the context to keep intermediate results between calls.



Description
-----------

These functions encrypt/decrypt the input data streams passed by ``pa_in`` of a variable length (up to 2^32 -1 bytes) passed through the ``in_len`` array according to the CCM cipher scheme and store the results into the memory buffers specified in the ``pa_out`` parameter. 
The unctions also update the context with an intermediate hash value.

.. note:: These functions have several call sequence restrictions. See :ref:`sm4_ccm_algorithm_functions` for details.

Return Values
-------------

The ``mbx_sm4_ccm_encrypt_mb16/mbx_sm4_ccm_decrypt_mb16()`` functions return the status that indicates whether the operation is completed successfully or not. 
The status value of 0 indicates that the key schedule is successfully initialized. In case of a non-zero status value, ``MBX_GET_HIGH_PART_STS16()`` and ``MBX_GET_LOW_PART_STS16()``
can help to get the low and high parts of ``mbx_status16``, which can be analyzed separately with the ``MBX_GET_STS()`` call. 
The low part includes the first eight statuses, while the high part includes the remaining eight statuses for each operation.