.. _mbx_sm4_gcm_update_iv_mb16:

mbx_sm4_gcm_update_iv_mb16
==========================

Processes an initialization vector (IV).

Syntax
------

mbx_status16 mbx_sm4_gcm_update_iv_mb16(const int8u* pa_iv[SM4_LINES], const int iv_len[SM4_LINES], SM4_GCM_CTX_mb16* p_context); 


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

``crypto_mb/sm4_gcm.h``

Parameters
----------

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

   * - pa_iv
     - Array of pointers to the initialization vectors.
   * - iv_len  
     - Array of lengths of the initialization vectors in bytes.
   * - p_context
     - Pointer to the context to keep intermediate results between calls.


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

Processes the initialization vector streams passed by ``pa_iv`` of a variable length passed through the ``iv_len`` array according
to the GCM cipher scheme and updates the context with the processing result.

.. note:: ``mbx_sm4_gcm_update_iv_mb16`` has several call sequence restrictions. See :ref:`sm4_gsm_algorithm_functions` page for details.

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

The ``mbx_sm4_gcm_update_iv_mb16()`` function returns 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.
