.. _hashgettag:




HashGetTag
==========


Computes the current digest value of the processed part of the message.


Syntax
------


IppStatus ippsHashGetTag(Ipp8u\* pTag, int tagLen, const IppsHashState\*
pCtx);


IppStatus ippsHashGetTag_rmf(Ipp8u\* pTag, int tagLen,
ippsHashState_rmf\* pCtx);


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


``ippcp.h``


Parameters
----------


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

   * -     pTag   
     -  Pointer to the authentication tag.
   * -     tagLen   
     -  The length of the tag (in bytes).
   * -     pCtx   
     -  Pointer to the IppsHashState or IppsHashState_rmf context.




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


The function computes the message digest based on the current context as
specified in [`FIPS PUB
180-2 <bibliography.html>`__],
[`FIPS PUB
180-4 <bibliography.html>`__] and
[`RFC 1321 <bibliography.html>`__].
A call to this function retains the possibility to update the digest.


.. note::


   This function has a *reduced memory footprint* version. To learn
   more, see `Reduced Memory Footprint
   Functions <one-way-hash-primitives.html>`__.


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


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

   * -     ippStsNoErr   
     -  Indicates no error. Any other value indicates an error or warning.
   * -     ippStsNullPtrErr   
     -  Indicates an error condition if any of the specified pointers is NULL.
   * -     ippStsLengthErr   
     -  Indicates an error condition if tagLen < 1 or tagLen exceeds the maximal length of a particular digest.
   * -     ippStsContextMatchErr   
     -  Indicates an error condition if the context parameter does not match the operation.