.. _aesdecryptcbc_cs:



AESDecryptCBC_CS
================


Decrypts plaintext in the CBC ciphertext stealing mode of the AES block
cipher.


Syntax
------


IppStatus ippsAESDecryptCBC_CS1(const Ipp8u\* pSrc, Ipp8u\* pDst, int
len, const IppsAESSpec\* pCtx, const Ipp8u\* pIV);


IppStatus ippsAESDecryptCBC_CS2(const Ipp8u\* pSrc, Ipp8u\* pDst, int
len, const IppsAESSpec\* pCtx, const Ipp8u\* pIV);


IppStatus ippsAESDecryptCBC_CS3(const Ipp8u\* pSrc, Ipp8u\* pDst, int
len, const IppsAESSpec\* pCtx, const Ipp8u\* pIV);


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


``ippcp.h``


Parameters
----------


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

   * - pSrc   
     - Pointer to the input ciphertext data of variable length.
   * - pDst   
     - Pointer to the resulting plaintext data.
   * - len   
     - Length of the input data stream in bytes.
   * - pCtx   
     - Pointer to the IppsAESSpec context.
   * - pIV   
     - Pointer to the initialization vector for the CBC mode operation.




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


These functions decrypt the input data stream according to the three
variants of the Cipher Block Chaining (CBC) mode with Ciphertext
Stealing (CS), as specified in [`NIST SP 800-38A
A. <bibliography.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   
     - For AESDecryptCBC_CS1 and AESDecryptCBC_CS2, indicates an error condition if the input data length is less than the cipher block size.
       For AESDecryptCBC_CS3, indicates an error condition if the input data length is less than or equal to the cipher block size.
   * - ippStsContextMatchErr   
     - Indicates an error condition if the context parameter does not match the operation.