NAME    [Toc]    [Back]

       DecryptDataUpdate,   CSSM_DecryptDataUpdate,  CSP_DecryptDataUpdate
 - Continue the staged decryption process (CDSA)

SYNOPSIS    [Toc]    [Back]

       # include <cdsa/cssm.h>

       API:     CSSM_RETURN     CSSMAPI    CSSM_DecryptDataUpdate
       (CSSM_CC_HANDLE  CCHandle,  const  CSSM_DATA  *CipherBufs,
       uint32  CipherBufCount,  CSSM_DATA_PTR  ClearBufs,  uint32
       ClearBufCount, uint32  *bytesDecrypted)  SPI:  CSSM_RETURN
       CSSMCSPI CSP_DecryptDataUpdate (CSSM_CSP_HANDLE CSPHandle,
       CSSM_CC_HANDLE  CCHandle,  const  CSSM_DATA   *CipherBufs,
       uint32  CipherBufCount,  CSSM_DATA_PTR  ClearBufs,  uint32
       ClearBufCount, uint32 *bytesDecrypted)

LIBRARY    [Toc]    [Back]

       Common Security Services Manager library (libcssm.so)

API PARAMETERS    [Toc]    [Back]

       The handle that describes  the  context  of  this  cryptographic
 operation used to link to the CSP-managed information.
  A pointer to a vector of CSSM_DATA structures  that
       contain the data to be operated on.  The number of CipherBufs.
  A pointer to a vector of CSSM_DATA structures  that
       contain  the  decrypted data resulting from the decryption
       operation.  The number of ClearBufs.  A pointer to  uint32
       for the size of the decrypted data in bytes.

SPI PARAMETER    [Toc]    [Back]

       The handle that describes the add-in cryptographic service
       provider module used to perform calls to CSSM for the memory
 functions managed by CSSM.

DESCRIPTION    [Toc]    [Back]

       This function continues the staged decryption process over
       all data in the set of input buffers. There can  be  algorithm-specific
  and  token-specific  rules restricting the
       lengths of data in CSSM_DecryptUpdate() calls, but  multiple
  input  buffers  are  supported. The minimum number of
       buffers required to contain the resulting  plain  text  is
       produced  as  output.  Excess  output  buffer space is not
       remembered across staged  decryption  calls.  Each  staged
       call  begins  filling  one or more new output buffers. The
       CSSM_QuerySize() (CSSM API), or CSP_QuerySize() (CSP SPI),
       function  can  be  used to estimate the output buffer size
       required for each update call.

NOTES FOR API    [Toc]    [Back]

       The output is returned to the caller either by filling the
       caller-specified  buffer  or  by  using  the application's
       declared memory allocation functions  to  allocate  buffer
       space.  To specify a specific, preallocated output buffer,
       the caller must provide an array of one or more  CSSM_DATA
       structures,  each  containing a Length field value greater
       than zero and a non-NULL  data  pointer  field  value.  To
       specify automatic output buffer allocation by the CSP, the
       caller must provide an array  of  one  or  more  CSSM_DATA
       structures,  each containing a Length field value equal to
       zero and a NULL data pointer field value. The  application
       is  always responsible for deallocating the memory when it
       is no longer needed. In-place decryption can  be  done  by
       supplying the same input and output buffers.

NOTES FOR SPI    [Toc]    [Back]

       The  output  is  returned  to  the  caller as specified in
       Buffer Management for Cryptographic Services.

RETURN VALUE    [Toc]    [Back]

       A CSSM_RETURN value indicating  success  or  specifying  a
       particular  error  condition.  The value CSSM_OK indicates
       success. All other values represent an error condition.

ERRORS    [Toc]    [Back]

       Errors are described in the CDSA technical standard.   See
       CDSA_intro(3).

       None specific to this call.

SEE ALSO    [Toc]    [Back]

       Books

       Intel    CDSA    Application    Developer's   Guide   (see
       CDSA_intro(3))

       Reference Pages    [Toc]    [Back]

       Functions for the CSSM API:

       CSSM_QuerySize(3),   CSSM_DecryptData(3),    CSSM_DecryptDataInit(3), CSSM_DecryptDataFinal(3)

       Functions for the CSP SPI:

       CSP_QuerySize(3),     CSP_DecryptData(3),     CSP_DecryptDataInit(3), CSP_DecryptDataFinal(3)



                                             DecryptDataUpdate(3)