DecryptData

NAME
  DecryptData,
  CSSM_DecryptData,
  CSP_DecryptData   - Decrypt buffer data (CDSA)

SYNOPSIS
  # include <cssm.h>

   API:
       CSSM_RETURN CSSMAPI CSSM_DecryptData
       (CSSM_CC_HANDLE CCHandle,
       const CSSM_DATA *CipherBufs,
       uint32 CipherBufCount,
       CSSM_DATA_PTR ClearBufs,
       uint32 ClearBufCount,
       uint32 *bytesDecrypted,
       CSSM_DATA_PTR RemData)
   SPI:
       CSSM_RETURN CSSMCSPI CSP_DecryptData
       (CSSM_CSP_HANDLE CSPHandle,
       CSSM_CC_HANDLE CCHandle,
       const CSSM_CONTEXT *Context,
       const CSSM_DATA *CipherBufs,
       uint32 CipherBufCount,
       CSSM_DATA_PTR ClearBufs,
       uint32 ClearBufCount,
       uint32 *bytesDecrypted,
       CSSM_DATA_PTR RemData,
       CSSM_PRIVILEGE Privilege)

LIBRARY
  Common Security Services Manager library (CDSA$INCSSM300_SHR.EXE)

API PARAMETERS
  CCHandle (input)
          The handle that describes the context of this cryptographic
          operation used to link to the CSP-managed information.

  CipherBufs (input)
          A pointer to a vector of CSSM_DATA structures that contain
          the data to be decrypted.

  CipherBufCount (input)
          The number of CipherBufs.

  ClearBufs (output)
          A pointer to a vector of CSSM_DATA structures that contain
          the decrypted data resulting from the decryption operation.

  ClearBufCount (input)
          The number of ClearBufs.

  bytesDecrypted (output)
          A pointer to uint32 for the size of the decrypted data in
          bytes.

  RemData (output)
          A pointer to the CSSM_DATA structure for the remaining plain
          text if there is not enough buffer space available in the
          output data structures.

SPI PARAMETERS
  CSPHandle (input)
          The handle that describes the add-in cryptographic service
          provider module used to perform calls to CSSM for the
          memory functions managed by CSSM.

  Context (input)
          A pointer to CSSM_CONTEXT structure that describes the
          attributes with this context.

  Privilege (input)
          The export privilege to be applied during the cryptographic
          operation. This parameter is forwarded to the CSP after
          CSSM verifies the caller and service provider privilege set
          includes the specified PRIVILEGE.

DESCRIPTION
  This function decrypts all data contained in the set of input buffers
  using information in the context. The CSSM_QuerySize() (CSSM API), or
  CSP_QuerySize() (CSP SPI), function can be used to estimate the output
  buffer size required. The minimum number of buffers required to contain
  the resulting plain text is produced as output.  If the plain text
  result does not fit within the set of output buffers, the remaining
  plain text is returned in the single output buffer RemData.

  The CSP can require that the cryptographic context include access
  credentials for authentication and authorization checks when using a
  private key or a secret key.

NOTES FOR API
  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,
  pre-allocated 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
  The output is returned to the caller as specified in Buffer Management
  for Cryptographic Services.

RETURN VALUE
  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
  Errors are described in the CDSA technical standard.  See CDSA.

       CSSMERR_CSP_BLOCK_SIZE_MISMATCH
       CSSMERR_CSP_OUTPUT_LENGTH_ERROR

SEE ALSO
  Books

  Intel CDSA Application Developer's Guide (see CDSA)

  Other Help Topics

  Functions for the CSSM API:

      CSSM_QuerySize
      CSSM_EncryptData
      CSSM_DecryptDataInit
      CSSM_DecryptDataUpdate
      CSSM_DecryptDataFinal
      CSSM_DecryptP
      CSSM_DecryptDataInitP

  Functions for the CSP SPI:

      CSP_QuerySize
      CSP_EncryptData
      CSP_DecryptDataInit
      CSP_DecryptDataUpdate
      CSP_DecryptDataFinal