NAME
CSSM_DecryptDataUpdate, CSP_DecryptDataUpdate — Continue the staged decryption process (CDSA)
SYNOPSIS
# include <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
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 operated on. |
| 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. |
SPI PARAMETER
| 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. |
DESCRIPTION
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
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
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.
None specific to this call.
SEE ALSO
Books
Intel CDSA Application Developer's Guide
Online Help
Functions for the CSSM API:
CSSM_QuerySize, CSSM_DecryptData, CSSM_DecryptDataInit, CSSM_DecryptDataFinal
Functions for the CSP SPI:
CSP_QuerySize, CSP_DecryptData, CSP_DecryptDataInit, CSP_DecryptDataFinal
