QuerySize

NAME

CSSM_QuerySize, CSP_QuerySize — Get size of the output data (CDSA)

SYNOPSIS

# include <cssm.h>

API:
CSSM_RETURN CSSMAPI CSSM_QuerySize
(CSSM_CC_HANDLE CCHandle,
CSSM_BOOL Encrypt,
uint32 QuerySizeCount,
CSSM_QUERY_SIZE_DATA_PTR DataBlockSizes)
SPI:
CSSM_RETURN CSSMCSPI CSP_QuerySize
(CSSM_CSP_HANDLE CSPHandle,
CSSM_CC_HANDLE CCHandle,
const CSSM_CONTEXT *Context,
CSSM_BOOL Encrypt,
uint32 QuerySizeCount,
CSSM_QUERY_SIZE_DATA_PTR DataBlockSizes)

LIBRARY

Common Security Services Manager library (cdsa$incssm300_shr.exe)

API PARAMETERS

`CCHandle` (`input`)		The handle for an encryption and decryption context.
`Encrypt` (`input`)		A boolean indicating whether encryption is the operation for which the output data size should be calculated. If CSSM_TRUE, the operation is encryption. If CSSM_FALSE the operation is decryption.
`QuerySizeCount` (`input`)
		The number of entries in the array of DataBlockSizes.
`DataBlockSizes` (input/output)
		An array of data block input sizes and corresponding entries for the data block output sizes that are returned by this function.

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`)		Pointer to CSSM_CONTEXT structure that describes the attributes with this context.

DESCRIPTION

This function queries for the size of the output data for a cryptographic operation. If the context is an encryption or decryption context type then the Encrypt parameter will determine which operation is being performed. If Encrypt is set to CSSM_TRUE then it is an encrypt operation, otherwise it is a decrypt operation. For all other context types the Encrypt parameter is ignored. This function can also be used to query the output size requirements for the intermediate steps of a staged cryptographic operation. There may be algorithm-specific and token-specific rules restricting the lengths of data following data update calls.

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.

CSSMERR_CSP_QUERY_SIZE_UNKNOWN

QuerySize

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