GenerateAlgorithmParams

NAME

CSSM_GenerateAlgorithmParams, CSP_GenerateAlgorithmParams — Generate algorithm parameters (CDSA)

SYNOPSIS

# include <cssm.h>

API:
CSSM_RETURN CSSMAPI CSSM_GenerateAlgorithmParams
(CSSM_CC_HANDLE CCHandle,
uint32 ParamBits,
CSSM_DATA_PTR Param)
SPI:
CSSM_RETURN CSSMCSPI CSP_GenerateAlgorithmParams
(CSSM_CSP_HANDLE CSPHandle,
CSSM_CC_HANDLE CCHandle,
const CSSM_CONTEXT *Context,
uint32 ParamBits,
CSSM_DATA_PTR Param,
uint32 *NumberOfUpdatedAttributes,
CSSM_CONTEXT_ATTRIBUTE_PTR *UpdatedAttributes)

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.
`ParamBits` (`input`)
		Used to generate parameters for the algorithm (for example, Diffie-Hellman).
`Param` (`output`)		Pointer to a CSSM_DATA structure used to provide information to the parameter generation process, or to receive information resulting from the generation process that is not required as a parameter to the algorithm. For instance, phase 2 of the KEA algorithm requires a private random value, rA, and a public version, Ra, to be generated. The private value, rA, is added to the context and the public value, Ra, is returned to the caller. In some cases, when both input and output is required, a data structure is passed to the algorithm. In this situation, `Param->Data` references the structure and `Param->Length` is set to the length of the structure.

SPI PARAMETERS

`CSPHandle` (`input`)
		The handle that describes the add-in Cryptographic Service Provider module used to perform up calls to CSSM for the memory functions managed by CSSM.
`Context` (`input`)		Pointer to CSSM_CONTEXT structure that describes the attributes with this context. Modifying this structure has no effect on the internal structure maintained by the CSSM. It is only a copy of the actual data. Changes to the context attributes must be returned using the `UpdatedAttributes` return parameter.
`NumberOfUpdatedAttributes` (`output`)
		The number of CSSM_CONTEXT_ATTRIBUTE structures contained in the `UpdatedAttributes` array. If this value is zero, `UpdatedAttributes` should be set to NULL.
`UpdatedAttributes` (`output`)
		An array of attributes that will be added to the context should be returned using this parameter. Memory for the attribute structures should be allocated using the CSSM_UPCALLS callbacks provided to the service provider module when `CSSM_SPI_ModuleAttach`() is called.

DESCRIPTION

This function generates algorithm parameters for the specified context. These parameters include Diffie-Hellman key agreement parameters and DSA key generation parameters. In most cases the algorithm parameters will be added directly to the cryptographic context (by returning an array of CSSM_CONTEXT_ATTRIBUTE structures), but an algorithm may return some data to the caller via the Param parameter. The generated parameters are added to the context as an attribute of type CSSM_ATTRIBUTE_ALG_PARAMS. Other attributes returned are added to the context, or replace existing values in the context.

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.

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.

GenerateAlgorithmParams

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