SignData

NAME

CSSM_SignData, CSP_SignData — Sign all buffer data (CDSA)

SYNOPSIS

# include <cssm.h>

API:
CSSM_RETURN CSSMAPI CSSM_SignData
(CSSM_CC_HANDLE CCHandle,
const CSSM_DATA *DataBufs,
uint32 DataBufCount,
CSSM_ALGORITHMS DigestAlgorithm,
CSSM_DATA_PTR Signature)
SPI:
CSSM_RETURN CSSMCSPI CSP_SignData
(CSSM_CSP_HANDLE CSPHandle,
CSSM_CC_HANDLE CCHandle,
const CSSM_CONTEXT *Context,
const CSSM_DATA *DataBufs,
uint32 DataBufCount,
CSSM_ALGORITHMS DigestAlgorithm,
CSSM_DATA_PTR Signature)

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.
`DataBufs` (`input`)		A pointer to a vector of CSSM_DATA structures that contain the data to be signed.
`DataBufCount` (`input`)
		The number of DataBufs to be signed.
`DigestAlgorithm` (`input`)
		If signing just a digest, specifies the type of digest. In this case, the context should only specify the encryption algorithm. If not signing just a digest, it must be CSSM_ALGID_NONE. In this case, the context should specify the combination digest/encryption algorithm.
`Signature` (`output`)
		A pointer to the CSSM_DATA structure for the signature.

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.

DESCRIPTION

This function signs all data contained in the set of input buffers using the private key specified in the context. 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.

Signing can include digesting the data and encrypting the digest or signing just the digest (already calculated by the application). If digesting the data and encrypting the digest, then the context should specify the combination digest/encryption algorithm (for example, CSSM_ALGID_MD5WithRSA). In this case, the DigestAlgorithm parameter must be set to CSSM_ALGID_NONE. If signing just the digest, then the context should specify just the encryption algorithm and the DigestAlgorithm parameter should specify the type of digest (for example, CSSM_ALGID_MD5). Also, DataBufCount must be 1.

If the signing algorithm is not reversible or strictly limits the size of the signed data, then the algorithm can specify signing without digesting. In this case, the sign operation is performed on the input data and the size of the input data is restricted by the service provider.

NOTES ON 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.

NOTES ON SPI

The output is returned to the caller as specifed 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.

CSSMERR_CSP_OUTPUT_LENGTH_ERROR
CSSMERR_CSP_INVALID_DIGEST_ALGORITHM

SignData

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