NAME
   VerifyData,
   CSSM_VerifyData,
   CSP_VerifyData   - Verify input buffer data (CDSA)

 SYNOPSIS
   # include <cssm.h>

    API:
        CSSM_RETURN CSSMAPI CSSM_VerifyData
        (CSSM_CC_HANDLE CCHandle,
        const CSSM_DATA *DataBufs,
        uint32 DataBufCount,
        CSSM_ALGORITHMS DigestAlgorithm,
        const CSSM_DATA *Signature)
    SPI:
        CSSM_RETURN CSSMCSPI CSP_VerifyData
        (CSSM_CSP_HANDLE CSPHandle,
        CSSM_CC_HANDLE CCHandle,
        const CSSM_CONTEXT *Context,
        const CSSM_DATA *DataBufs,
        uint32 DataBufCount,
        CSSM_ALGORITHMS DigestAlgorithm,
        const CSSM_DATA *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 operated on.

   DataBufCount (input)
           The number of DataBufs to be verified.

   DigestAlgorithm (input)
           If verifying just a digest, specifies the type of digest.
           In this case, the context should only specify the encryption
           algorithm. If not verifying just a digest, it must be
           CSSM_ALGID_NONE. In this case, the context should specify
           the combination digest/encryption algorithm.

   Signature (input)
           A pointer to a CSSM_DATA structure which contains the
           signature and the size of 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 verifies all data contained in the set of input
   buffers based on the input signature.

   Verifying can include digesting the data and decrypting the digest
   (from the signature) or verifying just the digest (already calculated
   by the application).  If digesting the data and decrypting the
   digest, then the context should specify both digest and decryption
   algorithms (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 decryption
   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 verification
   without digesting.  In this case, the verify operation is performed
   on the input data and the size of the input data is restricted by the
   service provider.

 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_INPUT_LENGTH_ERROR
        CSSMERR_CSP_VERIFY_FAILED
        CSSMERR_CSP_INVALID_SIGNATURE
        CSSMERR_CSP_INVALID_DIGEST_ALGORITHM

 SEE ALSO
   Books

   Intel CDSA Application Developer's Guide (see CDSA)

   Other Help Topics

   Functions for the CSSM API:

       CSSM_SignData
       CSSM_VerifyDataInit
       CSSM_VerifyDataUpdate
       CSSM_VerifyDataFinal

   Functions for the CSP SPI:

       CSP_SignData
       CSP_VerifyDataInit
       CSP_VerifyDataUpdate
       CSP_VerifyDataFinal