RSA Security 5.2.2 manual Final, Data and you know its length, your call is the following

Performing DSA Operations

data and you know its length, your call is the following:

if ((status = B_VerifyUpdate (dsaVerifier, inputData, inputDataLen, (A_SURRENDER_CTX *)NULL_PTR)) != 0)

break;

Step 5: Final

B_VerifyUpdate digested the data. Check the signature with B_VerifyFinal. The Reference Manual Chapter 2 entry on AI_DSAWithSHA1 states:

You must pass a random algorithm in B_SignFinal, but may pass (B_ALGORITHM_OBJ)NULL_PTR for all other randomAlgorithm arguments.

This function does not return immediately, so use a surrender context:

/* generalFlag is for the surrender function. */ generalFlag = 0;

if ((status = B_VerifyFinal (dsaVerifier, signature, signatureLen, (B_ALGORITHM_OBJ)NULL_PTR, &generalSurrenderContext)) != 0)

break;

The return value will be zero if the signature verifies, nonzero if it does not. Of course, a nonzero return value may indicate some other error, so check any error return against the Crypto-C Error Types, Appendix A of the Reference Manual.

Step 6: Destroy

When you are done with all objects, remember to destroy them:

B_DestroyAlgorithmObject (&dsaVerifier);

B_DestroyKeyObject (&dsaPublicKey);

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