if(CryptVerifySignature(
        hHash, 
        pbSignature, 
        dwSigLen, 
        hPubKey,
        NULL, 
        0)) 

   if(CryptImportKey(
        hProv,
        pbKeyBlob,
        dwBlobLen,
        0,
        0,
        &hPubKey))

 
/**
   * Take a CMS Signed-Data message and a trust anchor and determine if
   * the message is signed with a valid signature from a end entity
   * entity certificate recognized by the trust anchor rootCert.
   */
  public static boolean isValid(
      CMSSignedData signedData, X509Certificate rootCert) throws Exception
  {
      CertStore certsAndCRLs = signedData.getCertificatesAndCRLs(
                                                            "Collection", "BC");
      SignerInformationStore signers = signedData.getSignerInfos();
      Iterator               it = signers.getSigners().iterator();

      if (it.hasNext())
      {
         SignerInformation        signer = (SignerInformation)it.next();
         X509CertSelector         signerConstraints = signer.getSID();

         signerConstraints.setKeyUsage(getKeyUsageForSignature());

         PKIXCertPathBuilderResult result = Utils.buildPath(
                                      rootCert, signer.getSID(), certsAndCRLs);

         return signer.verify(result.getPublicKey(), "BC");
      }
      return false;
    }
}