code: static void check(PublicKey key, X509CRL crl)
                          throws CertPathValidatorException {
  
          X509CRLImpl x509CRLImpl = null;
          try {
              x509CRLImpl = X509CRLImpl.toImpl(crl);
          } catch (CRLException ce) {
              throw new CertPathValidatorException(ce);
          }
  
          AlgorithmId algorithmId = x509CRLImpl.getSigAlgId();
          check(key, algorithmId);
      }
docs: Check the signature algorithm with the specified public key.
  
  @param key the public key to verify the CRL signature
  @param crl the target CRL