code: public void verify(PublicKey key)
      throws CRLException, NoSuchAlgorithmException, InvalidKeyException,
             NoSuchProviderException, SignatureException {
          verify(key, "");
      }
docs: Verifies that this CRL was signed using the
  private key that corresponds to the given public key.
  
  @param key the PublicKey used to carry out the verification.
  
  @exception NoSuchAlgorithmException on unsupported signature
  algorithms.
  @exception InvalidKeyException on incorrect key.
  @exception NoSuchProviderException if there's no default provider.
  @exception SignatureException on signature errors.
  @exception CRLException on encoding errors.