* @param userName User principal name
     * @param userRealm User realm
     * @return A byte array representing the decrypted data
     * @throws IOException on encoding error
     */
    private byte[] createDecryptedDataBytes(String userName, String userRealm) throws IOException {
        ASN1EncodableVector v = new ASN1EncodableVector();

        // crealm (field 2)