@Override
    public String encode(final Serializable value, final Object[] parameters) {
        return ENCRYPTED_VALUE_PREFIX + super.encode(value, parameters);
    }
Prefix inserted at the beginning of a value to indicate it's encrypted.
support/cas-server-support-oauth-core-api/src/main/java/org/apereo/cas/support/oauth/services/OAuth20RegisteredServiceCipherExecutor.java