public static function validateResponse( HppResponse $hppResponse, $secret ) {
		self::Initialise();

		if ( ! $hppResponse->isHashValid( $secret ) ) {
			self::$logger->error( "HppResponse contains an invalid security hash." );
			throw new RealexValidationException( "HppResponse contains an invalid security hash", array( "HppResponse contains an invalid security hash" ) );
		}
	}