public function receiveData( Net_HTTP_Request_Receiver $request)
	{
		$data	= $request->getRawPostData();
		if( !$data )
			throw new RuntimeException( 'No raw POST data received' );
		$digest	= hash_hmac( "md5", $data, $this->authKey );
		$header	= array_pop( $request->getHeadersByName( $this->headerName ) );
		if( $digest !== $header->getValue() )
			throw new RuntimeException( 'Authentication failed' );
		return $data;
	}