private function check_oauth_signature( $keys, $params ) {

		$http_method = strtoupper( WC()->api->server->method );

		$base_request_uri = rawurlencode( untrailingslashit( get_woocommerce_api_url( '' ) ) . WC()->api->server->path );

		// Get the signature provided by the consumer and remove it from the parameters prior to checking the signature
		$consumer_signature = rawurldecode( str_replace( ' ', '+', $params['oauth_signature'] ) );
		unset( $params['oauth_signature'] );

		// Remove filters and convert them from array to strings to void normalize issues
		if ( isset( $params['filter'] ) ) {
			$filters = $params['filter'];
			unset( $params['filter'] );
			foreach ( $filters as $filter => $filter_value ) {
				$params[ 'filter[' . $filter . ']' ] = $filter_value;
			}
		}

		// Normalize parameter key/values
		$params = $this->normalize_parameters( $params );

		// Sort parameters
		if ( ! uksort( $params, 'strcmp' ) ) {
			throw new Exception( __( 'Invalid signature - failed to sort parameters.', 'woocommerce' ), 401 );
		}

		// Form query string
		$query_params = array();
		foreach ( $params as $param_key => $param_value ) {

			$query_params[] = $param_key . '%3D' . $param_value; // join with equals sign
		}
		$query_string = implode( '%26', $query_params ); // join with ampersand

		$string_to_sign = $http_method . '&' . $base_request_uri . '&' . $query_string;

		if ( 'HMAC-SHA1' !== $params['oauth_signature_method'] && 'HMAC-SHA256' !== $params['oauth_signature_method'] ) {
			throw new Exception( __( 'Invalid signature - signature method is invalid.', 'woocommerce' ), 401 );
		}

		$hash_algorithm = strtolower( str_replace( 'HMAC-', '', $params['oauth_signature_method'] ) );

		$signature = base64_encode( hash_hmac( $hash_algorithm, $string_to_sign, $keys['consumer_secret'], true ) );

		if ( ! hash_equals( $signature, $consumer_signature ) ) {
			throw new Exception( __( 'Invalid signature - provided signature does not match.', 'woocommerce' ), 401 );
		}
	}