Initial commit

wp-content/plugins/activitypub/includes/class-signature.php

@@ -0,0 +1,105 @@
+<?php
+namespace Activitypub;
+
+/**
+ * ActivityPub Signature Class
+ *
+ * @author Matthias Pfefferle
+ */
+class Signature {
+
+	/**
+	 * @param int $user_id
+	 *
+	 * @return mixed
+	 */
+	public static function get_public_key( $user_id, $force = false ) {
+		$key = \get_user_meta( $user_id, 'magic_sig_public_key' );
+
+		if ( $key && ! $force ) {
+			return $key[0];
+		}
+
+		self::generate_key_pair( $user_id );
+		$key = \get_user_meta( $user_id, 'magic_sig_public_key' );
+
+		return $key[0];
+	}
+
+	/**
+	 * @param int $user_id
+	 *
+	 * @return mixed
+	 */
+	public static function get_private_key( $user_id, $force = false ) {
+		$key = \get_user_meta( $user_id, 'magic_sig_private_key' );
+
+		if ( $key && ! $force ) {
+			return $key[0];
+		}
+
+		self::generate_key_pair( $user_id );
+		$key = \get_user_meta( $user_id, 'magic_sig_private_key' );
+
+		return $key[0];
+	}
+
+	/**
+	 * Generates the pair keys
+	 *
+	 * @param int $user_id
+	 */
+	public static function generate_key_pair( $user_id ) {
+		$config = array(
+			'digest_alg' => 'sha512',
+			'private_key_bits' => 2048,
+			'private_key_type' => OPENSSL_KEYTYPE_RSA,
+		);
+
+		$key = \openssl_pkey_new( $config );
+		$priv_key = null;
+
+		\openssl_pkey_export( $key, $priv_key );
+
+		// private key
+		\update_user_meta( $user_id, 'magic_sig_private_key', $priv_key );
+
+		$detail = \openssl_pkey_get_details( $key );
+
+		// public key
+		\update_user_meta( $user_id, 'magic_sig_public_key', $detail['key'] );
+	}
+
+	public static function generate_signature( $user_id, $url, $date ) {
+		$key = self::get_private_key( $user_id );
+
+		$url_parts = \wp_parse_url( $url );
+
+		$host = $url_parts['host'];
+		$path = '/';
+
+		// add path
+		if ( ! empty( $url_parts['path'] ) ) {
+			$path = $url_parts['path'];
+		}
+
+		// add query
+		if ( ! empty( $url_parts['query'] ) ) {
+			$path .= '?' . $url_parts['query'];
+		}
+
+		$signed_string = "(request-target): post $path\nhost: $host\ndate: $date";
+
+		$signature = null;
+		\openssl_sign( $signed_string, $signature, $key, OPENSSL_ALGO_SHA256 );
+		$signature = \base64_encode( $signature ); // phpcs:ignore
+
+		$key_id = \get_author_posts_url( $user_id ) . '#main-key';
+
+		return \sprintf( 'keyId="%s",algorithm="rsa-sha256",headers="(request-target) host date",signature="%s"', $key_id, $signature );
+	}
+
+	public static function verify_signature( $headers, $signature ) {
+
+	}
+}