<?php /** * @copyright Copyright (C) 2010-2022, the Friendica project * * @license GNU AGPL version 3 or any later version * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as * published by the Free Software Foundation, either version 3 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see <https://www.gnu.org/licenses/>. * */ namespace Friendica\Util; use Friendica\Core\Logger; use Friendica\Model\APContact; /** * Implements JSON-LD signatures * * Ported from Osada: https://framagit.org/macgirvin/osada */ class LDSignature { public static function isSigned($data) { return !empty($data['signature']); } public static function getSigner($data) { if (!self::isSigned($data)) { return false; } $actor = JsonLD::fetchElement($data, 'actor', 'id'); if (empty($actor) || !is_string($actor)) { return false; } $profile = APContact::getByURL($actor); if (empty($profile['pubkey'])) { return false; } $pubkey = $profile['pubkey']; $ohash = self::hash(self::signableOptions($data['signature'])); $dhash = self::hash(self::signableData($data)); $x = Crypto::rsaVerify($ohash . $dhash, base64_decode($data['signature']['signatureValue']), $pubkey); Logger::notice('LD-verify', ['verified' => (int)$x, 'actor' => $profile['url']]); if (empty($x)) { return false; } else { return $actor; } } public static function sign($data, $owner) { $options = [ 'type' => 'RsaSignature2017', 'nonce' => Strings::getRandomHex(64), 'creator' => $owner['url'] . '#main-key', 'created' => DateTimeFormat::utcNow(DateTimeFormat::ATOM) ]; $ohash = self::hash(self::signableOptions($options)); $dhash = self::hash(self::signableData($data)); $options['signatureValue'] = base64_encode(Crypto::rsaSign($ohash . $dhash, $owner['uprvkey'])); return array_merge($data, ['signature' => $options]); } private static function signableData($data) { unset($data['signature']); return $data; } private static function signableOptions($options) { $newopts = ['@context' => 'https://w3id.org/identity/v1']; unset($options['type']); unset($options['id']); unset($options['signatureValue']); return array_merge($newopts, $options); } private static function hash($obj) { return hash('sha256', JsonLD::normalize($obj)); } }