server/apps/files_encryption/ajax/userrecovery.php

<?php
/**
 * Copyright (c) 2013, Sam Tuke <samtuke@owncloud.com>
 * This file is licensed under the Affero General Public License version 3 or later.
 * See the COPYING-README file.
 *
 * Script to handle admin settings for encrypted key recovery
 */

use OCA\Encryption;

\OCP\JSON::checkLoggedIn();
\OCP\JSON::checkAppEnabled('files_encryption');
\OCP\JSON::callCheck();

if (
	isset($_POST['userEnableRecovery'])
	&& (0 == $_POST['userEnableRecovery'] || '1' === $_POST['userEnableRecovery'])
) {

	$userId = \OCP\USER::getUser();
	$view = new \OC\Files\View('/');
	$util = new \OCA\Encryption\Util($view, $userId);

	// Save recovery preference to DB
	$return = $util->setRecoveryForUser($_POST['userEnableRecovery']);

	if ($_POST['userEnableRecovery'] === '1') {
		$util->addRecoveryKeys();
	} else {
		$util->removeRecoveryKeys();
	}

} else {

	$return = false;

}

// Return success or failure
($return) ? \OCP\JSON::success() : \OCP\JSON::error();