nextcloud-server/apps/encryption/lib/Command/DisableMasterKey.php

<?php
/**
 * SPDX-FileCopyrightText: 2017 Nextcloud GmbH and Nextcloud contributors
 * SPDX-License-Identifier: AGPL-3.0-or-later
 */
namespace OCA\Encryption\Command;

use OCA\Encryption\Util;
use OCP\IConfig;
use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Helper\QuestionHelper;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\Console\Question\ConfirmationQuestion;

class DisableMasterKey extends Command {

	/** @var Util */
	protected $util;

	/** @var IConfig */
	protected $config;

	/** @var  QuestionHelper */
	protected $questionHelper;

	/**
	 * @param Util $util
	 * @param IConfig $config
	 * @param QuestionHelper $questionHelper
	 */
	public function __construct(Util $util,
		IConfig $config,
		QuestionHelper $questionHelper) {
		$this->util = $util;
		$this->config = $config;
		$this->questionHelper = $questionHelper;
		parent::__construct();
	}

	protected function configure() {
		$this
			->setName('encryption:disable-master-key')
			->setDescription('Disable the master key and use per-user keys instead. Only available for fresh installations with no existing encrypted data! There is no way to enable it again.');
	}

	protected function execute(InputInterface $input, OutputInterface $output): int {
		$isMasterKeyEnabled = $this->util->isMasterKeyEnabled();

		if (!$isMasterKeyEnabled) {
			$output->writeln('Master key already disabled');
		} else {
			$question = new ConfirmationQuestion(
				'Warning: Only perform this operation for a fresh installations with no existing encrypted data! '
				. 'There is no way to enable the master key again. '
				. 'We strongly recommend to keep the master key, it provides significant performance improvements '
				. 'and is easier to handle for both, users and administrators. '
				. 'Do you really want to switch to per-user keys? (y/n) ', false);
			if ($this->questionHelper->ask($input, $output, $question)) {
				$this->config->setAppValue('encryption', 'useMasterKey', '0');
				$output->writeln('Master key successfully disabled.');
			} else {
				$output->writeln('aborted.');
				return 1;
			}
		}
		return 0;
	}
}