<?php

declare(strict_types=1);
/**
 * SPDX-FileCopyrightText: 2016-2024 Nextcloud GmbH and Nextcloud contributors
 * SPDX-FileCopyrightText: 2016 ownCloud, Inc.
 * SPDX-License-Identifier: AGPL-3.0-only
 */
namespace OCP\Security;

/**
 * Class Crypto provides a high-level encryption layer using AES-CBC. If no key has been provided
 * it will use the secret defined in config.php as key. Additionally the message will be HMAC'd.
 *
 * Usage:
 * $encryptWithDefaultPassword = \OCP\Server::get(ICrypto::class)->encrypt('EncryptedText');
 * $encryptWithCustomPassword = \OCP\Server::get(ICrypto::class)->encrypt('EncryptedText', 'password');
 *
 * @since 8.0.0
 */
interface ICrypto {
	/**
	 * @param string $message The message to authenticate
	 * @param string $password Password to use (defaults to `secret` in config.php)
	 * @return string Calculated HMAC
	 * @since 8.0.0
	 */
	public function calculateHMAC(string $message, string $password = ''): string;

	/**
	 * Encrypts a value and adds an HMAC (Encrypt-Then-MAC)
	 * @param string $plaintext
	 * @param string $password Password to encrypt, if not specified the secret from config.php will be taken
	 * @return string Authenticated ciphertext
	 * @since 8.0.0
	 */
	public function encrypt(string $plaintext, string $password = ''): string;

	/**
	 * Decrypts a value and verifies the HMAC (Encrypt-Then-Mac)
	 * @param string $authenticatedCiphertext
	 * @param string $password Password to encrypt, if not specified the secret from config.php will be taken
	 * @return string plaintext
	 * @throws \Exception If the HMAC does not match
	 * @throws \Exception If the decryption failed
	 * @since 8.0.0
	 */
	public function decrypt(string $authenticatedCiphertext, string $password = ''): string;
}