/* * * (c) Copyright Ascensio System Limited 2010-2018 * * This program is freeware. You can redistribute it and/or modify it under the terms of the GNU * General Public License (GPL) version 3 as published by the Free Software Foundation (https://www.gnu.org/copyleft/gpl.html). * In accordance with Section 7(a) of the GNU GPL its Section 15 shall be amended to the effect that * Ascensio System SIA expressly excludes the warranty of non-infringement of any third-party rights. * * THIS PROGRAM IS DISTRIBUTED WITHOUT ANY WARRANTY; WITHOUT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY OR * FITNESS FOR A PARTICULAR PURPOSE. For more details, see GNU GPL at https://www.gnu.org/copyleft/gpl.html * * You can contact Ascensio System SIA by email at sales@onlyoffice.com * * The interactive user interfaces in modified source and object code versions of ONLYOFFICE must display * Appropriate Legal Notices, as required under Section 5 of the GNU GPL version 3. * * Pursuant to Section 7 § 3(b) of the GNU GPL you must retain the original ONLYOFFICE logo which contains * relevant author attributions when distributing the software. If the display of the logo in its graphic * form is not reasonably feasible for technical reasons, you must include the words "Powered by ONLYOFFICE" * in every copy of the program you distribute. * Pursuant to Section 7 § 3(e) we decline to grant you any rights under trademark law for use of our trademarks. * */ namespace ASC.Core { public static class Crypto { private static byte[] GetSK1(bool rewrite) { return GetSK(rewrite.GetType().Name.Length); } private static byte[] GetSK2(bool rewrite) { return GetSK(rewrite.GetType().Name.Length * 2); } private static byte[] GetSK(int seed) { var random = new AscRandom(seed); var randomKey = new byte[32]; for (var i = 0; i < randomKey.Length; i++) { randomKey[i] = (byte)random.Next(byte.MaxValue); } return randomKey; } public static string GetV(string data, int keyno, bool reverse) { var hasher = Aes.Create(); hasher.Key = keyno == 1 ? GetSK1(false) : GetSK2(false); hasher.IV = new byte[hasher.BlockSize >> 3]; if (reverse) { using var ms = new MemoryStream(); using var ss = new CryptoStream(ms, hasher.CreateEncryptor(), CryptoStreamMode.Write); using var plainTextStream = new MemoryStream(Convert.FromBase64String(data)); plainTextStream.CopyTo(ss); ss.FlushFinalBlock(); hasher.Clear(); return Convert.ToBase64String(ms.ToArray()); } else { using var ms = new MemoryStream(Convert.FromBase64String(data)); using var ss = new CryptoStream(ms, hasher.CreateDecryptor(), CryptoStreamMode.Read); using var plainTextStream = new MemoryStream(); ss.CopyTo(plainTextStream); hasher.Clear(); return Encoding.Unicode.GetString(plainTextStream.ToArray()); } } internal static byte[] GetV(byte[] data, int keyno, bool reverse) { var hasher = Aes.Create(); hasher.Key = keyno == 1 ? GetSK1(false) : GetSK2(false); hasher.IV = new byte[hasher.BlockSize >> 3]; if (reverse) { using var ms = new MemoryStream(); using var ss = new CryptoStream(ms, hasher.CreateEncryptor(), CryptoStreamMode.Write); using var plainTextStream = new MemoryStream(data); plainTextStream.CopyTo(ss); ss.FlushFinalBlock(); hasher.Clear(); return ms.ToArray(); } else { using var ms = new MemoryStream(data); using var ss = new CryptoStream(ms, hasher.CreateDecryptor(), CryptoStreamMode.Read); using var plainTextStream = new MemoryStream(); ss.CopyTo(plainTextStream); hasher.Clear(); return plainTextStream.ToArray(); } } } }