76 lines
2.6 KiB
C#
76 lines
2.6 KiB
C#
/*
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Copyright (C) 2011-2015 de4dot@gmail.com
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This file is part of de4dot.
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de4dot is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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de4dot is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with de4dot. If not, see <http://www.gnu.org/licenses/>.
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*/
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using System;
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using System.Text;
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namespace de4dot.code.deobfuscators.SmartAssembly {
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class StringDecrypter {
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int stringOffset;
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byte[] decryptedData;
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StringDecrypterVersion stringDecrypterVersion;
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public bool CanDecrypt {
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get { return decryptedData != null; }
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}
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public StringDecrypterInfo StringDecrypterInfo { get; private set; }
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public StringDecrypter(StringDecrypterInfo stringDecrypterInfo) {
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StringDecrypterInfo = stringDecrypterInfo;
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if (stringDecrypterInfo != null) {
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if (!stringDecrypterInfo.StringsEncrypted) {
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stringOffset = stringDecrypterInfo.StringOffset;
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decryptedData = stringDecrypterInfo.StringsResource.GetResourceData();
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}
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else if (stringDecrypterInfo.CanDecrypt) {
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stringOffset = stringDecrypterInfo.StringOffset;
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decryptedData = stringDecrypterInfo.Decrypt();
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}
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stringDecrypterVersion = StringDecrypterInfo.DecrypterVersion;
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}
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}
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public string Decrypt(int token, int id) {
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if (!CanDecrypt)
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throw new ApplicationException("Can't decrypt strings since decryptedData is null");
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int index = id - (token & 0x00FFFFFF) - stringOffset;
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int len = DeobUtils.ReadVariableLengthInt32(decryptedData, ref index);
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switch (StringDecrypterInfo.DecrypterVersion) {
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case StringDecrypterVersion.V1:
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// Some weird problem with 1.x decrypted strings. They all have a \x01 char at the end.
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var buf = Convert.FromBase64String(Encoding.ASCII.GetString(decryptedData, index, len));
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if (buf.Length % 2 != 0)
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Array.Resize(ref buf, buf.Length - 1);
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return Encoding.Unicode.GetString(buf);
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case StringDecrypterVersion.V2:
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return Encoding.UTF8.GetString(Convert.FromBase64String(Encoding.ASCII.GetString(decryptedData, index, len)));
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default:
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return Encoding.UTF8.GetString(Convert.FromBase64String(Encoding.UTF8.GetString(decryptedData, index, len)));
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}
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}
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}
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}
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