240 lines
6.5 KiB
C#
240 lines
6.5 KiB
C#
/*
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Copyright (C) 2011-2012 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.Collections.Generic;
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using System.Text;
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using dot10.DotNet;
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using de4dot.blocks;
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namespace de4dot.code.deobfuscators.MaxtoCode {
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public class DeobfuscatorInfo : DeobfuscatorInfoBase {
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public const string THE_NAME = "MaxtoCode";
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public const string THE_TYPE = "mc";
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const string DEFAULT_REGEX = @"!^[oO01l]+$&" + DeobfuscatorBase.DEFAULT_VALID_NAME_REGEX;
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IntOption stringCodePage;
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public DeobfuscatorInfo()
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: base(DEFAULT_REGEX) {
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stringCodePage = new IntOption(null, makeArgName("cp"), "String code page", 936);
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}
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public override string Name {
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get { return THE_NAME; }
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}
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public override string Type {
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get { return THE_TYPE; }
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}
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public override IDeobfuscator createDeobfuscator() {
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return new Deobfuscator(new Deobfuscator.Options {
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RenameResourcesInCode = false,
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ValidNameRegex = validNameRegex.get(),
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StringCodePage = stringCodePage.get(),
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});
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}
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protected override IEnumerable<Option> getOptionsInternal() {
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return new List<Option>() {
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stringCodePage,
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};
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}
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}
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class Deobfuscator : DeobfuscatorBase {
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Options options;
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MainType mainType;
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DecrypterInfo decrypterInfo;
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StringDecrypter stringDecrypter;
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internal class Options : OptionsBase {
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public int StringCodePage { get; set; }
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}
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public override string Type {
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get { return DeobfuscatorInfo.THE_TYPE; }
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}
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public override string TypeLong {
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get { return DeobfuscatorInfo.THE_NAME; }
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}
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public override string Name {
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get { return DeobfuscatorInfo.THE_NAME; }
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}
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internal Deobfuscator(Options options)
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: base(options) {
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this.options = options;
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StringFeatures = StringFeatures.AllowStaticDecryption | StringFeatures.AllowDynamicDecryption;
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}
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protected override int detectInternal() {
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int val = 0;
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if (mainType.Detected)
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val = 150;
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return val;
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}
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protected override void scanForObfuscator() {
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mainType = new MainType(module);
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mainType.find();
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}
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public override bool getDecryptedModule(int count, ref byte[] newFileData, ref DumpedMethods dumpedMethods) {
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if (count != 0 || !mainType.Detected)
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return false;
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var fileData = DeobUtils.readModule(module);
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decrypterInfo = new DecrypterInfo(mainType, fileData);
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var methodsDecrypter = new MethodsDecrypter(decrypterInfo);
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if (!methodsDecrypter.decrypt(ref dumpedMethods))
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return false;
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newFileData = fileData;
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return true;
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}
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public override IDeobfuscator moduleReloaded(ModuleDefMD module) {
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var newOne = new Deobfuscator(options);
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newOne.setModule(module);
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newOne.mainType = new MainType(module, mainType);
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newOne.decrypterInfo = decrypterInfo;
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newOne.decrypterInfo.mainType = newOne.mainType;
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return newOne;
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}
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public override void deobfuscateBegin() {
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base.deobfuscateBegin();
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stringDecrypter = new StringDecrypter(decrypterInfo);
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stringDecrypter.find();
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if (stringDecrypter.Detected) {
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stringDecrypter.initialize(getEncoding(options.StringCodePage));
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staticStringInliner.add(stringDecrypter.Method, (method, gim, args) => stringDecrypter.decrypt((uint)args[0]));
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DeobfuscatedFile.stringDecryptersAdded();
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}
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foreach (var method in mainType.InitMethods)
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addCctorInitCallToBeRemoved(method);
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addTypeToBeRemoved(mainType.Type, "Obfuscator type");
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removeDuplicateEmbeddedResources();
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removeInvalidResources();
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}
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static Encoding getEncoding(int cp) {
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try {
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return Encoding.GetEncoding(cp);
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}
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catch {
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Logger.w("Invalid code page {0}!", cp);
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return Encoding.Default;
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}
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}
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class ResourceKey {
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readonly EmbeddedResource resource;
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public ResourceKey(EmbeddedResource resource) {
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this.resource = resource;
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}
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public override int GetHashCode() {
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int hash = 0;
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if (resource.Offset != null)
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hash ^= resource.Offset.GetHashCode();
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hash ^= (int)resource.Data.Position;
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hash ^= (int)resource.Data.Length;
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return hash;
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}
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public override bool Equals(object obj) {
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var other = obj as ResourceKey;
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if (other == null)
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return false;
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return resource.Data.FileOffset == other.resource.Data.FileOffset &&
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resource.Data.Length == other.resource.Data.Length;
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}
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public override string ToString() {
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return resource.Name.String;
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}
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}
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void removeDuplicateEmbeddedResources() {
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var resources = new Dictionary<ResourceKey, List<EmbeddedResource>>();
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foreach (var tmp in module.Resources) {
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var rsrc = tmp as EmbeddedResource;
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if (rsrc == null)
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continue;
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if (rsrc.Offset == null)
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continue;
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List<EmbeddedResource> list;
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var key = new ResourceKey(rsrc);
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if (!resources.TryGetValue(key, out list))
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resources[key] = list = new List<EmbeddedResource>();
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list.Add(rsrc);
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}
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foreach (var list in resources.Values) {
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if (list.Count <= 1)
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continue;
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EmbeddedResource resourceToKeep = null;
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foreach (var rsrc in list) {
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if (UTF8String.IsNullOrEmpty(rsrc.Name))
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continue;
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resourceToKeep = rsrc;
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break;
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}
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if (resourceToKeep == null)
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continue;
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foreach (var rsrc in list) {
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if (rsrc == resourceToKeep)
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continue;
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addResourceToBeRemoved(rsrc, string.Format("Duplicate of resource {0}", Utils.toCsharpString(resourceToKeep.Name)));
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}
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}
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}
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void removeInvalidResources() {
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foreach (var tmp in module.Resources) {
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var resource = tmp as EmbeddedResource;
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if (resource == null)
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continue;
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if (resource.Offset == null || (resource.Data.FileOffset == 0 && resource.Data.Length == 0))
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addResourceToBeRemoved(resource, "Invalid resource");
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}
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}
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public override IEnumerable<int> getStringDecrypterMethods() {
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var list = new List<int>();
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if (stringDecrypter != null && stringDecrypter.Detected)
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list.Add(stringDecrypter.Method.MDToken.ToInt32());
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return list;
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}
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}
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}
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