515 lines
17 KiB
C#
515 lines
17 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.IO;
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using System.Text;
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using Mono.Cecil;
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using Mono.Cecil.Cil;
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using de4dot.blocks;
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using de4dot.PE;
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namespace de4dot.code.deobfuscators.Confuser {
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abstract class ConstantsDecrypterBase : IVersionProvider {
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protected ModuleDefinition module;
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protected byte[] fileData;
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protected ISimpleDeobfuscator simpleDeobfuscator;
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protected MethodDefinition nativeMethod;
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MethodDefinitionAndDeclaringTypeDict<DecrypterInfo> methodToDecrypterInfo = new MethodDefinitionAndDeclaringTypeDict<DecrypterInfo>();
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FieldDefinitionAndDeclaringTypeDict<bool> fields = new FieldDefinitionAndDeclaringTypeDict<bool>();
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protected EmbeddedResource resource;
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protected BinaryReader reader;
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public class DecrypterInfo {
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public MethodDefinition decryptMethod;
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public uint key0, key1, key2, key3;
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public byte doubleType, singleType, int32Type, int64Type, stringType;
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public void initialize() {
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if (!initializeKeys())
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throw new ApplicationException("Could not find all keys");
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if (!initializeTypeCodes())
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throw new ApplicationException("Could not find all type codes");
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}
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protected virtual bool initializeKeys() {
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if (!findKey0(decryptMethod, out key0))
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return false;
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if (!findKey1(decryptMethod, out key1))
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return false;
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if (!findKey2Key3(decryptMethod, out key2, out key3))
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return false;
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return true;
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}
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protected static bool findKey0(MethodDefinition method, out uint key) {
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count - 5; i++) {
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if (!DotNetUtils.isLdloc(instrs[i]))
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continue;
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if (instrs[i + 1].OpCode.Code != Code.Or)
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continue;
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var ldci4 = instrs[i + 2];
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if (!DotNetUtils.isLdcI4(ldci4))
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continue;
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if (instrs[i + 3].OpCode.Code != Code.Xor)
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continue;
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if (instrs[i + 4].OpCode.Code != Code.Add)
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continue;
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if (!DotNetUtils.isStloc(instrs[i + 5]))
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continue;
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key = (uint)DotNetUtils.getLdcI4Value(ldci4);
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return true;
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}
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key = 0;
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return false;
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}
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static bool findKey1(MethodDefinition method, out uint key) {
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count; i++) {
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int index = ConfuserUtils.findCallMethod(instrs, i, Code.Callvirt, "System.Int32 System.Reflection.MemberInfo::get_MetadataToken()");
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if (index < 0)
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break;
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if (index + 2 > instrs.Count)
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break;
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if (!DotNetUtils.isStloc(instrs[index + 1]))
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continue;
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var ldci4 = instrs[index + 2];
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if (!DotNetUtils.isLdcI4(ldci4))
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continue;
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key = (uint)DotNetUtils.getLdcI4Value(ldci4);
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return true;
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}
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key = 0;
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return false;
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}
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protected static bool findKey2Key3(MethodDefinition method, out uint key2, out uint key3) {
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count - 3; i++) {
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var ldci4_1 = instrs[i];
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if (!DotNetUtils.isLdcI4(ldci4_1))
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continue;
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if (!DotNetUtils.isStloc(instrs[i + 1]))
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continue;
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var ldci4_2 = instrs[i + 2];
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if (!DotNetUtils.isLdcI4(ldci4_2))
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continue;
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if (!DotNetUtils.isStloc(instrs[i + 3]))
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continue;
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key2 = (uint)DotNetUtils.getLdcI4Value(ldci4_1);
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key3 = (uint)DotNetUtils.getLdcI4Value(ldci4_2);
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return true;
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}
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key2 = 0;
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key3 = 0;
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return false;
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}
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bool initializeTypeCodes() {
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var allBlocks = new Blocks(decryptMethod).MethodBlocks.getAllBlocks();
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if (!findTypeCode(allBlocks, out doubleType, Code.Call, "System.Double System.BitConverter::ToDouble(System.Byte[],System.Int32)"))
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return false;
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if (!findTypeCode(allBlocks, out singleType, Code.Call, "System.Single System.BitConverter::ToSingle(System.Byte[],System.Int32)"))
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return false;
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if (!findTypeCode(allBlocks, out int32Type, Code.Call, "System.Int32 System.BitConverter::ToInt32(System.Byte[],System.Int32)"))
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return false;
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if (!findTypeCode(allBlocks, out int64Type, Code.Call, "System.Int64 System.BitConverter::ToInt64(System.Byte[],System.Int32)"))
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return false;
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if (!findTypeCode(allBlocks, out stringType, Code.Callvirt, "System.String System.Text.Encoding::GetString(System.Byte[])") &&
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!findTypeCode(allBlocks, out stringType, Code.Callvirt, "System.String System.Text.Encoding::GetString(System.Byte[],System.Int32,System.Int32)"))
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return false;
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return true;
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}
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static bool findTypeCode(IList<Block> allBlocks, out byte typeCode, Code callCode, string bitConverterMethod) {
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foreach (var block in allBlocks) {
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if (block.Sources.Count != 1)
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continue;
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int index = ConfuserUtils.findCallMethod(block.Instructions, 0, callCode, bitConverterMethod);
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if (index < 0)
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continue;
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if (!findTypeCode(block.Sources[0], out typeCode))
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continue;
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return true;
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}
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typeCode = 0;
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return false;
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}
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static Block fixBlock(Block block) {
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if (block.Sources.Count != 1)
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return block;
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if (block.getOnlyTarget() == null)
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return block;
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if (block.Instructions.Count == 0) {
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}
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else if (block.Instructions.Count == 1 && block.Instructions[0].OpCode.Code == Code.Nop) {
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}
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else
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return block;
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return block.Sources[0];
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}
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static bool findTypeCode(Block block, out byte typeCode) {
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block = fixBlock(block);
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var instrs = block.Instructions;
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int numCeq = 0;
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for (int i = instrs.Count - 1; i >= 0; i--) {
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var instr = instrs[i];
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if (instr.OpCode.Code == Code.Ceq) {
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numCeq++;
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continue;
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}
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if (!DotNetUtils.isLdcI4(instr.Instruction))
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continue;
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if (numCeq != 0 && numCeq != 2)
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continue;
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typeCode = (byte)DotNetUtils.getLdcI4Value(instr.Instruction);
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return true;
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}
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typeCode = 0;
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return false;
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}
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public uint calcHash(uint x) {
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uint h0 = key1 ^ x;
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uint h1 = key2;
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uint h2 = key3;
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for (uint i = 1; i <= 64; i++) {
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h0 = (h0 << 8) | (h0 >> 24);
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uint n = h0 & 0x3F;
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if (n >= 0 && n < 16) {
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h1 |= ((byte)(h0 >> 8) & (h0 >> 16)) ^ (byte)~h0;
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h2 ^= (h0 * i + 1) & 0xF;
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h0 += (h1 | h2) ^ key0;
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}
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else if (n >= 16 && n < 32) {
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h1 ^= ((h0 & 0x00FF00FF) << 8) ^ (ushort)((h0 >> 8) | ~h0);
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h2 += (h0 * i) & 0x1F;
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h0 |= (h1 + ~h2) & key0;
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}
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else if (n >= 32 && n < 48) {
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h1 += (byte)(h0 | (h0 >> 16)) + (~h0 & 0xFF);
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h2 -= ~(h0 + n) % 48;
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h0 ^= (h1 % h2) | key0;
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}
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else if (n >= 48 && n < 64) {
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h1 ^= ((byte)(h0 >> 16) | ~(h0 & 0xFF)) * (~h0 & 0x00FF0000);
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h2 += (h0 ^ (i - 1)) % n;
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h0 -= ~(h1 ^ h2) + key0;
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}
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}
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return h0;
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}
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}
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public abstract bool Detected { get; }
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public MethodDefinition NativeMethod {
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get { return nativeMethod; }
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}
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public EmbeddedResource Resource {
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get { return resource; }
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}
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public IEnumerable<FieldDefinition> Fields {
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get { return fields.getKeys(); }
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}
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protected bool HasDecrypterInfos {
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get { return methodToDecrypterInfo.Count > 0; }
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}
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public IEnumerable<DecrypterInfo> DecrypterInfos {
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get { return methodToDecrypterInfo.getValues(); }
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}
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public ConstantsDecrypterBase(ModuleDefinition module, byte[] fileData, ISimpleDeobfuscator simpleDeobfuscator) {
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this.module = module;
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this.fileData = fileData;
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this.simpleDeobfuscator = simpleDeobfuscator;
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}
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public abstract bool getRevisionRange(out int minRev, out int maxRev);
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public abstract void initialize();
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protected void add(DecrypterInfo info) {
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methodToDecrypterInfo.add(info.decryptMethod, info);
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}
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protected bool add(FieldDefinition field) {
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if (field == null)
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return false;
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fields.add(field, true);
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return true;
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}
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protected void initializeDecrypterInfos() {
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foreach (var info in methodToDecrypterInfo.getValues()) {
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simpleDeobfuscator.deobfuscate(info.decryptMethod);
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info.initialize();
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}
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}
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protected void setConstantsData(byte[] constants) {
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reader = new BinaryReader(new MemoryStream(constants));
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}
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protected EmbeddedResource findResource(MethodDefinition method) {
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return DotNetUtils.getResource(module, DotNetUtils.getCodeStrings(method)) as EmbeddedResource;
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}
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protected static MethodDefinition findNativeMethod(MethodDefinition method) {
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count; i++) {
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var call = instrs[i];
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if (call.OpCode.Code != Code.Call)
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continue;
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var calledMethod = call.Operand as MethodDefinition;
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if (calledMethod == null || !calledMethod.IsStatic || !calledMethod.IsNative)
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continue;
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if (!DotNetUtils.isMethod(calledMethod, "System.Int32", "(System.Int32)"))
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continue;
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return calledMethod;
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}
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return null;
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}
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static VariableDefinition getDynamicLocal_v17_r73740(MethodDefinition method) {
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count; i++) {
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i = ConfuserUtils.findCallMethod(instrs, i, Code.Callvirt, "System.Byte System.IO.BinaryReader::ReadByte()");
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if (i < 0 || i + 5 >= instrs.Count)
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break;
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if (!DotNetUtils.isStloc(instrs[i + 1]))
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continue;
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var ldloc = instrs[i + 2];
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if (!DotNetUtils.isLdloc(ldloc))
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continue;
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if (!DotNetUtils.isLdloc(instrs[i + 3]))
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continue;
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var ldci4 = instrs[i + 4];
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if (!DotNetUtils.isLdcI4(ldci4) || DotNetUtils.getLdcI4Value(ldci4) != 0x7F)
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continue;
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if (instrs[i + 5].OpCode.Code != Code.And)
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continue;
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return DotNetUtils.getLocalVar(method.Body.Variables, ldloc);
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}
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return null;
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}
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static int getDynamicEndIndex_v17_r73740(MethodDefinition method, VariableDefinition local) {
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count - 5; i++) {
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int index = i;
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var stloc = instrs[index++];
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if (!DotNetUtils.isStloc(stloc) || DotNetUtils.getLocalVar(method.Body.Variables, stloc) != local)
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continue;
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if (!DotNetUtils.isLdloc(instrs[index++]))
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continue;
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if (instrs[index].OpCode.Code == Code.Call) {
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if (i + 7 >= instrs.Count)
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continue;
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index++;
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if (!DotNetUtils.isLdloc(instrs[index++]))
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continue;
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}
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if (!DotNetUtils.isLdloc(instrs[index++]))
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continue;
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var ldloc = instrs[index++];
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if (!DotNetUtils.isLdloc(ldloc) || DotNetUtils.getLocalVar(method.Body.Variables, ldloc) != local)
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continue;
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if (instrs[index++].OpCode.Code != Code.Conv_U1)
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continue;
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if (instrs[index++].OpCode.Code != Code.Stelem_I1)
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continue;
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return i;
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}
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return -1;
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}
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static int getDynamicEndIndex_v17_r74788(MethodDefinition method, VariableDefinition local) {
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count - 11; i++) {
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var stloc = instrs[i];
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if (!DotNetUtils.isStloc(stloc) || DotNetUtils.getLocalVar(method.Body.Variables, stloc) != local)
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continue;
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if (!DotNetUtils.isLdloc(instrs[i + 1]))
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continue;
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if (!DotNetUtils.isLdloc(instrs[i + 2]))
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continue;
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if (!DotNetUtils.isLdloc(instrs[i + 3]))
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continue;
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if (!DotNetUtils.isLdloc(instrs[i + 4]))
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continue;
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if (!DotNetUtils.isLdloc(instrs[i + 5]))
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continue;
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var ldci4 = instrs[i + 6];
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if (!DotNetUtils.isLdcI4(ldci4) || (DotNetUtils.getLdcI4Value(ldci4) != 8 && DotNetUtils.getLdcI4Value(ldci4) != 16))
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continue;
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if (instrs[i + 7].OpCode.Code != Code.Rem)
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continue;
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if (instrs[i + 8].OpCode.Code != Code.Ldelem_U1)
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continue;
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if (instrs[i + 9].OpCode.Code != Code.Xor)
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continue;
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if (instrs[i + 10].OpCode.Code != Code.Conv_U1)
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continue;
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if (instrs[i + 11].OpCode.Code != Code.Stelem_I1)
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continue;
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return i;
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}
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return -1;
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}
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static int getDynamicStartIndex_v17_r73740(MethodDefinition method, int endIndex) {
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if (endIndex < 0)
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return -1;
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var instrs = method.Body.Instructions;
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for (int i = endIndex; i >= 0; i--) {
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if (i == 0)
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return i == endIndex ? -1 : i + 1;
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if (instrs[i].OpCode.FlowControl == FlowControl.Next)
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continue;
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return i + 1;
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}
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return -1;
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}
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static readonly byte[] defaultDecryptKey_v17 = new byte[1];
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protected byte[] decryptConstant_v17_r73740_dynamic(DecrypterInfo info, byte[] encrypted, uint offs, uint key) {
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return decryptConstant_v17_r73740_dynamic(info, encrypted, offs, key, defaultDecryptKey_v17);
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}
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protected byte[] decryptConstant_v17_r73740_dynamic(DecrypterInfo info, byte[] encrypted, uint offs, uint key1, byte[] key2) {
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var local = getDynamicLocal_v17_r73740(info.decryptMethod);
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if (local == null)
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throw new ApplicationException("Could not find local");
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int endIndex = getDynamicEndIndex_v17_r73740(info.decryptMethod, local);
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if (endIndex < 0)
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endIndex = getDynamicEndIndex_v17_r74788(info.decryptMethod, local);
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int startIndex = getDynamicStartIndex_v17_r73740(info.decryptMethod, endIndex);
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if (startIndex < 0)
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throw new ApplicationException("Could not find start/end index");
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var constReader = new ConstantsReader(info.decryptMethod);
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return decrypt(encrypted, key1, (magic, i) => {
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constReader.setConstantInt32(local, magic);
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int index = startIndex, result;
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if (!constReader.getNextInt32(ref index, out result) || index != endIndex)
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throw new ApplicationException("Could not decrypt integer");
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return (byte)(result ^ key2[i % key2.Length]);
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});
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}
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protected byte[] decryptConstant_v17_r73764_native(DecrypterInfo info, byte[] encrypted, uint offs, uint key) {
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return decryptConstant_v17_r73764_native(info, encrypted, offs, key, defaultDecryptKey_v17);
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}
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protected byte[] decryptConstant_v17_r73764_native(DecrypterInfo info, byte[] encrypted, uint offs, uint key1, byte[] key2) {
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var x86Emu = new x86Emulator(new PeImage(fileData));
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return decrypt(encrypted, key1, (magic, i) => (byte)(x86Emu.emulate((uint)nativeMethod.RVA, magic) ^ key2[i % key2.Length]));
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}
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static byte[] decrypt(byte[] encrypted, uint key, Func<uint, int, byte> decryptFunc) {
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var reader = new BinaryReader(new MemoryStream(encrypted));
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var decrypted = new byte[reader.ReadInt32() ^ key];
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for (int i = 0; i < decrypted.Length; i++) {
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uint magic = Utils.readEncodedUInt32(reader);
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decrypted[i] = decryptFunc(magic, i);
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}
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return decrypted;
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}
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public object decryptInt32(MethodDefinition caller, MethodDefinition decryptMethod, object[] args) {
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var info = methodToDecrypterInfo.find(decryptMethod);
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byte typeCode;
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var data = decryptData(info, caller, args, out typeCode);
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if (typeCode != info.int32Type)
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return null;
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if (data.Length != 4)
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throw new ApplicationException("Invalid data length");
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return BitConverter.ToInt32(data, 0);
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}
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public object decryptInt64(MethodDefinition caller, MethodDefinition decryptMethod, object[] args) {
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var info = methodToDecrypterInfo.find(decryptMethod);
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byte typeCode;
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var data = decryptData(info, caller, args, out typeCode);
|
|
if (typeCode != info.int64Type)
|
|
return null;
|
|
if (data.Length != 8)
|
|
throw new ApplicationException("Invalid data length");
|
|
return BitConverter.ToInt64(data, 0);
|
|
}
|
|
|
|
public object decryptSingle(MethodDefinition caller, MethodDefinition decryptMethod, object[] args) {
|
|
var info = methodToDecrypterInfo.find(decryptMethod);
|
|
byte typeCode;
|
|
var data = decryptData(info, caller, args, out typeCode);
|
|
if (typeCode != info.singleType)
|
|
return null;
|
|
if (data.Length != 4)
|
|
throw new ApplicationException("Invalid data length");
|
|
return BitConverter.ToSingle(data, 0);
|
|
}
|
|
|
|
public object decryptDouble(MethodDefinition caller, MethodDefinition decryptMethod, object[] args) {
|
|
var info = methodToDecrypterInfo.find(decryptMethod);
|
|
byte typeCode;
|
|
var data = decryptData(info, caller, args, out typeCode);
|
|
if (typeCode != info.doubleType)
|
|
return null;
|
|
if (data.Length != 8)
|
|
throw new ApplicationException("Invalid data length");
|
|
return BitConverter.ToDouble(data, 0);
|
|
}
|
|
|
|
public string decryptString(MethodDefinition caller, MethodDefinition decryptMethod, object[] args) {
|
|
var info = methodToDecrypterInfo.find(decryptMethod);
|
|
byte typeCode;
|
|
var data = decryptData(info, caller, args, out typeCode);
|
|
if (typeCode != info.stringType)
|
|
return null;
|
|
return Encoding.UTF8.GetString(data);
|
|
}
|
|
|
|
protected abstract byte[] decryptData(DecrypterInfo info, MethodDefinition caller, object[] args, out byte typeCode);
|
|
}
|
|
}
|