obfuz/Runtime/EncryptorBase.cs

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// Copyright 2025 Code Philosophy
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
using System;
using System.Runtime.CompilerServices;
using System.Text;
using Unity.Collections.LowLevel.Unsafe;
using UnityEngine.Assertions;
namespace Obfuz
{
public abstract class EncryptorBase : IEncryptor
{
public abstract int OpCodeCount { get; }
public static int[] ConvertToIntKey(byte[] key)
{
Assert.AreEqual(0, key.Length % 4);
int align4Length = key.Length / 4;
int[] intKey = new int[align4Length];
Buffer.BlockCopy(key, 0, intKey, 0, key.Length);
return intKey;
}
public abstract int Encrypt(int value, int opts, int salt);
public abstract int Decrypt(int value, int opts, int salt);
public virtual long Encrypt(long value, int opts, int salt)
{
int low = (int)value;
int high = (int)(value >> 32);
int encryptedLow = Encrypt(low, opts, salt);
int encryptedHigh = Encrypt(high, opts, salt);
return ((long)encryptedHigh << 32) | (uint)encryptedLow;
}
public virtual long Decrypt(long value, int opts, int salt)
{
int low = (int)value;
int high = (int)(value >> 32);
int decryptedLow = Decrypt(low, opts, salt);
int decryptedHigh = Decrypt(high, opts, salt);
return ((long)decryptedHigh << 32) | (uint)decryptedLow;
}
public virtual unsafe float Encrypt(float value, int opts, int salt)
{
if (float.IsNaN(value) || float.IsInfinity(value))
{
return value;
}
ref int intValue = ref *(int*)&value;
int xorValue = ((1 << 23) - 1) & Decrypt(0xABCD, opts, salt);
intValue ^= xorValue;
return value;
}
public virtual unsafe float Decrypt(float value, int opts, int salt)
{
if (float.IsNaN(value) || float.IsInfinity(value))
{
return value;
}
ref int intValue = ref *(int*)&value;
int xorValue = ((1 << 23) - 1) & Decrypt(0xABCD, opts, salt);
intValue ^= xorValue;
return value;
}
public virtual unsafe double Encrypt(double value, int opts, int salt)
{
if (double.IsNaN(value) || double.IsInfinity(value))
{
return value;
}
ref long longValue = ref *(long*)&value;
long xorValue = ((1L << 52) - 1) & Decrypt(0xAABBCCDDL, opts, salt);
longValue ^= xorValue;
return value;
}
public virtual unsafe double Decrypt(double value, int opts, int salt)
{
if (double.IsNaN(value) || double.IsInfinity(value))
{
return value;
}
ref long longValue = ref *(long*)&value;
long xorValue = ((1L << 52) - 1) & Decrypt(0xAABBCCDDL, opts, salt);
longValue ^= xorValue;
return value;
}
public virtual unsafe byte[] Encrypt(byte[] value, int offset, int length, int ops, int salt)
{
if (length == 0)
{
return Array.Empty<byte>();
}
var encryptedBytes = new byte[length];
int intArrLength = length >> 2;
// align to 4
if ((offset & 0x3) != 0)
{
Buffer.BlockCopy(value, offset, encryptedBytes, 0, length);
// encrypt int
fixed (byte* dstBytePtr = &encryptedBytes[0])
{
int* dstIntPtr = (int*)dstBytePtr;
int last = 0;
for (int i = 0; i < intArrLength; i++)
{
last ^= Encrypt(dstIntPtr[i], ops, salt);
dstIntPtr[i] = last;
}
}
for (int i = intArrLength * 4; i < length; i++)
{
encryptedBytes[i] = (byte)(encryptedBytes[i] ^ salt);
}
}
else
{
// encrypt int
fixed (byte* srcBytePtr = &value[offset])
{
fixed (byte* dstBytePtr = &encryptedBytes[0])
{
int* srcIntPtr = (int*)srcBytePtr;
int* dstIntPtr = (int*)dstBytePtr;
int last = 0;
for (int i = 0; i < intArrLength; i++)
{
last ^= Encrypt(srcIntPtr[i], ops, salt);
dstIntPtr[i] = last;
}
}
}
for (int i = intArrLength * 4; i < length; i++)
{
encryptedBytes[i] = (byte)(value[offset + i] ^ salt);
}
}
return encryptedBytes;
}
public unsafe virtual byte[] Decrypt(byte[] value, int offset, int length, int ops, int salt)
{
if (length == 0)
{
return Array.Empty<byte>();
}
var decryptedBytes = new byte[length];
int intArrLength = length >> 2;
// align to 4
if ((offset & 0x3) != 0)
{
Buffer.BlockCopy(value, offset, decryptedBytes, 0, length);
// encrypt int
fixed (byte* dstBytePtr = &decryptedBytes[0])
{
int* dstIntPtr = (int*)dstBytePtr;
int last = 0;
for (int i = 0; i < intArrLength; i++)
{
int oldLast = last;
last = dstIntPtr[i];
dstIntPtr[i] = Decrypt(last ^ oldLast, ops, salt);
}
}
for (int i = intArrLength * 4; i < length; i++)
{
decryptedBytes[i] = (byte)(decryptedBytes[i] ^ salt);
}
}
else
{
// encrypt int
fixed (byte* srcBytePtr = &value[offset])
{
fixed (byte* dstBytePtr = &decryptedBytes[0])
{
int* srcIntPtr = (int*)srcBytePtr;
int* dstIntPtr = (int*)dstBytePtr;
int last = 0;
for (int i = 0; i < intArrLength; i++)
{
int oldLast = last;
last = srcIntPtr[i];
dstIntPtr[i] = Decrypt(last ^ oldLast, ops, salt);
}
}
}
for (int i = intArrLength * 4; i < length; i++)
{
decryptedBytes[i] = (byte)(value[offset + i] ^ salt);
}
}
return decryptedBytes;
}
public virtual byte[] Encrypt(string value, int ops, int salt)
{
if (value.Length == 0)
{
return Array.Empty<byte>();
}
byte[] bytes = Encoding.UTF8.GetBytes(value);
return Encrypt(bytes, 0, bytes.Length, ops, salt);
}
public virtual string DecryptString(byte[] value, int offset, int length, int ops, int salt)
{
if (length == 0)
{
return string.Empty;
}
byte[] bytes = Decrypt(value, offset, length, ops, salt);
return Encoding.UTF8.GetString(bytes);
}
public virtual unsafe void EncryptBlock(byte[] data, int ops, int salt)
{
int length = data.Length;
int intArrLength = length >> 2;
fixed (byte* dstBytePtr = &data[0])
{
int* dstIntPtr = (int*)dstBytePtr;
int last = 0;
for (int i = 0; i < intArrLength; i++)
{
last ^= Encrypt(dstIntPtr[i], ops, salt);
dstIntPtr[i] = last;
}
}
for (int i = intArrLength * 4; i < length; i++)
{
data[i] = (byte)(data[i] ^ salt);
}
}
public virtual unsafe void DecryptBlock(byte[] data, int ops, int salt)
{
fixed (byte* dataPtr = &data[0])
{
DecryptBlock(dataPtr, data.Length, ops, salt);
}
}
private unsafe void DecryptBlock(byte* data, int length, int ops, int salt)
{
int intArrLength = length >> 2;
int* dstIntPtr = (int*)data;
int last = 0;
for (int i = 0; i < intArrLength; i++)
{
int oldLast = last;
last = dstIntPtr[i];
dstIntPtr[i] = Decrypt(oldLast ^ last, ops, salt);
}
for (int i = intArrLength * 4; i < length; i++)
{
data[i] = (byte)(data[i] ^ salt);
}
}
public virtual unsafe void DecryptInitializeArray(System.Array arr, System.RuntimeFieldHandle field, int length, int ops, int salt)
{
//Assert.AreEqual(Marshal.SizeOf(arr.GetType().GetElementType()), arr.Length);
RuntimeHelpers.InitializeArray(arr, field);
if (arr is byte[] byteArr)
{
fixed (byte* dataPtr = &byteArr[0])
{
DecryptBlock(dataPtr, length, ops, salt);
}
}
else if (arr is int[] intArr)
{
fixed (int* dataPtr = &intArr[0])
{
DecryptBlock((byte*)dataPtr, length, ops, salt);
}
}
else if (arr is long[] longArr)
{
fixed (long* dataPtr = &longArr[0])
{
DecryptBlock((byte*)dataPtr, length, ops, salt);
}
}
else if (arr is sbyte[] sbyteArr)
{
fixed (sbyte* dataPtr = &sbyteArr[0])
{
DecryptBlock((byte*)dataPtr, length, ops, salt);
}
}
else if (arr is short[] shortArr)
{
fixed (short* dataPtr = &shortArr[0])
{
DecryptBlock((byte*)dataPtr, length, ops, salt);
}
}
else if (arr is ushort[] ushortArr)
{
fixed (ushort* dataPtr = &ushortArr[0])
{
DecryptBlock((byte*)dataPtr, length, ops, salt);
}
}
else if (arr is uint[] uintArr)
{
fixed (uint* dataPtr = &uintArr[0])
{
DecryptBlock((byte*)dataPtr, length, ops, salt);
}
}
else if (arr is ulong[] ulongArr)
{
fixed (ulong* dataPtr = &ulongArr[0])
{
DecryptBlock((byte*)dataPtr, length, ops, salt);
}
}
else if (arr is float[] floatArr)
{
fixed (float* dataPtr = &floatArr[0])
{
DecryptBlock((byte*)dataPtr, length, ops, salt);
}
}
else if (arr is double[] doubleArr)
{
fixed (double* dataPtr = &doubleArr[0])
{
DecryptBlock((byte*)dataPtr, length, ops, salt);
}
}
else
{
void* dataPtr = UnsafeUtility.PinGCArrayAndGetDataAddress(arr, out ulong handle);
try
{
DecryptBlock((byte*)dataPtr, length, ops, salt);
}
finally
{
UnsafeUtility.ReleaseGCObject(handle);
}
}
}
}
}