131 lines
5.0 KiB
C#
131 lines
5.0 KiB
C#
using System;
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using System.IO;
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using System.Security.Cryptography;
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using System.Text;
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namespace AlicizaX
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{
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public static partial class Utility
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{
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/// <summary>
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/// 加密解密相关的实用函数。
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/// </summary>
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public static partial class Encryption
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{
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internal const int QuickEncryptLength = 220;
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/// <summary>
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/// 将 bytes 使用 code 做异或运算的快速版本。
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/// </summary>
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/// <param name="bytes">原始二进制流。</param>
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/// <param name="code">异或二进制流。</param>
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/// <returns>异或后的二进制流。</returns>
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public static byte[] GetQuickXorBytes(byte[] bytes, byte[] code)
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{
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return GetXorBytes(bytes, 0, QuickEncryptLength, code);
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}
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/// <summary>
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/// 将 bytes 使用 code 做异或运算的快速版本。此方法将复用并改写传入的 bytes 作为返回值，而不额外分配内存空间。
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/// </summary>
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/// <param name="bytes">原始及异或后的二进制流。</param>
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/// <param name="code">异或二进制流。</param>
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public static void GetQuickSelfXorBytes(byte[] bytes, byte[] code)
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{
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GetSelfXorBytes(bytes, 0, QuickEncryptLength, code);
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}
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/// <summary>
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/// 将 bytes 使用 code 做异或运算。
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/// </summary>
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/// <param name="bytes">原始二进制流。</param>
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/// <param name="code">异或二进制流。</param>
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/// <returns>异或后的二进制流。</returns>
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public static byte[] GetXorBytes(byte[] bytes, byte[] code)
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{
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if (bytes == null)
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{
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return null;
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}
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return GetXorBytes(bytes, 0, bytes.Length, code);
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}
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/// <summary>
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/// 将 bytes 使用 code 做异或运算。此方法将复用并改写传入的 bytes 作为返回值，而不额外分配内存空间。
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/// </summary>
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/// <param name="bytes">原始及异或后的二进制流。</param>
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/// <param name="code">异或二进制流。</param>
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public static void GetSelfXorBytes(byte[] bytes, byte[] code)
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{
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if (bytes == null)
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{
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return;
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}
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GetSelfXorBytes(bytes, 0, bytes.Length, code);
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}
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/// <summary>
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/// 将 bytes 使用 code 做异或运算。
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/// </summary>
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/// <param name="bytes">原始二进制流。</param>
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/// <param name="startIndex">异或计算的开始位置。</param>
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/// <param name="length">异或计算长度，若小于 0，则计算整个二进制流。</param>
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/// <param name="code">异或二进制流。</param>
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/// <returns>异或后的二进制流。</returns>
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public static byte[] GetXorBytes(byte[] bytes, int startIndex, int length, byte[] code)
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{
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if (bytes == null)
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{
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return null;
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}
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int bytesLength = bytes.Length;
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byte[] results = new byte[bytesLength];
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Array.Copy(bytes, 0, results, 0, bytesLength);
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GetSelfXorBytes(results, startIndex, length, code);
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return results;
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}
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/// <summary>
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/// 将 bytes 使用 code 做异或运算。此方法将复用并改写传入的 bytes 作为返回值，而不额外分配内存空间。
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/// </summary>
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/// <param name="bytes">原始及异或后的二进制流。</param>
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/// <param name="startIndex">异或计算的开始位置。</param>
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/// <param name="length">异或计算长度。</param>
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/// <param name="code">异或二进制流。</param>
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public static void GetSelfXorBytes(byte[] bytes, int startIndex, int length, byte[] code)
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{
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if (bytes == null)
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{
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return;
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}
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if (code == null)
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{
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throw new GameFrameworkException("Code is invalid.");
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}
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int codeLength = code.Length;
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if (codeLength <= 0)
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{
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throw new GameFrameworkException("Code length is invalid.");
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}
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if (startIndex < 0 || length < 0 || startIndex + length > bytes.Length)
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{
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throw new GameFrameworkException("Start index or length is invalid.");
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}
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int codeIndex = startIndex % codeLength;
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for (int i = startIndex; i < length; i++)
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{
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bytes[i] ^= code[codeIndex++];
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codeIndex %= codeLength;
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}
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}
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}
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}
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}
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