Unity Bundle文件加密方式三：DES算法

上篇介绍了AES算法，本篇介绍类似原理的另外一种对称算法。关于该算法的详解，请移看他人博客https://blog.youkuaiyun.com/z784561257/article/details/78174106

DES算法封装实现如下：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.Security.Cryptography;
using System.Text;
using System.IO;
/*
 * Autohr:W
 * Des算法加密工具
 */
namespace W.GameFramework.HotUpdate
{
    public class DesEncryptHelper : EncryptionHelper
    {
        /// <summary>
        /// 文件解密
        /// </summary>
        /// <param name="encryptedFile"></param>
        /// <param name="key"></param>
        /// <returns></returns>
        public byte[] DeEncrypthFile(byte[] encryptedFile, string key)
        {
            byte[] originalFile = null;

            byte[] keyBytes = Encoding.UTF8.GetBytes(key);

            DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
            provider.Key = keyBytes;
            provider.IV = keyBytes;

            MemoryStream memoryStream = new MemoryStream();
            CryptoStream cryptoStream = new CryptoStream(memoryStream,provider.CreateDecryptor(),CryptoStreamMode.Write);
            cryptoStream.Write(encryptedFile, 0, encryptedFile.Length);
            cryptoStream.FlushFinalBlock();

            originalFile = memoryStream.ToArray();

            return originalFile;
        }


        /// <summary>
        /// 文件加密
        /// </summary>
        /// <param name="targetFile"></param>
        /// <param name="key"></param>
        /// <returns></returns>
        public byte[] EncryptFile(byte[] targetFile, string key)
        {
            byte[] encryptedFile = null;

            byte[] keyBytes = Encoding.UTF8.GetBytes(key);

            DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
            provider.Key = keyBytes;
            provider.IV = keyBytes;

            MemoryStream memoryStream = new MemoryStream();
            CryptoStream cryptoStream = new CryptoStream(memoryStream,provider.CreateEncryptor(),CryptoStreamMode.Write);
            cryptoStream.Write(targetFile, 0, targetFile.Length);
            cryptoStream.FlushFinalBlock();

            encryptedFile = memoryStream.ToArray();

            return encryptedFile;
        }
    }
}