Unity | AssetBundle资源包的加密与解密（恺撒加密）

一、创建预制体：用Sphere与Cube临时创建了一个物体，就叫Sphere吧；

二、将这个预制体Sphere打包成assetbundle包，具体介绍可点击这里进行参考（是我之前写的文章）；

1. 选中Sphere预制体，设置AssetBundle名称为myab；
2. 点击Unity菜单栏AssetBundle/AssetBundle_Window按钮。附上本次打AB包的相关代码（此代码需要放在Editor文件夹下）：

    [MenuItem("AssetBundle/AssetBundle_Window")]
    public static void BuildAssetToWindow()
    {
        string outPath = Application.dataPath + "/../BuildAssetBundle/Window/";
        CreateDir(outPath);
        BuildPipeline.BuildAssetBundles(outPath,BuildAssetBundleOptions.ForceRebuildAssetBundle, BuildTarget.StandaloneWindows);
        AssetDatabase.Refresh();
    }
    public static void CreateDir(string path)
    {
        DirectoryInfo info = new DirectoryInfo(path);
        if (!info.Exists)
        {
            info.Create();
        }
    }

3. 打包好的 AB包如下图所示：

 三、对myab资源进行加密（此处用的是恺撒加密），加密后的AB包为myab_Encryption.assetbundle（后缀名可写可不写）：

    private IEnumerator EncryptionAB()
    {
        WWW www = new WWW("file:///D:\\fcj\\unity2018\\VuforiaStudy\\BuildAssetBundle\\Window\\myab");
        yield return www;
        if (www.isDone)
        {
            if (www.error == null)
            {
                byte[] bytes = www.bytes;
                for (int i = 0; i < bytes.Length; i++)//恺撒加密
                {
                    bytes[i] += 1;
                }
                File.WriteAllBytes("D:\\fcj\\unity2018\\VuforiaStudy\\BuildAssetBundle\\Window\\myab_Encryption.assetbundle", bytes);
            }
        }
    }

四、 解密并实例化被加密后的AB包：

    private IEnumerator DecryptAB()
    {
        WWW www = new WWW("file:///D:\\fcj\\unity2018\\VuforiaStudy\\BuildAssetBundle\\Window\\myab_Encryption.assetbundle");
        yield return www;
        if (www.isDone)
        {
            if (www.error == null)
            {
                byte[] bytes = www.bytes;
                for (int i = 0; i < bytes.Length; i++)//恺撒解密
                {
                    bytes[i] -= 1;
                }
                AssetBundle ab = AssetBundle.LoadFromMemory(bytes);
                GameObject go = ab.LoadAsset("Sphere") as GameObject;//注意这里是预制体名字
                Instantiate(go, Vector3.zero, Quaternion.identity);
                ab.Unload(false);
            }
        }
    }

五、AES加密：https://blog.csdn.net/weixin_39766005/article/details/103990313