加密：

在自定义的PostProcessBundles方法中，对复制到ServerData的bundle进行读取，然后加密后写入覆盖。

//加密
byte[] datas = File.ReadAllBytes(targetPath);
File.WriteAllBytes(targetPath, AES.AESEncrypt(datas, KEY));

解密：

在自定义的AssetBundleProvider中的BeginOperation，所有的bundle的加载都先拿到byte数组先，不能直接用AssetBundle.LoadFromFile什么的了。

第三个网络下载的，后面会走第二个缓存bundle的逻辑。

private void BeginOperation()
{
    string path = m_ProvideHandle.Location.InternalId;
    var url = m_ProvideHandle.ResourceManager.TransformInternalId(m_ProvideHandle.Location);
    string bundleName = Path.GetFileName(url);
    // if a path starts with jar:file, it is an android embeded resource. The resource is a local file but cannot be accessed by 
    // FileStream(called in LoadWithDataProc) directly
    // Need to use webrequest's async call to get the content.
    if (AssetBundleManager.Instance.buildInData != null && AssetBundleManager.Instance.buildInData.BuildInBundleNames.Contains(bundleName))//本地资源
    {
        string streamPath = UnityEngine.AddressableAssets.Addressables.RuntimePath + "/" + PlatformMappingService.GetPlatformPathSubFolder() + "/" + bundleName;
        Debug.Log("LoadOne:" + streamPath);
        var crc = m_Options == null ? 0 : m_Options.Crc;
        var req = CreateWebRequest(streamPath);
        req.disposeDownloadHandlerOnDispose = false;
        m_WebRequestQueueOperation = WebRequestQueue.QueueRequest(req);
        if (m_WebRequestQueueOperation.IsDone)
        {
            m_RequestOperation = m_WebRequestQueueOperation.Result;
            m_RequestOperation.completed += StreamWebRequestOperationCompleted;
        }
        else
        {
            m_WebRequestQueueOperation.OnComplete += asyncOp =>
            {
                m_RequestOperation = asyncOp;
                m_RequestOperation.completed += StreamWebRequestOperationCompleted;
            };
        }
    }
    else if (AssetBundleManager.Instance.IsCache(bundleName))
    {
        string cachePath = Path.Combine(AssetBundleManager.Instance.GetBundleCachePath(), bundleName);
        Debug.Log("LoadTwo:" + cachePath);
        var crc = m_Options == null ? 0 : m_Options.Crc;
        m_RequestOperation = AssetBundle.LoadFromMemoryAsync(AES.AESDecrypt(File.ReadAllBytes(cachePath), AES.GenBundleKey()));
        m_RequestOperation.completed += LocalRequestOperationCompleted;
    }
    else if (ResourceManagerConfig.ShouldPathUseWebRequest(path))
    {
        Debug.Log("DownloadThree：" + url);
        var req = CreateWebRequest(m_ProvideHandle.Location);
        req.disposeDownloadHandlerOnDispose = false;
        m_WebRequestQueueOperation = WebRequestQueue.QueueRequest(req);
        if (m_WebRequestQueueOperation.IsDone)
        {
            m_RequestOperation = m_WebRequestQueueOperation.Result;
            m_RequestOperation.completed += WebRequestOperationCompleted;
        }
        else
        {
            m_WebRequestQueueOperation.OnComplete += asyncOp =>
            {
                m_RequestOperation = asyncOp;
                m_RequestOperation.completed += WebRequestOperationCompleted;
            };
        }
    }
    else
    {
        m_RequestOperation = null;
        m_ProvideHandle.Complete<MyAssetBundleResource>(null, false, new Exception(string.Format("Invalid path in AssetBundleProvider: '{0}'.", path)));
    }
}

private void StreamWebRequestOperationCompleted(AsyncOperation op)
{
    UnityWebRequestAsyncOperation remoteReq = op as UnityWebRequestAsyncOperation;
    var webReq = remoteReq.webRequest;
    if (!UnityWebRequestUtilities.RequestHasErrors(webReq, out UnityWebRequestResult uwrResult))
    {
        m_downloadHandler = webReq.downloadHandler;
        CompleteBundleLoad(AssetBundle.LoadFromMemory(AES.AESDecrypt(m_downloadHandler.data, KEY)));
    }
    webReq.Dispose();
}