下载时加密音频 mp3 文件，在 android 中播放时解密

Question

我有一个 android 应用程序可以下载和播放 mp3 文件。但我想在下载时加密音频文件，然后解密播放。我已经在互联网上到处检查但没有找到任何解决方案。谁能帮我如何在下载时加密音频文件然后在播放时解密这是我下载文件的代码

     private void download() {
    if (Constant.arrayList_play.size() > 0) {

        File root = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/Myapp/cache");
        if (!root.exists()) {
            root.mkdirs();
        }

        File file = new File(root, Constant.arrayList_play.get(viewpager.getCurrentItem()).getMp3Name() + ".mp3");

        if (!file.exists()) {

            String url = Constant.arrayList_play.get(viewpager.getCurrentItem()).getMp3Url();
            DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
            request.setDescription(getResources().getString(R.string.downloading) + " - " + Constant.arrayList_play.get(viewpager.getCurrentItem()).getMp3Name());
            request.setTitle(Constant.arrayList_play.get(viewpager.getCurrentItem()).getMp3Name());
            request.allowScanningByMediaScanner();
            request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
            request.setDestinationUri(Uri.parse("file://" + Environment.getExternalStorageDirectory().getAbsolutePath() + "/Myapp/cache/" + Constant.arrayList_play.get(viewpager.getCurrentItem()).getMp3Name() + ".mp3"));
            DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
            manager.enqueue(request);

            new AsyncTask<String, String, String>() {
                @Override
                protected String doInBackground(String... strings) {
                    String json = JsonUtils.getJSONString(Constant.URL_DOWNLOAD_COUNT + Constant.arrayList_play.get(viewpager.getCurrentItem()).getId());
                    Log.e("aaa - ", json);
                    return null;
                }
            }.execute();
            Toast.makeText(MainActivity.this, getResources().getString(R.string.downloading), Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(MainActivity.this, getResources().getString(R.string.already_download), Toast.LENGTH_SHORT).show();
        }
    } else {
        Toast.makeText(MainActivity.this, getResources().getString(R.string.no_song_selected), Toast.LENGTH_SHORT).show();
    }
}

那么你能帮我一个代码吗？

Answer 1

我已经找到了我的问题的解决方案，并且已经在我的应用程序中使用了很多天，没有任何问题，所以我认为最好回答我自己的问题，因为许多用户在评论中要求解决方案。所以只需遵循以下代码-

  //Downloading and encrypting the audio

  AesCipherDataSink encryptingDataSink = new AesCipherDataSink(
      Util.getUtf8Bytes("4J95qN8RxBP8hTpk"),
      new DataSink() {
       private FileOutputStream fileOutputStream;

       @Override
       public void open(DataSpec dataSpec) throws IOException {
               fileOutputStream = new FileOutputStream(file);
        }

       @Override
       public void write(byte[] buffer, int offset, int length) throws IOException {
          fileOutputStream.write(buffer, offset, length);
        }

       @Override
       public void close() throws IOException {
             fileOutputStream.close();
         }
        });

   // Push the data through the sink, and close everything.
   encryptingDataSink.open(new DataSpec(Uri.fromFile(file)));
   URL downloadURL = new URL(strings[0]);
   HttpURLConnection connection = (HttpURLConnection) downloadURL.openConnection();
   connection.setChunkedStreamingMode(0);
   connection.setDoInput(true);
   connection.connect();
   if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) {
      return "Server error";
   }

   InputStream inputStream = connection.getInputStream();
   byte[] buffer = new byte[1024];
   int newLength;
   while ((newLength = inputStream.read(buffer)) > 0) {
        encryptingDataSink.write(buffer, 0, newLength);
    }
   encryptingDataSink.close();
   inputStream.close();



   //decrypting and playing the audio
   DataSource.Factory factory =
                new CustomDataSourceFactory(
                        context,
                        new OkHttpDataSourceFactory(new OkHttpClient(), Util.getUserAgent(context,
                              context.getResources().getString(R.string.app_name)))
                );

    MediaSource videoSource =
                new ProgressiveMediaSource.Factory(factory)
                        .createMediaSource(Uri.parse(tempFile.getAbsolutePath()));
    exoPlayer.addMediaSource(videoSource);

    
   //CustomDataSourceFactoryClass

    public class CustomDataSourceFactory implements DataSource.Factory {

      private final Context context;
      private final DataSource.Factory baseDataSourceFactory;


      public CustomDataSourceFactory(Context context, DataSource.Factory baseDataSourceFactory) {
        this.context = context.getApplicationContext();
        this.baseDataSourceFactory = baseDataSourceFactory;
       }

       @Override
        public DataSource createDataSource() {
         return new CryptedDefaultDataSource(context, baseDataSourceFactory.createDataSource());
         }
      }

   //CryptedDafaultDataSource
    public class CryptedDefaultDataSource implements DataSource {

      private final List<TransferListener> transferListeners;
      private final DataSource baseDataSource;
      private @Nullable
      DataSource fileDataSource,aesCipherDataSource,dataSource;
      private Context context;

      CryptedDefaultDataSource(Context context, DataSource baseDataSource) {
         this.context=context;
         this.baseDataSource = Assertions.checkNotNull(baseDataSource);
         transferListeners = new ArrayList<>();
      }

      @Override
      public void addTransferListener(TransferListener transferListener) {
       baseDataSource.addTransferListener(transferListener);
       transferListeners.add(transferListener);
       maybeAddListenerToDataSource(fileDataSource, transferListener);
       maybeAddListenerToDataSource(aesCipherDataSource, transferListener);
      }

     @Override
     public long open(DataSpec dataSpec) throws IOException {
        Assertions.checkState(dataSource == null);
        if (Util.isLocalFileUri(dataSpec.uri)) {
          dataSource = getCryptedDataSource(getFileDataSource());
        } else {
          dataSource = getCryptedDataSource(baseDataSource);
        }
       return dataSource.open(dataSpec);
      }

     @Override
      public int read(byte[] buffer, int offset, int readLength) throws IOException {
         return Assertions.checkNotNull(dataSource).read(buffer, offset, readLength);
       }

      @Nullable
      @Override
       public Uri getUri() {
        return dataSource == null ? null : dataSource.getUri();
      }

      @Override
      public Map<String, List<String>> getResponseHeaders() {
          return dataSource == null
            ? DataSource.super.getResponseHeaders()
            : dataSource.getResponseHeaders();
       }

     @Override
     public void close() throws IOException {
       if (dataSource != null) {
        try {
            dataSource.close();
        } finally {
            dataSource = null;
        }
      }
     }

    private DataSource getFileDataSource() {
      if (fileDataSource == null) {
         fileDataSource = new FileDataSource();
         addListenersToDataSource(fileDataSource);
       }
       return fileDataSource;
     }

    private DataSource getCryptedDataSource(DataSource upstreamDataSource) {
      if (aesCipherDataSource == null) {
        aesCipherDataSource = new AesCipherDataSource("4J95qN8RxBP8hTpk".getBytes(),upstreamDataSource);
        addListenersToDataSource(aesCipherDataSource);
      }
      return aesCipherDataSource;
     }

   private void addListenersToDataSource(DataSource dataSource) {
     for (int i = 0; i < transferListeners.size(); i++) {
        dataSource.addTransferListener(transferListeners.get(i));
     }
   }

     private void maybeAddListenerToDataSource(
        @Nullable DataSource dataSource, TransferListener listener) {
      if (dataSource != null) {
        dataSource.addTransferListener(listener);
      }
     }
   }

下载时加密音频 mp3 文件，在 android 中播放时解密

Encrypt audio mp3 file while downloading and decrypt it while playing in android

java

encryption

audio

mp3

download