加密后无法播放SD卡中的视频

Question

我正在使用加密制作一个安全的视频播放应用程序。在我的应用程序加密完成但它不能在我的VideoView中播放。没有显示错误。我希望当我点击该按钮时，视频将加密并保存在存储和播放中而不保存解密文件。但我无法做到这一点。请帮助我。告诉我我的代码中的问题在哪里。感谢

这是我的java代码

        encryptButton = (Button) findViewById(R.id.button);
        mVideoView = (VideoView) findViewById(R.id.vwVideo);
        mVideoView.setOnCompletionListener(this);
        encryptButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                try {
                    encrypt();
                } catch (Exception e) {
                    e.printStackTrace();
                }
                Toast.makeText(getApplicationContext(), " Encryption complete ",
                        Toast.LENGTH_SHORT).show();
            }
        });
        File file = new File(
                Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES),
                "/storage/emulated/0/DCIM/Camera/encrypt.mp4");

        mVideoView.setOnCompletionListener(this);
        mVideoView.setMediaController(new MediaController(this));
        try {
            mServer = new LocalSingleHttpServer();
            mServer.setCipher(myGetCipher());
            mServer.start();
            String path = mServer.getURL(file.getPath());
            mVideoView.setVideoPath(path);
            mVideoView.start();
        } catch (Exception e) {
            // Auto-generated catch block
            e.printStackTrace();
        }

    }

    private Cipher myGetCipher() throws NoSuchPaddingException, NoSuchAlgorithmException, NoSuchProviderException, InvalidKeyException {
        // avoid the default security provider "AndroidOpenSSL" in Android 4.3+ (http://libeasy.alwaysdata.net/network/#provider)
        Cipher c = Cipher.getInstance("ARC4", "BC");
        c.init(Cipher.DECRYPT_MODE, new SecretKeySpec("BrianIsInTheKitchen".getBytes(), "ARC4"));
        return c;
    }

    public static void encrypt() throws Exception {
        final byte[] buf = new byte[8192];
        final Cipher c = Cipher.getInstance("AES/CTR/NoPadding");
        c.init(Cipher.ENCRYPT_MODE, new SecretKeySpec("1234567890123456".getBytes(), "AES"), new IvParameterSpec(new byte[16]));
        final InputStream is = new FileInputStream("/storage/emulated/0/DCIM/Camera/VID_20140217_144346.mp4");
        final OutputStream os = new CipherOutputStream(new FileOutputStream("/storage/emulated/0/DCIM/Camera/encrypt.mp4"), c);
        while (true) {
            int n = is.read(buf);
            if (n == -1) break;
            os.write(buf, 0, n);
        }
        os.close();
        is.close();
    }

    @Override
    public void onCompletion(MediaPlayer mediaPlayer) {
        mServer.stop();
    }