使用facebook隐藏解密文件时出现OutOfMemoryException

Question

我正在开发 android 应用程序，我需要将视频保存在 SD 卡中，它不能转移，这就是为什么我在需要时使用 Facebook Conceal 进行加密和解密的原因如果视频尺寸更小就完美了。

每当我尝试对 GenyMotion running 2.3.7 中不超过 10MB 的大型视频文件进行加密和解密时，它会崩溃并显示 OutOfMemoryException，这意味着我运行出局了分配给我的应用程序的堆内存无法处理但必须阻止。

尝试过：

Apache Common Utils IO 包
各种 IO 实用程序

Facebook Conceal : 解密时说

 You must read the entire stream to completion.
 The verification is done at the end of the stream.
 Thus not reading till the end of the stream will cause
 a security bug. For safety, you should not
 use any of the data until it's been fully read or throw
 away the data if an exception occurs.

我用Facebook Conceal调用加密解密的代码:

加密 :

public void startEncryption() {
    // Creates a new Crypto object with default implementations of
    // a key chain as well as native library.
    // Check for whether the crypto functionality is available
    // This might fail if android does not load libaries correctly.
    if (!crypto.isAvailable()) {
        return;
    }
    OutputStream fileStream;
    try {
        File mEncryptedFile = new File(mPlainFile.getPath().substring(0,
                mPlainFile.getPath().length() - 4)
                + "_encrypted"
                + mPlainFile.getPath().substring(
                        mPlainFile.getPath().length() - 4,
                        mPlainFile.getPath().length()));

        fileStream = new BufferedOutputStream(new FileOutputStream(
                mEncryptedFile));

        // Creates an output stream which encrypts the data as
        // it is written to it and writes it out to the file.
        OutputStream outputStream;
        outputStream = crypto.getCipherOutputStream(fileStream, entity);
        outputStream.write(FileUtils.readFileToByteArray(mPlainFile));
        // fileStream.flush();
        // fileStream.close();
        // outputStream.flush();
        // outputStream.close();
        // outputStream.flush();
        File mRenameTo = new File(mPlainFile.getPath());
        mPlainFile.delete();
        mEncryptedFile.renameTo(mRenameTo);
    } catch (FileNotFoundException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (CryptoInitializationException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (KeyChainException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

解密：

public String startDecryption() {
    // Get the file to which ciphertext has been written.
    try {
        FileInputStream fileStream = new FileInputStream(mPlainFile);

        // Creates an input stream which decrypts the data as
        // it is read from it.
        InputStream inputStream;
        inputStream = crypto.getCipherInputStream(fileStream, entity);

        ByteArrayOutputStream out = new ByteArrayOutputStream();
        // org.apache.commons.io.output.ByteArrayOutputStream out = new
        // org.apache.commons.io.output.ByteArrayOutputStream(1024);
        // Read into a byte array.
        // int read;
        // byte[] buffer = new byte[1024];
        // // You must read the entire stream to completion.
        // // The verification is done at the end of the stream.
        // // Thus not reading till the end of the stream will cause
        // // a security bug.
        // int i = 0;
        // while ((read = inputStream.read(buffer)) != -1) {
        // out.write(buffer, 0, read);
        // Log.i(TAG, "bytearrayoutputstream "+i++ + " "+read + " " +
        // buffer.length + " "+out.size());
        // }

        mDecryptedFile = new File(mPlainFile.getPath().substring(0,
                mPlainFile.getPath().length() - 4)
                + "_decrypted"
                + (mPlainFile.getPath().substring(mPlainFile.getPath()
                        .length() - 4, mPlainFile.getPath().length())));

        OutputStream outputStream = new FileOutputStream(mDecryptedFile);
        // IOUtils.copy(inputStream, outputStream);

        try {
            final byte[] buffer = new byte[1024];
            int read;

            while ((read = inputStream.read(buffer)) != -1)
                outputStream.write(buffer, 0, read);

            outputStream.flush();
        } catch (Exception e) {

        } finally {
            outputStream.close();
        }

        // out.writeTo(outputStream);
        // out.flush();
        // out.close();

        // fileStream.close();
        inputStream.close();
        // outputStream.flush();
        outputStream.close();
        return mDecryptedFile.getPath();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (CryptoInitializationException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (KeyChainException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return null;
}

是否有任何解决方案可以变通并加密和解密大型视频文件？

Answer 1

您似乎正在将整个文件读入一个字节数组。您应该做的是创建一个输入流并将其提供给加密引擎。

所以这个：

 outputStream.write(FileUtils.readFileToByteArray(mPlainFile));

应该看起来像你的解密循环。

BufferedInputStream  bis = new BufferedInputStream(mPlainFile);
InputStream inputStream = crypto.getCipherInputStream(
                             bis,
                             entity);
while ((read = inputStream.read(buffer)) != -1) {
   outputStream.write(buffer, 0, read);
}

不确定这是否是您最终得到的结果。我从文档中提取了加密解码。我认为这证实了他们的意图是说必须读取流直到结束。

Answer 2

正如 Bruce 在 Encryption 上强调的瓶颈导致 OutOfMemoryException 在 Decryption 时。所以这是我在加密和解密时正在执行的代码，不再导致 OutOfMemoryException.

加密：

fileStream = new BufferedOutputStream(new FileOutputStream(mEncryptedFile));
OutputStream outputStream;
outputStream = crypto.getCipherOutputStream(fileStream, entity);
int read;
byte[] buffer = new byte[1024];
BufferedInputStream  bis = new BufferedInputStream(newFileInputStream(mPlainFile));
while ((read = bis.read(buffer)) != -1) {
       outputStream.write(buffer, 0, read);
    }
outputStream.close();
bis.close();

解密：

InputStream inputStream;
inputStream = crypto.getCipherInputStream(fileStream, entity);
ByteArrayOutputStream out = new ByteArrayOutputStream();
OutputStream outputStream = new FileOutputStream(mDecryptedFile);
BufferedInputStream bis = new BufferedInputStream(inputStream);
int mRead;
byte[] mBuffer = new byte[1024];
while ((mRead = bis.read(mBuffer)) != -1) {
   outputStream.write(mBuffer, 0, mRead);
    }
bis.close();
out.writeTo(outputStream);
inputStream.close();
outputStream.close();
out.close();

使用facebook隐藏解密文件时出现OutOfMemoryException

OutOfMemoryException while decrypting file using facebook conceal

java

encryption

android

facebook

facebook-conceal