安卓 - 流无法正确读取数组

Question

我目前正在我的树莓派和我的安卓设备之间的连接。这种连接是用河豚加密的，似乎可以很好地处理较小的大小(通常低于1kb)。下一步，我试着从我的Pi发送一张图片到我的设备，这也应该是加密的。我的设备抛出了异常javax.crypto.BadPaddingException: pad block corrupted，经过一些调试后，我发现大约90%的传输数据被设置为零(用大小为2444368的数组进行测试，在位置212536之后，一切都为零)。

我的第一个猜测是，安卓不能分配足够的内存为我的数组，但没有例外告诉我，所以我告诉安卓，我的应用程序使用了很多ram通过largeHeap=true，这不是问题了。这可能是因为我不太了解Android是如何工作的，所以我想请您帮助我。有问题的部分(EncryptionUtil未显示，它不是问题的一部分):

客户端:

    public final byte[] readWithAppend() throws IOException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException, NoSuchAlgorithmException, NoSuchPaddingException{
    byte[] b = new byte[read()]; //works fine, tells me the size of the array
    System.out.println("Trying to read an array with the size " + b.length);
    in.read(b,0,b.length);//No Exception here, so allocation works
    if(b.length >= 10000){ //Just some debug for me to compare both sides, server and client.
        File f;
        FileOutputStream out = new FileOutputStream(f = new File(debugFile,EncryptionUtil.randomString(80)));
        System.out.println("PATH: " + f);
        out.write(b);out.close();
    }
    System.out.println("After position " + searchPos(b) + " everything is 0 ?!?!?");
    b = EncryptionUtil.decrypt(enc, b, sessionKey); //The Exception gets thrown here.
    return b;
}
private int searchPos(byte[] b){
    int pos = b.length;
    for(int i = b.length-1;i >= 0;i--){
        if(b[i] != 0)return pos;
        else pos--;
    }
    return pos;
}

服务端:

    private final void write(byte[] b,int off,int len,boolean appendLength) throws IOException{
    try {
        byte[] b2;
        if(len != b.length || off != 0){ //Just ignore this case
            byte[] buffer = new byte[len-off];System.arraycopy(b, off, buffer, 0, len);
            b2 = EncryptionUtil.encrypt(enc, buffer, sessionKey);
        }else{ //This is the case we have to look at
            b2 = EncryptionUtil.encrypt(enc, b, sessionKey);
            System.out.println("Sending an array with the size " + b2.length);
            System.out.println("Decrypting to check for mistakes");
            EncryptionUtil.decrypt(SymmetricEncryption.Blowfish, b2, sessionKey); //Debug.
            if(b2.length >= 10000){ //Again, debug to compare the both files
                FileOutputStream out2 = new FileOutputStream(new File("serverFile"));
                out2.write(b2);out2.close();
            }
        }
        if(appendLength)write(b2.length); //Works as well
        System.out.println("Length: " + b2.length + "; only writing: " + ((int)len/b.length)*b2.length);// it writes everything.
        out.write(b2,0,((int)len/b.length)*b2.length);  //The flush part happens somewhere else.
    } catch (InvalidKeyException | NoSuchAlgorithmException| NoSuchPaddingException | IllegalBlockSizeException| BadPaddingException e) {
        e.printStackTrace();
        //throw new IOException(e.getMessage());
    }
}

我知道这需要一些时间来工作到我的代码，但如果你能帮助我，我会很感激的。

编辑:关于EncryptionUtil的代码

  public static final byte[] encrypt(final SymmetricEncryption enc,final byte[] content,final SecretKey key) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException, UnsupportedEncodingException {
      final Cipher cipher = Cipher.getInstance(enc.toString());
      cipher.init(Cipher.ENCRYPT_MODE, key);
      return cipher.doFinal(content);
  }
  public static final byte[] decrypt(final SymmetricEncryption enc,final byte[] text,final SecretKey key) throws IllegalBlockSizeException, BadPaddingException, InvalidKeyException, NoSuchAlgorithmException, NoSuchPaddingException {
      final Cipher cipher = Cipher.getInstance(enc.toString());
      cipher.init(Cipher.DECRYPT_MODE, key);
      return cipher.doFinal(text);
  }

经过更多的测试，我发现我的树莓派不能正确地发送数据，所以我现在试着用块发送它。

Answer 1

我怀疑你的问题是对in.read的调用没有读取整个输入流。InputStream.read不能保证读取您所请求的整个长度。在while循环中读取输入流是相当正常的做法，读入缓冲区，直到到达流的末尾-更像:

byte[] buffer = new byte[1024];
int read;
while ((read = in.read(buffer)) != -1) {
    out.write(buffer, 0, read);
}
out.flush();
out.close();

请注意，您现有的代码没有检查in.read的返回值，以查看实际读取了多少字节。