Question

我正在处理Raspberry Pi与Android设备之间的连接。此连接使用blowfish加密，并且似乎可以在较小的尺寸（通常低于1 kB）下正常工作。在下一步中，我尝试将我的Pi中的图片发送到我的设备，该设备应该加密。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％的传输数据设置为零（使用大小为2444368的数组进行测试，在位置212536之后，一切都为零）。 / p>

我的第一个猜测是，Android无法为我的阵列分配足够的内存，但因为没有异常告诉我这样，在我告诉Android我的应用程序通过largeHeap=true使用了很多内存后，这不是问题了。可能是我对Android的运作方式不太了解，所以我想请你帮我解决。有问题的部分（EncryptionUtil未显示，它不是问题的一部分）：

客户方：

    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;
}

Serverside：

    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());
    }
}

我知道需要一些时间来处理我的代码，但如果你能帮助我，我会很感激。

编辑：有关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);
  }

经过一些测试后，我发现我的覆盆子Pi没有正确发送数据，所以我现在试图用块发送它。

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并非保证能够阅读您要求的全部长度。在while循环中读取输入流是非常正常的做法，读入缓冲区直到到达流的末尾 - 更像是：

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，您现有的代码不会检查in.read的返回值，以查看实际读取的字节数。

Android - Stream无法正确读取数组

1 个答案: