解密图像时，给出 javax.crypto.BadPaddingException: pa

时间：2023-02-26

本文介绍了解密图像时，给出 javax.crypto.BadPaddingException: pad block损坏的Android的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

您好，我是 android 和图像加密的新手.我的场景是这样的，

Hi i'm new to android and Image encryption. My scenario is like this,

首先我要加密图像文件.
那我上传到服务器
我正在从我的应用下载加密图像并将其保存在 SD 卡中.
然后我在将其设置为 imageView 之前对其进行解密

(我用过的所有需要方法见底部..)

(See bottom for all need methods I have used..)

但我得到 javax.crypto.BadPaddingException: 解密时垫块损坏.我读了一些关于这个例外的文章，但都是关于文本加密的.你能帮我避免这种情况吗?提前谢谢你

图像加密使用 ...

private byte[] encrypt(byte[] raw, byte[] clear) throws Exception
{
    SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
    byte[] encrypted = cipher.doFinal(clear);
    return encrypted;
}

这里我也保存了其他几张图片，都成功保存到了sd卡中...

Here I'm saving several other images as well, all saved in sd card successfully...

for (int i = 0; i < imageUrls.size(); i++)
                {
                    File file = new File(imageUrls.get(i));

                    String metapath = CommonUtils.getDataFromPreferences("metaPath", "");
                    Log.d("metapath", metapath);
                    String extStorageDirectory = metapath + file.getName();

                    File wallpaperDirectory = new File(extStorageDirectory);
                    if (!wallpaperDirectory.exists() || wallpaperDirectory.length() == 0)
                    {
                        new DownloadImagesTask()
                            .executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, imageUrls.get(i));
                    }
                }
                Toast toast = Toast.makeText(ScratchDetailsActivity.this, "Lottery was purchased and saved to sdcard/E-Lottery",
                    Toast.LENGTH_LONG);
                toast.setGravity(Gravity.CENTER, 0, 0);
                toast.show();

图像解密...

这里的解密文件第一个参数是密钥，第二个是我们从 SD 卡获取的加密文件.

decrypt the file here first argument is key and second is encrypted file which we get from SD card.

        decrpt = simpleCrypto.decrypt(KEY, getImageFileFromSdCard());
        bmpimg2 = BitmapFactory.decodeByteArray(decrpt, 0, decrpt.length);
        Drawable d = new BitmapDrawable(getResources(), bmpimg2);
        hiddenImage.setImageDrawable(d);

下载图像任务..

public class DownloadImagesTask extends AsyncTask<String, Void, InputStream>{
private String fileName;

@Override
protected InputStream doInBackground(String... urls)
{
    //Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
    return download_Image(urls[0]);
}

@Override
protected void onPostExecute(InputStream result)
{
    storeImage(result);

}

private InputStream download_Image(String url)
{
    InputStream is = null;
    File file = new File(url);
    fileName = file.getName();
    try
    {
        URL aURL = new URL(url);
        URLConnection conn = aURL.openConnection();
        conn.connect();
        is = conn.getInputStream();
    }
    catch (OutOfMemoryError e)
    {
        Log.e("Hub", "Error getting the image from server : " + e.getMessage().toString());
    }
    catch (IOException e)
    {
        Log.e("Hub", "Error getting the image from server : " + e.getMessage().toString());
    }

    return is;
}

public void storeImage(InputStream is)
{

    String extStorageDirectory = CommonUtils.getDataFromPreferences("metaPath", "");

    Log.d("extStorageDirectory", extStorageDirectory);
    OutputStream outStream = null;

    File wallpaperDirectory = new File(extStorageDirectory);
    if (!wallpaperDirectory.exists())
    {
        wallpaperDirectory.mkdirs();
    }
    File outputFile = new File(wallpaperDirectory, fileName);
    if (!outputFile.exists() || outputFile.length() == 0)
    {
        try
        {
            outStream = new FileOutputStream(outputFile);
        }
        catch (FileNotFoundException e1)
        {
            e1.printStackTrace();
        }

        try
        {
            int bytesRead = -1;
            byte[] buffer = new byte[4096];
            while ((bytesRead = is.read(buffer)) != -1)
            {
                outStream.write(buffer, 0, bytesRead);
            }

            outStream.close();
            is.close();
            Log.d("ScratchActivtiy", "Image Saved");

        }
        catch (FileNotFoundException e)
        {
            e.printStackTrace();

        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }
}}

getImageFileFromSDCard 方法

getImageFileFromSDCard method

/**
     * This method fetch encrypted file which is save in sd card and convert it in byte array after that this file will
     * be decrept.
     * 
     * @return byte array of encrypted data for decription.
     * @throws FileNotFoundException
     */

public byte[] getImageFileFromSdCard() throws FileNotFoundException
{

    byte[] inarry = null;

    try
    {
        String metapath = CommonUtils.getDataFromPreferences("metaPath", "");

        File imageFolder = new File(metapath);
        File urlFile = new File(selectedLottery.getImage());

        for (File f : imageFolder.listFiles())
        {
            if (urlFile.getName().equals(f.getName()))
                metapath = metapath + f.getName();
        }
        File imageFile = new File(metapath);
        //Convert file into array of bytes.
        FileInputStream fileInputStream = null;
        byte[] bFile = new byte[(int) imageFile.length()];
        fileInputStream = new FileInputStream(imageFile);
        fileInputStream.read(bFile);
        fileInputStream.close();
        inarry = bFile;

    }
    catch (IOException e)
    {
        Log.d("Exception", e.getMessage());
    }

    return inarry;
}

解密图像时，给出 javax.crypto.BadPaddingException: pa

问题描述

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