android - 如何在 ImageView 中加载 Cipher 加密图像文件而不保存到设备
问题描述
我正在创建一个具有内容安全性的应用程序,因为没有人可以复制内容和文件。我正在使用密码直接从 URL 加密图像,而无需下载到设备。请在下面找到我的代码。
URL url = new URL(images.getImageurl());
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setDoOutput(true);
File folder = new File(Environment.getExternalStorageDirectory(), "zerb");
boolean success = true;
if (!folder.exists()){
folder.mkdirs();
}
InputStream fis = connection.getInputStream();
String path = folder.getAbsolutePath() + "images.getImageName + ".jpg";
encryptfile(fis, path, AppConstants.password + images.getContentid() + images.getTopicid())
fis.close();
密码加密方法代码是
private static boolean encryptfile(InputStream inputStream, String path, String password) throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
FileOutputStream fos = new FileOutputStream(path.concat(".crypt"));
byte[] key = (AppConstants.salt + password).getBytes("UTF-8");
MessageDigest sha = MessageDigest.getInstance("SHA-1");
key = sha.digest(key);
key = Arrays.copyOf(key, 16);
SecretKeySpec sks = new SecretKeySpec(key, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, sks);
CipherOutputStream cos = new CipherOutputStream(fos, cipher);
int b;
byte[] d = new byte[8];
while ((b = inputStream.read(d)) != -1) {
cos.write(d, 0, b);
}
cos.flush();
cos.close();
inputStream.close();
File encryptedFile = new File(path.concat(".crypt"));
return (encryptedFile.exists());
}
并且解密代码是
public static void decrypt(String path, String password, String outPath) throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
FileInputStream fis = new FileInputStream(path);
FileOutputStream fos = new FileOutputStream(outPath);
byte[] key = (AppConstants.salt + password).getBytes("UTF-8");
MessageDigest sha = MessageDigest.getInstance("SHA-1");
key = sha.digest(key);
key = Arrays.copyOf(key, 16);
SecretKeySpec sks = new SecretKeySpec(key, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, sks);
CipherInputStream cis = new CipherInputStream(fis, cipher);
int b;
byte[] d = new byte[8];
while ((b = cis.read(d)) != -1) {
fos.write(d, 0, b);
}
fos.flush();
fos.close();
cis.close();
}
如果我解密图像,它将显示并可以从设备复制。我所需要的只是将加密的图像加载到 ImageView 而不将解密的图像保存到设备中,这样就没有人可以复制了。请有人帮助我。
解决方案
可以ImageView
显示android.graphics.Bitmap
可以直接从InputStream
.
例如,该decrypt()
方法可以适用于返回 a Bitmap
:
public Bitmap decrypt(String path, String password) throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
FileInputStream fis = new FileInputStream(path);
byte[] key = (AppConstants.salt + password).getBytes("UTF-8");
MessageDigest sha = MessageDigest.getInstance("SHA-1");
key = sha.digest(key);
key = Arrays.copyOf(key, 16);
SecretKeySpec sks = new SecretKeySpec(key, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, sks);
CipherInputStream cis = new CipherInputStream(fis, cipher);
Bitmap bitmap = BitmapFactory.decodeStream(cis);
cis.close();
return bitmap;
}
(虽然它被称为Bitmap
,但可以解码 a.jpg
或.png
)。
然后这可以显示在ImageView
:
ImageView imageView = findViewById(R.id.imageView);
Bitmap bitmap = decrypt(path + ".crypt", password);
imageView.setImageBitmap(bitmap);
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