Question

我正在尝试使用对话框中的字符串值来加密文件。我已经能够使用AES以正常方式加密文件。该文件存储在SDCard上。但是当我从Dialog Box中获取一个值并将其用于加密时，我得到了大小为零字节的加密文件。这是我的代码：

    public class MainActivity extends Activity {

//@SuppressWarnings("unchecked")
private static final String TAG = "MyActivity";
@Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);       

     AlertDialog.Builder alert = new AlertDialog.Builder(this);

        alert.setTitle("Title");
        alert.setMessage("Message");

        // Set an EditText view to get user input 
        final EditText input = new EditText(this);
        alert.setView(input);

        alert.setPositiveButton("Ok", new
      DialogInterface.OnClickListener()   {
        public void onClick(DialogInterface dialog, int whichButton) {
        String value = input.getText().toString();
        try {
                encrypt(value);
            } catch (InvalidKeyException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (NoSuchAlgorithmException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (NoSuchPaddingException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }});

        alert.setNegativeButton("Cancel", new
                   DialogInterface.OnClickListener() {
             public void onClick(DialogInterface dialog, int
          whichButton) {
                 // Canceled.
            }
            });

             alert.show();  }               
    static void encrypt(String Value) throws IOException,
       NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {

    final String libPath = Environment.getExternalStorageDirectory() + "/shoaib.jar";
    // Here you read the cleartext.
    FileInputStream fis = new FileInputStream(libPath);
    // This stream write the encrypted text. 
    FileOutputStream fos = new 
    FileOutputStream(Environment.getExternalStorageDirectory() + "/encrypted.jar");

    // Length is 16 byte
    SecretKeySpec sks = new SecretKeySpec(Value.getBytes(), "AES");
    Log.d(TAG,Value);
    // Create cipher
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.ENCRYPT_MODE, sks);
    // Wrap the output stream
    CipherOutputStream cos = new CipherOutputStream(fos, cipher);
    // Write bytes
    int b;
    byte[] d = new byte[8];
    while((b = fis.read(d)) != -1) {
        cos.write(d, 0, b);
    }
    // Flush and close streams.
    cos.flush();
    cos.close();
    fis.close();
    }

现在有人可以告诉我哪里出错了。

提前致谢：）

Answer 1

试试这段代码，

public static String Encrypt(String text, String key)
    {
        String Encoded = "";
        try {

            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
            byte[] keyBytes = new byte[16];
            byte[] b = key.getBytes("UTF-8");
            int len = b.length;
            if (len > keyBytes.length)
            {
                len = keyBytes.length;
            }
            System.arraycopy(b, 0, keyBytes, 0, len);
            SecretKeySpec keySpec = new SecretKeySpec(keyBytes, "AES");
            //IvParameterSpec ivSpec = new IvParameterSpec(keyBytes);
            final byte[] iv = new byte[16];
            Arrays.fill(iv, (byte) 0x00);
            IvParameterSpec ivSpec = new IvParameterSpec(iv);
            cipher.init(Cipher.ENCRYPT_MODE, keySpec,ivSpec);
            byte[] results = cipher.doFinal(text.getBytes("UTF-8"));
            Encoded = Base64.encodeToString(results,Base64.URL_SAFE);

        } catch (NoSuchAlgorithmException e) {
            Log.v(TAG, e.getMessage());
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            Log.v(TAG, e.getMessage());
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            Log.v(TAG, e.getMessage());
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            Log.v(TAG, e.getMessage());
            e.printStackTrace();
        } catch (BadPaddingException e) {
            Log.v(TAG, e.getMessage());
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            Log.v(TAG, e.getMessage());
            e.printStackTrace();
        } catch (InvalidAlgorithmParameterException e) {
            Log.v(TAG, e.getMessage());
            e.printStackTrace();
        }
        return Encoded;
    }

Answer 2

我使用这个课程：DesEncrypter。

在我的代码中：

    String STR = "sIwDraAEhBsRaKXMcvgW6jiRV+6FK11LbbFrAqLrc9qlJqCVhExyQg==";
    String key = "yourkey"
    DesEncrypter encrypter = new DesEncrypter(key);

    String decryptedStr = encrypter.decrypt(STR));
    String encrypteddStr = encrypter.encrypt(decryptedStr));

OR：

    String STR = "Hello world!";
    String key = "yourkey"
    DesEncrypter encrypter = new DesEncrypter(key);

    String encrypteddStr = encrypter.encrypt(STR));

使用对话框中的字符串值加密文件

2 个答案: