t0WKExxd

1protected void EncryptAndroid() {
2    byte[] data = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
3            '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',};
4    byte[] header = {'a', 'b', 'c', 'd', 'a', 'b', 'c', 'd', 'a', 'b', 'c', 'd', 'a', 'b', 'c', 'd', 'a', 'b', 'c', 'd', 'a', 'b', 'c', 'd', 'a', 'b', 'c', 'd', 'a', 'b', 'c', 'd', 'a', 'b', 'c', 'd', 'a', 'b', 'c', 'd',
5            'a', 'b', 'c', 'd',};
6    byte[] updatedHeader = {'A', 'B', 'C', 'D', 'A', 'B', 'C', 'D', 'A', 'B', 'C', 'D', 'A', 'B', 'C', 'D', 'A', 'B', 'C', 'D', 'A', 'B', 'C', 'D', 'A', 'B', 'C', 'D', 'A', 'B', 'C', 'D',
7            'A', 'B', 'C', 'D', 'A', 'B', 'C', 'D', 'A', 'B', 'C', 'D'};
8    byte[] encryptedBytes = new byte[100];
9
10    try {
11        SecretKey secret = null;
12        // key generation using AndroidKeyStore provider
13        KeyGenerator keyGenerator = KeyGenerator.getInstance(KeyProperties.KEY_ALGORITHM_AES, "AndroidKeyStore");
14        keyGenerator.init(
15                    new KeyGenParameterSpec.Builder("key2",
16                            KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT)
17                            .setKeySize(256)
18                            .setBlockModes(KeyProperties.BLOCK_MODE_CTR)
19                            .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_NONE)
20                            .build());
21        secret = keyGenerator.generateKey();
22
23        // Cipher object initialization
24        Cipher cipher = Cipher.getInstance("AES/CTR/NoPadding");
25        cipher.init(Cipher.ENCRYPT_MODE, secret);
26
27        // Getting IV
28        AlgorithmParameters params = cipher.getParameters();
29        byte[] iv = params.getParameterSpec(IvParameterSpec.class).getIV();
30
31        RandomAccessFile fd = new RandomAccessFile(sdCard.getAbsolutePath() + "/Notes/sample.encrypted","rw");
32
33        int offset = 0;
34        encryptedBytes = cipher.doFinal(header, offset, 10);
35        fd.write(encryptedBytes);
36        encryptedBytes = cipher.doFinal(data, offset, 40);
37        fd.write(encryptedBytes);
38
39        FileOutputStream ivStream = new FileOutputStream(sdCard.getAbsolutePath() + "/Notes/iv.dat");
40        if (ivStream != null) {
41            Log.d("Encryption", "Writing iv data to output file");
42            ivStream.write(iv);
43        }
44
45        ivStream.close();
46        fd.close();
47    }catch (Exception e) {
48        e.printStackTrace();
49    }
50}