VUDcvBvC

1    void encryptToken(String token) throws KeyStoreException, CertificateException, IOException, NoSuchAlgorithmException, NoSuchProviderException, InvalidAlgorithmParameterException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
2
3        final KeyGenerator keyGenerator = KeyGenerator.getInstance(KeyProperties.KEY_ALGORITHM_AES, "AndroidKeyStore");
4        final KeyGenParameterSpec keyGenParameterSpec = new KeyGenParameterSpec.Builder("MyKeyAlias",
5                KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT)
6                .setBlockModes(KeyProperties.BLOCK_MODE_GCM)
7                .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_NONE)
8                .build();
9        keyGenerator.init(keyGenParameterSpec);
10        SecretKey secretKey = keyGenerator.generateKey();
11
12        final Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
13        cipher.init(Cipher.ENCRYPT_MODE, secretKey);
14        iv = cipher.getIV();
15        encryption = cipher.doFinal(token.getBytes(StandardCharsets.UTF_8));
16    }
17
18    void decryptToken(String secretMessage) throws KeyStoreException, CertificateException, IOException, NoSuchAlgorithmException, UnrecoverableEntryException, NoSuchPaddingException, InvalidAlgorithmParameterException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
19        KeyStore keyStore = KeyStore.getInstance("AndroidKeyStore");
20        keyStore.load(null);
21        final KeyStore.SecretKeyEntry secretKeyEntry = (KeyStore.SecretKeyEntry) keyStore.getEntry("MyKeyAlias", null);
22        final SecretKey secretKey = secretKeyEntry.getSecretKey();
23
24        final Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
25        final GCMParameterSpec spec = new GCMParameterSpec(128, iv);
26        cipher.init(Cipher.DECRYPT_MODE, secretKey, spec);
27        final byte[] decodedData = cipher.doFinal(encryption);
28        final String unencryptedString = new String(decodedData, StandardCharsets.UTF_8);
29    }