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1public class AesCipher {
2
3    private static final String INIT_VECTOR = "ItIsOurBigSecret";
4
5    // зашифрование
6    static byte[] encrypt(byte[] secretKey, byte[] plainText, String mode) {
7
8        try {
9            if (!isKeyLengthValid(secretKey)) {
10                throw new Exception("Длина ключа должна быть 128, 192 или 256 бит!");
11            }
12
13            IvParameterSpec ivParameterSpec = new IvParameterSpec(INIT_VECTOR.getBytes());
14            SecretKeySpec secretKeySpec = new SecretKeySpec(secretKey, "AES");
15
16            Cipher cipher = Cipher.getInstance("AES/" + mode + "/PKCS5Padding");
17            if (mode.equals("ECB"))
18                cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
19            else
20                cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, ivParameterSpec);
21
22            return cipher.doFinal(plainText);
23        } catch (Throwable cause) {
24            System.out.print(cause.getMessage());
25        }
26
27        return null;
28    }
29
30
31    // дешифрование
32    static byte[] decrypt(byte[] secretKey, byte[] cipherText, String mode) {
33
34        try {
35            if (!isKeyLengthValid(secretKey)) {
36                throw new Exception("Длина ключа должна быть 128, 192 или 256 бит!");
37            }
38
39            IvParameterSpec ivParameterSpec = new IvParameterSpec(INIT_VECTOR.getBytes());
40            SecretKeySpec secretKeySpec = new SecretKeySpec(secretKey, "AES");
41
42            Cipher cipher = Cipher.getInstance("AES/" + mode + "/PKCS5Padding");
43            if (mode.equals("ECB"))
44                cipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
45            else
46                cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, ivParameterSpec);
47
48            return cipher.doFinal(cipherText);
49        } catch (Throwable cause) {
50            System.out.print(cause.getMessage());
51            Controller.ShowMessage(cause.getMessage());
52        }
53
54        return null;
55    }
56
57
58    // проверка длины ключа
59    private static boolean isKeyLengthValid(byte[] key) {
60        return key.length == 16 || key.length == 24 || key.length == 32;
61    }