ybFqJyLg

1package com.example.chernovik;
2
3
4import android.util.Base64;
5
6
7
8import javax.crypto.Cipher;
9import javax.crypto.spec.IvParameterSpec;
10import javax.crypto.spec.SecretKeySpec;
11
12
13
14
15public class AesCrypto {
16
17    String key = "0123456789abcdef"; // 128 bit key
18    String initVector = "abcdef9876543210"; // 16 bytes IV, it is recommended to use a different random IV for every message!
19
20    private static String CIPHER_NAME = "AES/CBC/PKCS5PADDING";
21    private static int CIPHER_KEY_LEN = 16; //128 bits
22
23    /**
24     * Encrypt data using AES Cipher (CBC) with 128 bit key
25     *
26     * @param key  - key to use should be 16 bytes long (128 bits)
27     * @param iv   - initialization vector
28     * @param data - data to encrypt
29     * @return encryptedData data in base64 encoding with iv attached at end after a :
30     */
31    public static String encrypt(String key, String iv, String data) {
32
33        try {
34            IvParameterSpec ivSpec = new IvParameterSpec(iv.getBytes("UTF-8"));
35            SecretKeySpec secretKey = new SecretKeySpec(fixKey(key).getBytes("UTF-8"), "AES");
36
37            Cipher cipher = Cipher.getInstance(AesCrypto.CIPHER_NAME);
38            cipher.init(Cipher.ENCRYPT_MODE, secretKey, ivSpec);
39
40            byte[] encryptedData = cipher.doFinal((data.getBytes()));
41
42            String encryptedDataInBase64 = Base64.getEncoder().encodeToString(encryptedData);
43            String ivInBase64 = Base64.getEncoder().encodeToString(iv.getBytes("UTF-8"));
44
45            return encryptedDataInBase64 + ":" + ivInBase64;
46
47        } catch (Exception ex) {
48            throw new RuntimeException(ex);
49        }
50    }
51
52    private static String fixKey(String key) {
53
54        if (key.length() < AesCrypto.CIPHER_KEY_LEN) {
55            int numPad = AesCrypto.CIPHER_KEY_LEN - key.length();
56
57            for (int i = 0; i < numPad; i++) {
58                key += "0"; //0 pad to len 16 bytes
59            }
60
61            return key;
62
63        }
64
65        if (key.length() > AesCrypto.CIPHER_KEY_LEN) {
66            return key.substring(0, CIPHER_KEY_LEN); //truncate to 16 bytes
67        }
68
69        return key;
70    }
71
72    /**
73     * Decrypt data using AES Cipher (CBC) with 128 bit key
74     *
75     * @param key  - key to use should be 16 bytes long (128 bits)
76     * @param data - encrypted data with iv at the end separate by :
77     * @return decrypted data string
78     */
79
80    public static String decrypt(String key, String data) {
81
82        try {
83            String[] parts = data.split(":");
84
85            IvParameterSpec iv = new IvParameterSpec(Base64.getDecoder().decode(parts[1]));
86            SecretKeySpec secretKey = new SecretKeySpec(key.getBytes("UTF-8"), "AES");
87
88            Cipher cipher = Cipher.getInstance(AesCrypto.CIPHER_NAME);
89            cipher.init(Cipher.DECRYPT_MODE, secretKey, iv);
90
91            byte[] decodedEncryptedData = Base64.getDecoder().decode(parts[0]);
92
93            byte[] original = cipher.doFinal(decodedEncryptedData);
94
95            return new String(original);
96        } catch (Exception ex) {
97            throw new RuntimeException(ex);
98        }
99    }
100}