QD3sarxu

1private static String salt;
2private static int iterations = 65536  ;
3private static int keySize = 256;
4private static byte[] ivBytes;
5private static String encodedKey = "jnf3guertsiAqwecdh7azitonderhascrui5godferh";
6private static SecretKey secretKey;
7public static int checkFlag = 0;
8
9public static String generateKey() throws Exception { //code for generating key
10
11    char[] chars = "abcdefghijklmnopqrstuvwxyzQWERTYUIOPLKJHGFDSAZXCVBNM1234567890".toCharArray();
12    StringBuilder sb = new StringBuilder();
13    Random random = new Random();
14    for (int i = 0; i < 20; i++) {
15        char c = chars[random.nextInt(chars.length)];
16        sb.append(c);
17    }
18    String output = sb.toString();
19    char[] plaintext = output.toCharArray();
20
21     salt = getSalt();
22     byte[] saltBytes = salt.getBytes();
23
24     SecretKeyFactory skf = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
25     PBEKeySpec spec = new PBEKeySpec(plaintext, saltBytes, iterations, keySize);
26     secretKey = skf.generateSecret(spec);
27
28     String newkey = Base64.getEncoder().encodeToString(secretKey.getEncoded());
29     return newkey;
30
31}
32
33public static String encrypt(char[] plaintext, String theKey) throws Exception { //code for encrypting
34
35    byte[] decodedKey = Base64.getDecoder().decode(theKey);
36
37    secretKey = new SecretKeySpec(decodedKey, 0, decodedKey.length, "AES"); 
38
39    SecretKeySpec secretSpec = new SecretKeySpec(secretKey.getEncoded(), "AES");
40
41    Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
42    cipher.init(Cipher.ENCRYPT_MODE, secretSpec);
43    AlgorithmParameters params = cipher.getParameters();
44    if(checkFlag == 0){
45        ivBytes = params.getParameterSpec(IvParameterSpec.class).getIV();
46        checkFlag = 1;
47    }
48    byte[] encryptedTextBytes = cipher.doFinal(String.valueOf(plaintext).getBytes("UTF-8"));
49
50    return DatatypeConverter.printBase64Binary(encryptedTextBytes);
51}
52
53public static String decrypt(char[] encryptedText, String theKey) throws Exception { //code for decrypting
54    salt = getSalt();
55
56
57    byte[] encryptedTextBytes = DatatypeConverter.parseBase64Binary(new String(encryptedText));
58    byte[] decodedKey = Base64.getDecoder().decode(theKey);
59    secretKey = new SecretKeySpec(decodedKey, 0, decodedKey.length, "AES"); 
60    SecretKeySpec secretSpec = new SecretKeySpec(secretKey.getEncoded(), "AES");
61
62    Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
63    cipher.init(Cipher.DECRYPT_MODE, secretSpec, new IvParameterSpec(ivBytes));
64
65    byte[] decryptedTextBytes = null;
66
67    try {
68        decryptedTextBytes = cipher.doFinal(encryptedTextBytes);
69    }   catch (IllegalBlockSizeException e) {
70        e.printStackTrace();
71    }   catch (BadPaddingException e) {
72        e.printStackTrace();
73    }
74
75    return new String(decryptedTextBytes);
76
77}
78
79public static String getSalt() throws Exception {
80
81    SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
82    byte[] salt = new byte[20];
83    sr.nextBytes(salt);
84    return new String(salt);
85}