jHx5L8UP

1import javax.crypto.*;
2import javax.crypto.spec.*;
3import java.security.*;
4import java.security.spec.*;
5import java.util.Base64;
6
7public class AES {
8
9    public static int iterations = 1000;
10    private static String seperator = ";";
11    private static int key_length = 256;
12    private static int salt_length = 64;
13
14    private static final String HASH_ALGORITHM = "PBKDF2WithHmacSHA256";
15    private static final String KEY_ALGORITHM = "AES";
16    private static final String CIPHER_ALGORITHM = "AES/CBC/PKCS5Padding";
17
18    public static void setSaltLength(int length) throws Exception {
19        if((length > 0) && ((length & (length - 1)) == 0))
20            salt_length = length;
21        else
22            throw new Exception("Invalid Salt Length");
23
24    }
25
26    public static void setKeyLength(int length) throws Exception {
27        if(length == 128 || length == 192 || length == 256)
28            key_length = length;
29        else
30            throw new Exception("Invalid Length");
31    }
32
33    public static void setSeperator(String s) throws Exception {
34        if(seperator.matches("[^+=/\w]"))
35            seperator = s;
36        else
37            throw new Exception("Invalid Seperator");
38    }
39
40    public static void setDurationOnCurrentComputer(int milliseconds){
41        char[] password = {'t', 'e', 's', 't'};
42        int i = 1;
43        long duration = 0;
44        while(duration < milliseconds) {
45            i*=2;
46            long t = System.currentTimeMillis();
47            byte[] salt = new byte[64];
48            new SecureRandom().nextBytes(salt);
49            try {
50                createKey(password, salt, i);
51            } catch (Exception e) {
52                e.printStackTrace();
53            }
54            duration = System.currentTimeMillis() - t;
55            System.out.println("i: " + i + " duration: " + duration);
56        }
57        iterations = i;
58    }
59
60    private static SecretKey createKey(char[] password, byte[] salt, int iterations) throws NoSuchAlgorithmException, InvalidKeySpecException {
61        SecretKeyFactory factory = SecretKeyFactory.getInstance(HASH_ALGORITHM);
62        KeySpec spec = new PBEKeySpec(password, salt, iterations, key_length);
63        SecretKey tmp = factory.generateSecret(spec);
64        return new SecretKeySpec(tmp.getEncoded(), KEY_ALGORITHM);
65    }
66
67    public static String encrypt(char[] password, byte[] data) throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidKeyException, InvalidParameterSpecException, BadPaddingException, IllegalBlockSizeException, InvalidKeySpecException {
68        Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
69        byte[] salt = new byte[salt_length];
70        new SecureRandom().nextBytes(salt);
71        cipher.init(Cipher.ENCRYPT_MODE, createKey(password, salt, iterations));
72        AlgorithmParameters params = cipher.getParameters();
73        byte[] iv = params.getParameterSpec(IvParameterSpec.class).getIV();
74        byte[] ciphertext = cipher.doFinal(data);
75        Base64.Encoder e = Base64.getEncoder();
76        return e.encodeToString((e.encodeToString(iv) + seperator + e.encodeToString(ciphertext) + seperator + e.encodeToString(salt)).getBytes());
77    }
78
79    public static String decrypt(char[] password, String ciphertext) throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidAlgorithmParameterException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException, InvalidKeySpecException {
80        Base64.Decoder d = Base64.getDecoder();
81        String[] data = new String(d.decode(ciphertext)).split(seperator);
82        Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
83        cipher.init(Cipher.DECRYPT_MODE, createKey(password, d.decode(data[2]), iterations), new IvParameterSpec(d.decode(data[0])));
84        return new String(cipher.doFinal(d.decode(data[1])));
85    }
86}