cTNdQ3jY

1package symmetric;
2
3import javax.crypto.Cipher;
4import javax.crypto.NoSuchPaddingException;
5import javax.crypto.SecretKey;
6import javax.crypto.spec.IvParameterSpec;
7import javax.crypto.spec.SecretKeySpec;
8import java.security.InvalidKeyException;
9import java.security.NoSuchAlgorithmException;
10import java.security.SecureRandom;
11import java.util.Base64;
12
13public class DES {
14
15    private SecretKey secretKey;
16    private String cryptoMode;
17    private IvParameterSpec initVector;
18    private Cipher cipher;
19
20
21    public DES(String key, String cryptoMode) throws Exception {
22        this.cryptoMode = cryptoMode;
23        byte[] base64Key = Base64.getDecoder().decode(key);
24        this.secretKey = new SecretKeySpec(base64Key,0,base64Key.length,"DESede");
25        this.cipher = Cipher.getInstance("DESede/"+ cryptoMode +"/PKCS5Padding");
26
27        SecureRandom randomSecureRandom = SecureRandom.getInstance("SHA1PRNG");
28        byte[] iv = new byte[cipher.getBlockSize()];
29        randomSecureRandom.nextBytes(iv);
30        this.initVector = new IvParameterSpec(iv);
31
32    }
33
34
35    public String encrypt(String text) throws Exception {
36
37        if (cryptoMode.equals("ECB")) {
38            cipher.init(Cipher.ENCRYPT_MODE, secretKey);
39        } else {
40            cipher.init(Cipher.ENCRYPT_MODE, secretKey, initVector);
41        }
42
43        byte[] encrypted = cipher.doFinal(text.getBytes());
44        return Base64.getEncoder().encodeToString(encrypted);
45    }
46
47    public String decrypt(String cipherText) throws Exception {
48
49        if (cryptoMode.equals("ECB")) {
50            cipher.init(Cipher.DECRYPT_MODE, secretKey);
51        } else {
52            cipher.init(Cipher.DECRYPT_MODE, secretKey, initVector);
53        }
54
55        byte[] decrypted = cipher.doFinal(Base64.getDecoder().decode(cipherText));
56        return new String(decrypted);
57    }
58
59
60    public static void main(String[] args) throws Exception{
61        DES des = new DES("133457799AAA","ECB");
62
63        String encrpyted = des.encrypt("kurac");
64
65        String dectrpyted = des.decrypt(encrpyted);
66
67        System.out.println(dectrpyted);
68
69    }
70
71
72}