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1package javaapplication21;
2import java.security.Key;
3import java.security.KeyPair;
4import java.security.KeyPairGenerator;
5import java.security.Security;
6import java.security.SecureRandom;
7import javax.crypto.Cipher;
8import java.security.InvalidKeyException;
9import java.security.NoSuchAlgorithmException;
10import java.security.spec.InvalidKeySpecException;
11import javax.crypto.BadPaddingException;
12import javax.crypto.IllegalBlockSizeException;
13import javax.crypto.NoSuchPaddingException;
14import javax.crypto.SecretKey;
15import javax.crypto.SecretKeyFactory;
16import javax.crypto.ShortBufferException;
17import javax.crypto.spec.PBEKeySpec;
18import javax.crypto.spec.SecretKeySpec;
19import javax.rmi.CORBA.Util;
20
21
22/**
23 *
24 * @author student
25 */
26public class JavaApplication21 {
27    
28    public static byte[] hexStringToByteArray(String s) {
29    int len = s.length();
30    byte[] data = new byte[len / 2];
31    for (int i = 0; i < len; i += 2) {
32        data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
33                             + Character.digit(s.charAt(i+1), 16));
34    }
35    return data;
36}
37
38
39    public static void main(String[] args) throws ShortBufferException, IllegalBlockSizeException, InvalidKeyException, NoSuchAlgorithmException, NoSuchPaddingException, BadPaddingException, InvalidKeySpecException {
40        byte[] keyBytes = new byte[16];
41        // declare secure PRNG
42        SecureRandom myPRNG = new SecureRandom();
43        myPRNG.nextBytes(keyBytes);
44        SecretKeySpec myKey = new SecretKeySpec(keyBytes, "AES");
45        // instantiate AES object for ECB with no padding
46        Cipher myAES = Cipher.getInstance("AES/ECB/NoPadding");
47        // initialize AES objecy to encrypt mode
48        myAES.init(Cipher.ENCRYPT_MODE, myKey);
49        // initialize plaintext
50        byte[] plaintext = new byte[16]; // ii dai tu un text
51        plaintext = hexStringToByteArray("e04fd020ea3a6910a2d808002b30309d");
52        //initialize ciphertext
53        byte[] ciphertext = new byte[16];
54        // update cipher with the plaintext
55        int cLength = myAES.update(plaintext, 0, plaintext.length, ciphertext,
56            0);
57        // process remaining blocks of plaintext
58        cLength += myAES.doFinal(ciphertext, cLength);
59        // print plaintext and ciphertext
60        System.out.println("plaintext: " +
61            javax.xml.bind.DatatypeConverter.printHexBinary(plaintext));
62        System.out.println("ciphertext: " +
63            javax.xml.bind.DatatypeConverter.printHexBinary(ciphertext));
64        // initialize AES for decryption
65        myAES.init(Cipher.DECRYPT_MODE, myKey);
66        // initialize a new array of bytes to place the decryption
67        byte[] dec_plaintext = new byte[16];
68        cLength = myAES.update(ciphertext, 0, ciphertext.length, dec_plaintext,
69            0);
70        // process remaining blocks of ciphertext
71        cLength += myAES.doFinal(dec_plaintext, cLength);
72        // print the new plaintext (hopefully identical to the initial one)
73        System.out.println("decrypted: " +
74            javax.xml.bind.DatatypeConverter.printHexBinary(dec_plaintext));
75        // TODO code application logic here
76        char[] password = "short_password".toCharArray();
77        byte[] salt = new byte[16];
78        int iteration_count = 10000;
79        int key_size = 128;
80        // set salt values to random
81        myPRNG.nextBytes(salt);
82
83        // initialize key factory for HMAC-SHA1 derivation
84        SecretKeyFactory keyFactory =
85            SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
86        // set key specification
87        PBEKeySpec pbekSpec = new PBEKeySpec(password, salt, iteration_count,
88            key_size);
89        // generate the key
90        SecretKey myAESPBKey = new SecretKeySpec(
91            keyFactory.generateSecret(pbekSpec).getEncoded(), "AES");
92        // print the key
93        System.out.println("AES key: " +
94            javax.xml.bind.DatatypeConverter.printHexBinary(myAESPBKey.getEncoded()));
95    }
96
97}