tvCy7ft8

1import javax.crypto.spec.*;
2import java.security.*;
3import javax.crypto.*;
4  
5public class RC4
6{
7   private static String algorithm = "RC4";
8  
9   public static void main(String []args) throws Exception {
10      String toEncrypt = "hello world";
11  
12      System.out.println("Encrypting...");
13      byte[] encrypted = encrypt(toEncrypt, "password");
14  
15      System.out.println("Decrypting...");
16      String decrypted = decrypt(encrypted, "password");
17     
18      System.out.println("Decrypted text: " + decrypted);
19   }
20  
21   public static byte[] encrypt(String toEncrypt, String key) throws Exception {
22      // create a binary key from the argument key (seed)
23      SecureRandom sr = new SecureRandom(key.getBytes());
24      KeyGenerator kg = KeyGenerator.getInstance(algorithm);
25      kg.init(sr);
26      SecretKey sk = kg.generateKey();
27  
28      // create an instance of cipher
29      Cipher cipher = Cipher.getInstance(algorithm);
30  
31      // initialize the cipher with the key
32      cipher.init(Cipher.ENCRYPT_MODE, sk);
33  
34      // enctypt!
35      byte[] encrypted = cipher.doFinal(toEncrypt.getBytes());
36  
37      return encrypted;
38   }
39  
40   public static String decrypt(byte[] toDecrypt, String key) throws Exception {
41      // create a binary key from the argument key (seed)
42      SecureRandom sr = new SecureRandom(key.getBytes());
43      KeyGenerator kg = KeyGenerator.getInstance(algorithm);
44      kg.init(sr);
45      SecretKey sk = kg.generateKey();
46  
47      // do the decryption with that key
48      Cipher cipher = Cipher.getInstance(algorithm);
49      cipher.init(Cipher.DECRYPT_MODE, sk);
50      byte[] decrypted = cipher.doFinal(toDecrypt);
51  
52      return new String(decrypted);
53   }
54}