Source code: mindbright/security/Cipher.java
1 /******************************************************************************
2 *
3 * Copyright (c) 1998,99 by Mindbright Technology AB, Stockholm, Sweden.
4 * www.mindbright.se, info@mindbright.se
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 *****************************************************************************
17 * $Author: nallen $
18 * $Date: 2001/11/12 16:31:14 $
19 * $Name: $
20 *****************************************************************************/
21 package mindbright.security;
22
23 public abstract class Cipher {
24
25 public static Cipher getInstance(String algorithm) {
26 Class c;
27 try {
28 c = Class.forName("mindbright.security." + algorithm);
29 return (Cipher)c.newInstance();
30 } catch(Throwable t) {
31 return null;
32 }
33 }
34
35 public byte[] encrypt(byte[] src) { byte[] dest = new byte[src.length];
36 encrypt(src, 0, dest, 0, src.length);
37 return dest; }
38 public abstract void encrypt(byte[] src, int srcOff, byte[] dest, int destOff, int len);
39 public byte[] decrypt(byte[] src) { byte[] dest = new byte[src.length];
40 decrypt(src, 0, dest, 0, src.length);
41 return dest; }
42 public abstract void decrypt(byte[] src, int srcOff, byte[] dest, int destOff, int len);
43 public abstract void setKey(byte[] key);
44
45 public void setKey(String key) {
46 MessageDigest md5;
47 byte[] mdKey = new byte[32];
48 try {
49 md5 = MessageDigest.getInstance("MD5");
50 md5.update(key.getBytes());
51 byte[] digest = md5.digest();
52 System.arraycopy(digest, 0, mdKey, 0, 16);
53 System.arraycopy(digest, 0, mdKey, 16, 16);
54 } catch(Exception e) {
55 // !!!
56 System.out.println("MD5 not implemented, can't generate key out of string!");
57 System.exit(1);
58 }
59 setKey(mdKey);
60 }
61
62 }