s0bGj88m

1     import java.security.SecureRandom;
2     import javax.crypto.Cipher;
3     import javax.crypto.KeyGenerator;
4     import javax.crypto.SecretKey;
5     import javax.crypto.spec.SecretKeySpec;
6
7     public class SimpleCrypto {
8
9public  String encrypt(String seed, String cleartext) throws Exception {
10        byte[] rawKey = getRawKey(seed.getBytes());
11        byte[] result = encrypt(rawKey, cleartext.getBytes());
12        return toHex(result);
13}
14
15public  String decrypt(String seed, String encrypted) throws Exception {
16        byte[] rawKey = getRawKey(seed.getBytes());
17        byte[] enc = toByte(encrypted);
18        byte[] result = decrypt(rawKey, enc);
19        return new String(result);
20}
21
22//done
23private  byte[] getRawKey(byte[] seed) throws Exception {
24        KeyGenerator kgen = KeyGenerator.getInstance("AES");
25        SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
26        sr.setSeed(seed);
27    kgen.init(128, sr); // 192 and 256 bits may not be available
28    SecretKey skey = kgen.generateKey();
29    byte[] raw = skey.getEncoded();
30    return raw;
31}
32
33
34private  byte[] encrypt(byte[] raw, byte[] clear) throws Exception {
35    SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
36        Cipher cipher = Cipher.getInstance("AES");
37    cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
38    byte[] encrypted = cipher.doFinal(clear);
39        return encrypted;
40}
41
42private  byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
43    SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
44        Cipher cipher = Cipher.getInstance("AES");
45    cipher.init(Cipher.DECRYPT_MODE, skeySpec);
46    byte[] decrypted = cipher.doFinal(encrypted);
47        return decrypted;
48}
49
50public  String toHex(String txt) {
51        return toHex(txt.getBytes());
52}
53public  String fromHex(String hex) {
54        return new String(toByte(hex));
55}
56
57public  byte[] toByte(String hexString) {
58        int len = hexString.length()/2;
59        byte[] result = new byte[len];
60        for (int i = 0; i < len; i++)
61                result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();
62        return result;
63}
64
65public  String toHex(byte[] buf) {
66        if (buf == null)
67                return "";
68        StringBuffer result = new StringBuffer(2*buf.length);
69        for (int i = 0; i < buf.length; i++) {
70                appendHex(result, buf[i]);
71        }
72        return result.toString();
73}
74private final static String HEX = "0123456789ABCDEF";
75private  void appendHex(StringBuffer sb, byte b) {
76        sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));
77}
78
79  }
80