1 import java.io.UnsupportedEncodingException;
2 import java.security.MessageDigest;
3 import java.security.NoSuchAlgorithmException;
4 import java.util.Arrays;
5 public class SignatureUtil {
6 private static String encodingCharset = "UTF-8";
7 public static String hmacSign(String aValue, String aKey) {
8 byte k_ipad[] = new byte[64];
9 byte k_opad[] = new byte[64];
10 byte keyb[];
11 byte value[];
12 try {
13 keyb = aKey.getBytes(encodingCharset);
14 value = aValue.getBytes(encodingCharset);
15 } catch (UnsupportedEncodingException e) {
16 keyb = aKey.getBytes();
17 value = aValue.getBytes();
18 }
19 Arrays.fill(k_ipad, keyb.length, 64, (byte) 54);
20 Arrays.fill(k_opad, keyb.length, 64, (byte) 92);
21 for (int i = 0; i < keyb.length; i++) {
22 k_ipad[i] = (byte) (keyb[i] ^ 0x36);
23 k_opad[i] = (byte) (keyb[i] ^ 0x5c);
24 }
25 MessageDigest md = null;
26 try {
27 md = MessageDigest.getInstance("MD5");
28 } catch (NoSuchAlgorithmException e) {
29 return null;
30 }
31 md.update(k_ipad);
32 md.update(value);
33 byte dg[] = md.digest();
34 md.reset();
35 md.update(k_opad);
36 md.update(dg, 0, 16);
37 dg = md.digest();
38 return toHex(dg);
39 }
40 public static String toHex(byte input[]) {
41 if (input == null)
42 return null;
43 StringBuffer output = new StringBuffer(input.length * 2);
44 for (int i = 0; i < input.length; i++) {
45 int current = input[i] & 0xff;
46 if (current < 16)
47 output.append("0");
48 output.append(Integer.toString(current, 16));
49 }
50 return output.toString();
51 }
52 }
