Hash string using MD5

This is an example function to create MD5 hash

Usage:

SecurityUtil.md5("somestring")

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * Utility class for security hashing
 *
 * @author Ali Irawan
 * @version 1.0
 */
public class SecurityUtil {

    public static String md5(String text) throws NoSuchAlgorithmException,
            UnsupportedEncodingException {
        MessageDigest md;

        md = MessageDigest.getInstance("MD5");
        byte[] md5Hash = new byte[32];

        md.update(text.getBytes("iso-8859-1"), 0, text.length());
        md5Hash = md.digest();
        return convertToHex(md5Hash);
    }

    private static String convertToHex(byte[] data) {
        StringBuffer buf = new StringBuffer();
        for (int i = 0; i < data.length; i++) {
            int halfbyte = (data[i] >>> 4) & 0x0F;
            int two_halfs = 0;
            do {
                if ((0 <= halfbyte) && (halfbyte <= 9))
                    buf.append((char) ('0' + halfbyte));
                else
                    buf.append((char) ('a' + (halfbyte - 10)));
                halfbyte = data[i] & 0x0F;
            } while (two_halfs++ < 1);
        }
        return buf.toString();
    }
}