网页用md5加密安全么？

MD5加解密比较容易,而且asp里加解密,别人很容易联想到MD5,用户名密码什么的可以自己尝试开发一个简单的加密规则,别人基本是不可能猜到的.

import java.security.*; public class MD5{ public static void main(String[] args) { System.out.println(MD5.getMD5("janson")); } public final static String getMD5(String s){ char hexDigits[] = {'0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f'}; try { byte[] strTemp = s.getBytes(); MessageDigest mdTemp = MessageDigest.getInstance("MD5"); mdTemp.update(strTemp); byte[] md = mdTemp.digest(); int j = md.length; char str[] = new char[j * 2]; int k = 0; for (int i = 0; i < j; i++) { byte byte0 = md[i]; str[k++] = hexDigits[byte0 >>> 4 & 0xf]; str[k++] = hexDigits[byte0 & 0xf]; } return new String(str); } catch (Exception e){ return null; } } }