java.security.*包下MessageDigest类的简单应用 MD5加密
先通过MD5加密之后，再来一次可逆的加密。 *顺序可以调整，可以选择先用可逆加密，然后再用MD5加密 */ public class MD5andKL{ //MD5加密。32位 public static String MD5(String inStr) { MessageDigest md5 = null; try { md5 = MessageDigest.getInstance("MD5"); } catch (Exception e) { System.out.println(e.toString()); e.printStackTrace(); return ""; } char[] charArray = inStr.toCharArray(); byte[] byteArray = new byte[charArray.length]; for (int i = 0; i < charArray.length; i++) byteArray[i] = (byte) charArray[i]; byte[] md5Bytes = md5.digest(byteArray); StringBuffer hexValue = new StringBuffer();for (int i = 0; i < md5Bytes.length; i++) { int val = ((int) md5Bytes[i]) & 0xff; if (val < 16) hexValue.append("0"); hexValue.append(Integer.toHexString(val)); }return hexValue.toString(); }//可逆的加密算法 public static String KL(String inStr){ //String s = new String(inStr); char[] a = inStr.toCharArray(); for (int i = 0;i <a.length;i++) { a[i] = (char)(a[i]^'t'); } String s=new String(a); return s; } //加密后解密 public static String JM(String inStr){ char[] a=inStr.toCharArray(); for (int i = 0;i <a.length;i++) { a[i]= (char)(a[i]^'t'); } String k=new String(a); return k; } //测试主函数 public static void main (String args[]){ String s = new String("admin"); System.out.println("原始："+s); System.out.println("MD5后："+MD5(s)); System.out.println("MD5后再加密："+KL(MD5(s))); System.out.println("解密为MD5后的："+JM(KL(MD5(s)))); }