import java.security.MessageDigest;
public class MD5Util {
/***
* MD5加密 生成32位md5码
* @param 待加密字符串
* @return 返回32位md5码
*/
public static String MD5(String inStr) throws Exception {
MessageDigest md5 = null;
try {
md5 = MessageDigest.getInstance("MD5");
} catch (Exception e) {
System.out.println(e.toString());
e.printStackTrace();
return "";
}
byte[] byteArray = inStr.getBytes("UTF-8");
byte[] md5Bytes = md5.digest(byteArray);
StringBuffer hexValue = new StringBuffer();
for (int i = ; i < md5Bytes.length; i++) {
int val = ((int) md5Bytes[i]) & 0xff;
if (val < ) {
hexValue.append("");
}
hexValue.append(Integer.toHexString(val));
}
return hexValue.toString();
}
// 一次加密两次解密
public static String convertMD5(String inStr) {
char[] a = inStr.toCharArray();
for (int i = ; i < a.length; i++) {
a[i] = (char) (a[i] ^ 't');
}
String s = new String(a);
return s;
}
// 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 = ; 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 = ; i < a.length; i++) {
a[i] = (char) (a[i] ^ 't');
}
String k = new String(a);
return k;
}
/**
* 测试主函数
*
* @param args
* @throws Exception
*/
//密码先加密，然后再比较是否相等
public static void main(String args[]) throws Exception {
String str = new String("abc");
System.out.println("原始：" + str);
System.out.println("MD5后：" + MD5(str));
System.out.println(convertMD5(str));
System.out.println(convertMD5(convertMD5(str)));
String s = new String("");
// 4297f44b13955235245b2497399d7a93
System.out.println("原始：" + str);
System.out.println("MD5后：" + MD5(str));
System.out.println("MD5后再加密：" + KL(MD5(str)));
System.out.println("解密为MD5后的：" + JM(KL(MD5(str))));
}
}
