MD5加密技术,通俗易懂

清疚 2021-10-24 00:24 206阅读 0赞

package com.shuaishuai;
    
    import java.security.MessageDigest;
    
    public class Md5 {
    
        /***
         *  MD5加码 生成32位md5码
         */
        public static String string2MD5(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();
    
        }
    
        /**
         * 加密解密算法 执行一次加密，两次解密
         */
        public static String convertMD5(String inStr){
            char[] a = inStr.toCharArray();
            for (int i = 0; i < a.length; i++){
                a[i] = (char) (a[i] ^ 'g');  //异或运算
            }
            String s = new String(a);
            return s;
    
        }
    
        // 测试主函数
        public static void main(String args[]) {
            String s = "123luyaoLUYAO";
            System.out.println("原始密码：" + s);
            System.out.println("MD5后：" + string2MD5(s));
            System.out.println("加密密码：" + convertMD5(s));
            System.out.println("长 度:"+convertMD5(s).length()+"数据库存储");
            System.out.println("解密密码：" + convertMD5(convertMD5(s)));
    
        }
    }