checkpasssalt.java

Java安全性编程实例,解压看说明

import java.io.*;
import java.security.*;
public class CheckPassSalt{
    public static void main(String args[ ]) throws Exception{
        /* 读取保存的盐和口令摘要 */
        String name="";
        String  passwd="";
        String  salts="";
        BufferedReader in = new BufferedReader(new FileReader("passwdsalt.txt"));
        while ((name = in.readLine( )) != null) {
            salts=in.readLine( );
            passwd=in.readLine( );
            if (name.equals(args[0])){
                break;
            }
        }
        String salttmp[ ]=salts.split(",");
        byte salt[ ]=new byte[salttmp.length];

        for (int i=0; i<salt.length; i++){
            salt[i]=Byte.parseByte(salttmp[i]);
        }
        /* 生成用户输入的口令摘要 */
        MessageDigest m=MessageDigest.getInstance("MD5");
        m.update(salt);
        m.update(args[1].getBytes("UTF8"));
        byte s[ ]=m.digest( );
        String result="";
        for (int i=0; i<s.length; i++){
            result+=Integer.toHexString((0x000000ff & s[i]) | 0xffffff00).substring(6);
        }
        /* 检验口令摘要是否匹配 */
        if(name.equals(args[0])&&result.equals(passwd)){
            System.out.println("OK");
        }
        else{
            System.out.println("Wrong password");
        }
    }
}