MD5加盐算法

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原文链接
http://blog.csdn.net/zhanglianhai555/article/details/47081001?utm_source=tuicool&utm_medium=referral

完整代码如下

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package com.cloudcof.cofserver.util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Random;


public class MD5WithSalt {
	
	public static String generate(String password){
		Random r = new Random();
		StringBuilder sb = new StringBuilder(16);
		
		//拼接两个在区间[0,99999999)内的整数，不足16位补0
		sb.append(r.nextInt(99999999)).append(r.nextInt(99999999));
		int len = sb.length();
		if(len<16){
			for (int i = 0; i < 16-len; i++) {
				sb.append("0");
			}
		}
		
		String salt = sb.toString();
		password = md5Hex(password+salt);
		
		char[] cs = new char[48];
		//形如_o_ _o_ _o_(_代表MD5消息摘要，o代表salt)
		//MD5是32位，salt是16位
		for(int i=0;i<48;i+=3){
			cs[i] = password.charAt(i/3*2);
			cs[i+1] = salt.charAt(i/3);
			cs[i+2] = password.charAt(i/3*2+1);
		}
		
		return new String(cs);
	}
	
	public static boolean verify(String password,String md5WithSalt){
		char[] md5Chars = new char[32];
		char[] saltChars = new char[16];
		for(int i=0;i<48;i+=3){
			//每经过一次循环，md5Chars获得两个值并设置。
			md5Chars[i/3*2] = md5WithSalt.charAt(i);
			saltChars[i/3] = md5WithSalt.charAt(i+1);
			md5Chars[i/3*2+1] = md5WithSalt.charAt(i+2);
		}
		String salt = new String(saltChars);
		return md5Hex(password+salt).equals(new String(md5Chars));
	}
	
	public static String md5Hex(String src){
		MessageDigest md5 = null;
		try {
			md5 = MessageDigest.getInstance("MD5");
		} catch (NoSuchAlgorithmException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		byte[] bs = md5.digest(src.getBytes());
		return new String(new Hex().encode(bs));
	}
	
//	public static void main(String[] args) {
//		String password = generate("admin");
//		System.out.println(password);
//		System.out.println(verify("admin", password));
//	}
}

//类的职能：二进制转换成十六进制
class Hex{
	String encode(byte[] b){
		String hs = "";
		String stmp = "";
		for (int i = 0; i < b.length; i++) {
			stmp = (java.lang.Integer.toHexString(b[i]&0XFF));
			if (stmp.length() == 1) {
				hs = hs+"0"+stmp;
			}else{
				hs = hs+stmp;
			}
		}
		
		return hs.toUpperCase();
	}
}

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