使用BCrypt算法加密存储登录密码

在前一节使用数据库进行用户认证(form login using database)里，我们学习了如何把“登录帐号、密码”存储在db中，但是密码都是明文存储的，显然不太讲究。这一节将学习如何使用spring security3新加入的bcrypt算法，将登录加密存储到db中，并正常通过验证。

一、Bcrypt算法

 1 int t = 0;
 2 String password = "123456";
 3 System.out.println(password + " -> ");
 4 for (t = 1; t <= 10; t++) {
 5     BCryptPasswordEncoder passwordEncoder = new BCryptPasswordEncoder();
 6     String hashedPassword = passwordEncoder.encode(password);
 7     System.out.println(hashedPassword);
 8 }
 9 
10 password = "MIKE123";
11 System.out.println(password + " -> ");
12 for (t = 1; t <= 10; t++) {
13     BCryptPasswordEncoder passwordEncoder = new BCryptPasswordEncoder();
14     String hashedPassword = passwordEncoder.encode(password);
15     System.out.println(hashedPassword);
16 }

输出如下：

 123456 -> 
 2a2a10$.Cjkvbgr2JzGkag9IdbT.Oc/sbY7wVqLgAHws7HCxqcI7eczKtCLq
 2a2a10$OCOuRV0Wy7ncCND4LcKfMunVEWOzMOyyU95u5TkTRmJqYbsJNecEK
 2a2a10$TXttsDZUaeEb2zX6wiwN0eqREKFoCDyh81Kfa6BgAcZ2hyqPNC0Ra
 2a2a10$FfLx/gxq.FyeOBb0nbaVeusLhQjASSdY7w45i1ACl/rcYQMmhaXV2
 2a2a10$JdPXAxmuz.WTP5gxYiYseeKRSM/HTFzJJdACcDQ4MdhaaLmC0SjI.
 2a2a10$yVEWf2MrwjCyi51rUKqQle/MZb7vwcOf6Gwp.hDT2ZUchlyAtJ4pO
 2a2a10$FfJg2ATit7btKfJovL6zmug//8rzToQn7FO.fxOzo1KtNNfhWKuca
 2a2a10$pOLMkd13n7i3DtVijLEqze1zeURpjtVz5rAx1qOAPqCQvjGG/d6D.
 2a2a10$fQ32i8JsjjmqVRpiEsgT3ekTKtrfXn.JNl69beWEx0.YgdX.SEx5e
 2a2a10$78brJFSdftip0XXYx4rS6ewdu4SiSsMIBY9oNcLhAZwg3GysRGk2m
 MIKE123 -> 
 2a2a10$U6KVh1NGxAIGYiM4YVgn6OAQt6ayAoLkh2lODv16rSpkS1iqfbR2C
 2a2a10$t0FlEOBLEB8VwWJVoZRrweIRV0XyoBgm29c0SMqfqRK3ZBuvhgYbS
 2a2a10$QpW6nHnWNhbTTjLq/NbzBu2Unp8ijwyPeUx2N2eMFWReFezosZ5fi
 2a2a10$LtPzoQU0IluAgvP3/WhWquUv2AcDRh2ENhAeWDquiN/spitZYe/7q
 2a2a10$Qcx7vUudzF7qzTjz.QpLKOby0tXQ4j.uqkInS1n4/6oD2r2eL0rZW
 2a2a10$yZw7cdq1y9sjX8nZhYynseWjQ4jeVv76fPmBl.sg2xPvb8cyXD8Sq
 2a2a10$kTmT6BQQE5LyRZ00Qas77.F5kxK0GxsW402ExosQswxmG.eBdgIZW
 2a2a10$SRfHDNM.m3qX5y1O7V/cp.hQqgaXnKzfxBGRhLkAF39bufejuOieu
 2a2a10$Sw5w2kTImJ5Y8UNlE/5/9OLaUgYxhCXU3P3gFBdEbs9PL8pCl60Q2
 2a2a10$0mN8kNAl9GNr0c4K1Nr0b.MIcBW0QcPHB/f20hgeBuRfwvgZXT6hG
从以上输出结果发现bcrypt算法与md5/sha算法有一个很大的区别，每次生成的hash值都是不同的，这样暴力猜解起来或许要更困难一些。同时大家可能也发现了，加密后的字符长度比较长，有60位，所以用户表中密码字段的长度，如果打算采用bcrypt加密存储，字段长度不得低于60.

二、spring-security.xml

 1 <beans:beans xmlns="http://www.springframework.org/schema/security"
 2     xmlns:beans="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 3     xsi:schemaLocation="http://www.springframework.org/schema/beans
 4     http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
 5     http://www.springframework.org/schema/security
 6     http://www.springframework.org/schema/security/spring-security-3.2.xsd">
 7 
 8     <http auto-config="true" use-expressions="true">
 9         <intercept-url pattern="/admin**" access="hasRole('ADMIN')" />
10         
11         <access-denied-handler error-page="/403" />
12         <form-login login-page="/login" default-target-url="/welcome"
13             authentication-failure-url="/login?error" username-parameter="username"
14             password-parameter="password" />
15         <logout logout-success-url="/login?logout" />
16         
17         <csrf />
18     http>
19 
20     
21     <authentication-manager>
22         <authentication-provider>
23             <password-encoder ref="encoder" />
24             <jdbc-user-service data-source-ref="dataSource"
25                 users-by-username-query="select d_username username,d_password password, d_enabled enabled from t_users where d_username=?"
26                 authorities-by-username-query="select d_username username, d_role role from t_user_roles where d_username=?  " />
27         authentication-provider>
28     authentication-manager>
29 
30     <beans:bean id="encoder"
31         class="org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder">
32         <beans:constructor-arg name="strength" value="9" />
33     beans:bean>
34 
35 beans:beans>

对比上一节的内容，只是增加23行、30-33行

最后要做的事情，就是把db中原来明文的密码值，改成经过bcrypt加密后的字符串即可。

tips:如果你仍然喜欢用传统的sha算法来处理密码，只要把23行改成 sha" />  就可以了

参考文章：Spring Security password hashing example