Registration with Spring Security – Password Encoding

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1. Overview

This article discusses a critical part of the registration process – password encoding – basically not storing the password in plaintext.

There are a few encoding mechanism supported by Spring Security – and for the article we’ll use BCrypt, as it’s usually the best solution available.

Most of the other mechanism, such as the MD5PasswordEncoder and ShaPasswordEncoder use weaker algorithms and are now deprecated.

2. Define the Password Encoder

We’ll start by defining the simple BCryptPasswordEncoder as a bean in our configuration:

@Bean
public PasswordEncoder passwordEncoder() {
    return new BCryptPasswordEncoder();
}

Older implementations – such as SHAPasswordEncoder – would require the client to pass in a salt value when encoding the password.

BCrypt however will internally generate a random salt instead. This is important to understand, because it means that each call will have a different result, and so we need to only encode the password once.

Also be aware that the BCrypt algorithm generates a String of length 60, so we need to make sure that the password will be stored in a column that can accommodate it. A common mistake is to create a column of a different length and then get an Invalid Username or Password error at authentication time.

3. Encode the Password on Registration

We will now use the PasswordEncoder in our UserService to hash the password during the user registration process:

Example 3.1. – The UserService Hashes the Password

@Autowired
private PasswordEncoder passwordEncoder;

@Override
public User registerNewUserAccount(UserDto accountDto) throws EmailExistsException {
    if (emailExist(accountDto.getEmail())) {
        throw new EmailExistsException(
          "There is an account with that email adress:" + accountDto.getEmail());
    }
    User user = new User();
    user.setFirstName(accountDto.getFirstName());
    user.setLastName(accountDto.getLastName());
    
    user.setPassword(passwordEncoder.encode(accountDto.getPassword()));
    
    user.setEmail(accountDto.getEmail());
    user.setRole(new Role(Integer.valueOf(1), user));
    return repository.save(user);
}

4. Encode the Password on Authentication

Let’s now handle the other half of this process and encode the password when the user authenticates.

First, we need to inject the password encoder bean we defined earlier into our authentication provider:

@Autowired
private UserDetailsService userDetailsService;

@Bean
public DaoAuthenticationProvider authProvider() {
    DaoAuthenticationProvider authProvider = new DaoAuthenticationProvider();
    authProvider.setUserDetailsService(userDetailsService);
    authProvider.setPasswordEncoder(encoder());
    return authProvider;
}

The security configuration is simple:

• we are injecting our implementation of the users details service
• we are defining an authentication provider that references our details service
• we are also enabling the password encoder

And finally, we need to reference this auth provider in our security XML configuration:

<authentication-manager>
    <authentication-provider ref="authProvider" />
</authentication-manager>

5. Conclusion

This quick tutorial continues the Registration series by showing how to properly store the password in the database by leveraging the simple but very powerful BCrypt implementation.

The full implementation of this Registration with Spring Security tutorial can be found in the github project – this is an Eclipse based project, so it should be easy to import and run as it is.

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