How To Create A Two-Factor Authentication (2FA) In Spring Boot

Two-factor authentication (2FA) module in Spring Boot using the Spring Security framework:

Step 1: Set Up a Spring Boot Project Set up a Spring Boot project if you haven’t already done so. You can use Spring Initializr or create a project from scratch.

Step 2: Add Dependencies In your Spring Boot project, add the necessary dependencies to your pom.xml file:

				
					<!-- Spring Security -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-security</artifactId>
</dependency>

<!-- Spring Web -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<!-- Google Authenticator -->
<dependency>
    <groupId>com.warrenstrange</groupId>
    <artifactId>googleauth</artifactId>
    <version>1.4.0</version>
</dependency>
				
			

Step 3: Configure Spring Security In your Spring Boot project, create a configuration class to configure Spring Security and enable two-factor authentication:

				
					@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Autowired
    private UserDetailsServiceImpl userDetailsService;

    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.userDetailsService(userDetailsService);
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .authorizeRequests()
                .antMatchers("/login", "/register").permitAll()
                .anyRequest().authenticated()
                .and()
            .formLogin()
                .loginPage("/login")
                .defaultSuccessUrl("/dashboard")
                .permitAll()
                .and()
            .logout()
                .logoutSuccessUrl("/login")
                .permitAll()
                .and()
            .csrf().disable();
    }
}
				
			

In this example, we configure Spring Security to permit access to the login and registration pages without authentication. All other requests require authentication. The form login is configured to redirect to the /dashboard page after successful login.

Step 4: Implement UserDetailsService Create a custom implementation of the UserDetailsService interface to load user details from your data source:

				
					@Service
public class UserDetailsServiceImpl implements UserDetailsService {

    // Implement the loadUserByUsername method to load user details

}
				
			

In the loadUserByUsername method, load the user details, including the secret key for two-factor authentication, from your data source. You can use any data source of your choice, such as a database.

Step 5: Implement Two-Factor Authentication Create a service class to handle the generation and verification of two-factor authentication codes:

				
					@Service
public class TwoFactorAuthenticationService {

    public String generateSecretKey() {
        return new GoogleAuthenticator().createCredentials().getKey();
    }

    public boolean verifyCode(String secretKey, int code) {
        return new GoogleAuthenticator().authorize(secretKey, code);
    }
}
				
			

In this example, we use the GoogleAuthenticator class from the googleauth library to generate and verify two-factor authentication codes.

Step 6: Implement Login and Registration Controllers Create controllers for login and registration functionality:

				
					@Controller
public class LoginController {

    @Autowired
    private TwoFactorAuthenticationService twoFactorAuthenticationService;

    @GetMapping("/login")
    public String login() {
        return "login";
    }

    @PostMapping("/login")
    public String processLogin(@RequestParam("username") String username,
                               @RequestParam("password") String password,
                               @RequestParam("code") int code,
                               HttpSession session) {
        // Perform authentication and two-factor code verification

        return "redirect:/dashboard";
    }
}

@Controller
public class RegistrationController {

    @Autowired
    private TwoFactorAuthenticationService twoFactorAuthenticationService;

    @Autowired
    private UserDetailsService userDetailsService;

    @GetMapping("/register")
    public String register() {
        return "register";
    }

    @PostMapping("/register")
    public String processRegistration(@RequestParam("username") String username,
                                      @RequestParam("password") String password,
                                      RedirectAttributes redirectAttributes) {
        // Perform user registration and save the secret key for two-factor authentication

        return "redirect:/login";
    }
}
				
			

In these controllers, handle the login and registration logic, including authentication, two-factor code verification, user registration, and storing the secret key for two-factor authentication.

Step 7: Implement the Login and Registration Views Create the login and registration views using your preferred view templating engine, such as Thymeleaf or JSP. You need to include input fields for username, password, and two-factor authentication code.

Step 8: Test the Two-Factor Authentication You can now test the two-factor authentication functionality by logging in as a user, entering the two-factor authentication code, and verifying its correctness.

Please note that this is a basic example of a two-factor authentication module in Spring Boot using Spring Security and the googleauth library. You can further customize and enhance the module based on your specific requirements, such as integrating with a database, implementing user registration and login flows, or using a different two-factor authentication library.