[[servlet-authentication-userdetailsservice]]
= UserDetailsService

You can define custom authentication by exposing a custom `UserDetailsService` as a bean.
For example, the following will customize authentication assuming that `SpringDataUserDetailsService` implements `UserDetailsService`:

NOTE: This is only used if the `AuthenticationManagerBuilder` has not been populated and no `AuthenticationProviderBean` is defined.

[source,java]
----
@Bean
public SpringDataUserDetailsService springDataUserDetailsService() {
	return new SpringDataUserDetailsService();
}
----

You can also customize how passwords are encoded by exposing a `PasswordEncoder` as a bean.
For example, if you use bcrypt you can add a bean definition as shown below:

[source,java]
----
@Bean
public BCryptPasswordEncoder passwordEncoder() {
	return new BCryptPasswordEncoder();
}
----
