In this chapter, we will look at the authentication mechanisms—namely SAML, LDAP, and OAuth/OIDC—supported by Spring Security. This will be a fully hands-on coding chapter. We will build small applications, most of them starting from the base application that we built in Chapter 2, Deep Diving into Spring Security.

The main goal of this chapter is to make you comfortable with implementing the authentication mechanisms most commonly used across your organization, and also to showcase Spring Security module capabilities.

Each of the authentication mechanisms has a project that you can see in the book's GitHub page. However, in the book, we will only cover important aspects of the sample code, to reduce clutter within the chapter.

In this chapter, we will cover the following topics:

• Security Assertion Markup Language
• Lightweight Directory Access Protocol
• OAuth2 and OpenID Connect