title: Single Sign On + Microservices
body: <p>I have a couple web apps which I will try to convert in microservices (In the future maybe I will have more). Before this, I would like to create a microservice for authentication and authorization which permits SSO.</p>
  
  <p>I read a lot about <a href="http://jasig.github.io/cas/4.1.x/index.html" rel="nofollow">CAS</a> but I have the feeling that seems an old solution and I don't know if it is a good idea for microservices' architecture.</p>
  
  <p>On the other hand I have been researching about Oauth2, I know it is only for authorizations (but you need to be authenticated for that) so.. maybe it could be a good option. Also I have found a good guide for implement <a href="https://spring.io/guides/tutorials/spring-security-and-angular-js/#_sso_with_oauth2_angular_js_and_spring_security_part_v" rel="nofollow">Oauth2 SSO with Spring</a>. However Oauth2 is for third-party so.. neither know if it is the best solution.</p>
  
  <p>As you see, I'm a bit confused . Other terms and tecnologies are in my head like SAML, OpenId... But I don't know which choose.</p>