Single sign on in iOS apps

there are 4 answers:

  1. Work with OAuth 2.0

  2. Use OpenID

  3. Apply token-based authentication with OpenID Connect and NAPPS

  4. Extend beyond SSO

  5. Use OpenID:-

OpenID is a way to resolve the single-site restriction imposed by OAuth 2.0. As with OAuth, OpenID is supported by all leading authentication providers, such as Microsoft, Google, Facebook, and Twitter. OpenID allows one set of user credentials to access multiple sites. For instance, a Google ID and password can be used to access all of Google’s services. Similarly, a company can use OpenID with OAuth 2.0 to connect a user account from the web, desktop, or mobile to all services using the same authentication. This can include custom solutions, APIs, Office 365, and other third-party, off-the-shelf-solutions.