OpenAthens Keystone is middleware that allows you to use the widespread and simple OpenID Connect software to participate in SAML federations around the world and easily allow institutional subscription to your content. SAML and the things that use it, such as Shibboleth, are great but can be complicated beasts to integrate into your systems - OpenID Connect is considerably simpler and you may already be using it.
What is OpenID Connect?
OpenID Connect (or OIDC) was introduced in 2014 by the OpenID Foundation to deliver a more API-friendly way of performing many of the same tasks as OpenID 2.0. This API-friendly approach is what makes it work well within native and mobile applications (as well as OpenAthens. It is, basically, ). If you're familiar with OAuth 2.0, then it's a an authentication layer on top of the OAuth 2.0 that authorisation framework. When you see a log in with Google option on a website, that's OpenID Connect.
There are versions available for all major platforms and many minor ones; most are quite straightforward to implement. If you are already equipped for logins such as Google accounts, you You may already be using it.
How is OpenID Connect different from OpenID or OAuth?