> For the complete documentation index, see [llms.txt](https://shoppinpal.gitbook.io/docs-shoppinpal-com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://shoppinpal.gitbook.io/docs-shoppinpal-com/appendix/authentication-principles.md).

# Authentication Principles

Simple [introduction](http://merbist.com/2012/04/04/building-and-implementing-a-single-sign-on-solution/) to SSO (single-sign-on).

OAuth is [**not**](https://stormpath.com/blog/oauth-is-not-sso) Single-Sign-On