Es handelt sich um eine recht umfangreiche Spezifikation, und sie deckt mehrere komplexe Anwendungsfälle ab.

Sie umfasst Möglichkeiten zur Authentifizierung mithilfe eines „Dritten“ („third party“).

Das ist es, was alle diese „Login mit Facebook, Google, Twitter, GitHub“-Systeme unter der Haube verwenden.

### OAuth 1

OAuth2 is a specification that defines several ways to handle authentication and authorization.

It is quite an extensive specification and covers several complex use cases.

It includes ways to authenticate using a "third party".

That's what all the systems with "login with Facebook, Google, Twitter, GitHub" use underneath.

### OAuth 1

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