OAuth is an open standard for authorization. OAuth provides client applications a 'secure delegated access' to server resources on behalf of a resource owner. It specifies a process for resource owners to authorize third-party access to their server resources without sharing their credentials.

 

 

OAuth and the Rehydrated User in SharePoint 2013 GP0|#f573dc2f-c5f4-41fa-a51a-97d9709762c7;L0|#0f573dc2f-c5f4-41fa-a51a-97d9709762c7|OAuth;GTSet|#68e31ecf-dbe9-45e0-8a3c-fc6bd6ad0ce6;GPP|#6553c9ac-7cd3-4c35-9ee0-494641495101;GPP|#1b064965-36f6-40b1-a474-78053852e564;GPP|#74f9ea2a-fcec-489f-9ca4-da563b559213 ​Why inter-farm service application authentication requires users to be in the User Profile Service.
Inside SharePoint 2013 OAuth Context TokensGP0|#f573dc2f-c5f4-41fa-a51a-97d9709762c7;L0|#0f573dc2f-c5f4-41fa-a51a-97d9709762c7|OAuth;GTSet|#68e31ecf-dbe9-45e0-8a3c-fc6bd6ad0ce6;GPP|#6553c9ac-7cd3-4c35-9ee0-494641495101;GPP|#1b064965-36f6-40b1-a474-78053852e564;GPP|#74f9ea2a-fcec-489f-9ca4-da563b559213;GP0|#afeedca3-6eba-4b1c-9465-f1b1f76d3e3d;L0|#0afeedca3-6eba-4b1c-9465-f1b1f76d3e3d|Apps;GPP|#a5205c2f-ad79-446f-8d9e-afd0eeecf427 ​This post will show you how to inspect the SharePoint 2013 context token to better understand how OAuth is used in SharePoint 2013 apps