We are doing a security review of the ArcGIS Portal for Server 10.3 environment. We currently have a sandbox Portal environment setup on some developement/test servers in house. One of my security guys asked me where the Portal user and security information is stored. I did not know the answer, I assumed that it was some sort of flat file on the server somewhere.
When a user visits our Portal for the first time, a named user account is created for them. That appears to be Portal data right (not ArcGIS server data). I did some casual searching, but I could not determine where this data is being stored. Can someone tell me?

Additionally, Portal Groups can be linked to Active Directory groups. Do you know where that data is stored too?

Thank you.
--Rick