Looking for FOSS winforms authentication framework

[sklett]

Apologies for the off-topic

I need to bring my application into ISO 13485 compliance and need to
overhaul or user authentication and management system. Before I start
designing I thought I would check if anyone knows of a open source project
out there? Something like NUnit, Log4net, etc.

I did some googling but didn't come up with much...

Thanks for any suggestions,
Steve