Rhino Security is a security framework to provide row level security for NHibernate. Rhino Security is perfect for people who want to set up user and group security in their NHibernate domain models. It supports ACL and role based security using a model similar to this:
Based on this blog post
Read the How to Use.txt file for more information about getting started.
More information about the library can be found in the Rhino Security category on Ayende's blog.
Try this Google search to find a ton of other information about it.
Intro by Tobin Harris, he askes that people contribute to make it better :)