Casey Schaufler worked on Unix kernels in the 1970s-90s. He has implemented access control lists, mandatory access control, extended filesystem attributes, X11 access controls, network protocols and more audit systems than is really healthy. His involvement in Linux began with the Linux Security Module work at the turn of the century, introducing the Smack LSM in 2007. Casey is reworking the LSM infrastructure to support multiple concurrent modules. He has spoken at LCA, OLS, and many venues.