He joined Penn State after working for IBM Research for nine years in operating systems and system security research groups. Trent's research interests include operating systems security, access control, and source code and policy analysis tools. He has published over 90 refereed research papers on these subjects. Trent has made a variety of contributions to open source systems security, particularly to the Linux Security Modules framework, the SELinux module and policy development, integrity measurement in Linux, and the Xen security architecture. Trent is the author of the book "Operating Systems Security," which examines the principles and designs of secure