Robert N. M. Watson <>

Trusted operating systems provide a “next level” of system security, offering both new security features and higher assurance that they are properly implemented. TrustedBSD is an ongoing project to integrate a number of trusted OS features into the open source FreeBSD operating system, and involves both architectural and development process improvements. This paper describes how the opensource development practices of the FreeBSD Project impacted the design and implementation choices for these features, and describes lessons learned that will influence future work. Several key TrustedBSD features are discussed as examples of how new security services may be introduced in such an enviroment.