The Antigone software system defines a framework for the flexible definition and implementation of security policies in group communication systems. Antigone does not dictate the available security policies, but provides high-level mechanisms for implementing them. A central element of the Antigone architecture is a suite of such mechanisms comprising micro-protocols that provide the basic services needed by secure groups. Policies are implemented through the composition and configuration of these mechanisms. Mechanisms are composed in different ways to address new requirements and environ-mental constraints. The Antigone framework provides an easy-to-use application programming interface (API), from which secure group application programs can be built. Written entirely in the C++ programming language, the system consists of over 18,000 lines of source code and has been ported to several versions of Linux, FreeBSD, and SunOS. Information for accessing recent versions of the source code and related documentation is available at

This program was written by Patrick McDaniel and Atul Prakash of the University of Michigan for Kennedy Space Center. In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to: Electrical Engineering and Computer Sciences Department University of Michigan 3115 EECS 1301 Beal Ave. Ann Arbor, MI 48109 Refer to KSC-12207, volume and number of this NASA Tech Briefs issue, and the page number.