... e-mail: hakanh@acm.orgMarios HadjileftheriouAT&T Labs Inc., e-mail: marioh@research.att.comRagib HasanDepartment of Computer Science, University of Illinois at Urbana-Champaign, IL,e-mail: ... School of Computer Science, University of California, Irvine, CA,e-mail: sharad@ics.uci.eduSoumyadeb MitraDepartment of Computer Science, University of Illinois at Urbana-Champaign, IL,e-mail: ... denoted c1≥ c2,iffthe security level of c1is greater than or equal to the security level of c2andthe set of categories of c1includes the set of categories of c2. Access classestogether...