9753055 Landau, Susan University of Massachusetts POWRE: Certification of Security Protocols This research involves security properties of protocols and other systems that are built with cryptographic techniques. Investigators look at two principal issues; the first is ``protocol busting,'' which studies how complex protocols built from other pieces (such as secure cryptographic systems) can become insecure through misuse of the cryptographic pieces or through unwarranted assumptions about them. The second issue being tackled is developing methods to certify security properties. Research in protocol-busting involves the examination of proposed password-based session-key agreement protocols, and studies characterizations under which an authentication scheme can safely incorporate a small shared piece of secret information (e.g. a password). The investigators develop protocols for multi-user authentication when the group is large and in flux; techniques include graph-theoretic and algebraic methods. The investigator is studying certification schemes of cryptosystems for authentication in a distributed network. Developing a certification scheme means developing a logical framework for the various types of attacks that have arisen on cryptosystems, and then developing a suite of appropriate tests. The distributed algorithms work concerns developing protocols to delegate authority in a multi-user environment.
