Extending the Strand Space Method with Timestamps: Part I the Theory

Abstract

In this paper, we present two extensions of the strand space method to model Kerberos V. First, we include time and timestamps to model security protocols with timestamps: we relate a key to a crack time and combine it with timestamps in order to define a notion of recency. Therefore, we can check replay attacks in this new framework. Second, we extend the classic strand space theory to model protocol mixture. The main idea is to introduce a new relation a to model the causal relation between one primary protocol session and one of its following secondary protocol session. Accordingly, we also extend the definition of unsolicited authentication test.

Secure time information in the internet key exchange protocol

“…There are many other applications where assurance of an actual time is required. A good example could be Kerberos Protocol [37,38,39], where the time of a server and the time of clients must be synchronized. Our scheme can be applied there: when a client detects that his time is desynchronized, he should synchronize it with a trusted host (server).…”

Formal Verification of Secrecy in Group Key Protocols Using Event-B

“…Dalal et al [20] provided a comparative and evaluation study for tools used in verification of security protocols. In another related work, Li [21] and Pand extended the strand space method to include time and timstamps to model the notion of recency in Kerberos protocol.…”