Strand Space Theory Research Articles

Fairness Analysis for Multiparty Nonrepudiation Protocols Based on Improved Strand Space

Aimed at the problem of the fairness analysis for multiparty nonrepudiation protocols, a new formal analysis method based on improved strand space is presented. Based on the strand space theory, signature operation is added; the set of terms, the subterm relation and the set of penetrator traces are redefined and the assumption of free encryption is extended in the new method. The formal definition of fairness in multi-party non-repudiation protocols is given and the guideline to verify it based on improved strand space is presented. Finally, the fairness of multi-party non-repudiation protocols is verified with an example of Kremer-Markowitch protocol, which indicates that the new method is suitable for analyzing the fairness of multiparty nonrepudiation protocols.

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

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 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.

Dynamic security analysis of group key agreement protocol

Group key agreement is a fundamental building block for increasing collaborative applications. The protocol is more complicated than peer-to-peer communication owing to its dynamic characteristics, but the research to date on group key agreement protocols (GKAP) mainly focuses on the static security and the most distinctively dynamic characteristic of GKAP is difficult to analyse by existing methods. The paper attempts to extend the strand space theory to analyse the dynamic security of GKAP. With the aid of the theory, the AT-GDH protocol is taken as an example to discuss the general conditions of the security retention in dynamic cases. A new scheme is proposed of updating the session key when some member leaves the group based on SA-GDH.2 protocol to avoid the single-point weakness.

Authentication tests and disjoint encryption: A design method for security protocols*

We describe a protocol design process, and illustrate its use by creating ATSPECT, an Authentication Test-based Secure Protocol for Electronic Commerce Transactions. The design process is organized around the authentication tests, a method for protoc