Paper 2007/188 Original: eprint.iacr.org/2007/188 ↗

A Proof of Revised Yahalom Protocol in the Bellare and Rogaway (1993) Model

Abstract

Although the Yahalom protocol, proposed by Burrows, Abadi, and Needham in 1990, is one of the most prominent key establishment protocols analyzed by researchers from the computer security community (using automated proof tools), a simplified version of the protocol is only recently proven secure by Backes and Pfitzmann (2006) in their \textit{cryptographic library} framework. We present a protocol for key establishment that is closely based on the Yahalom protocol. We then present a security proof in the Bellare and Rogaway (1993) model and the random oracle model. We also observe that no partnering mechanism is specified within the Yahalom protocol. We then present a brief discussion on the role and the possible construct of session identifiers as a form of partnering mechanism, which allows the right session key to be identified in concurrent protocol executions. We then recommend that session identifiers should be included within protocol specification rather than consider session identifiers as artefacts in protocol proof.