CONTENTS - Emerald

lock chaining in such a way that protocol element boundaries coincide with cipher
block boundaries.
041424 `A Calculus for Secure Channel Establishment in Open Networks'
UM Maurer, PE Schmid, ESORICS 94 pp 175{192
The authors introduce a new notation to help visualise the security relationships
in a network: A ! B means that A can send a secret message to B, while A ! B
means that A can send an authentic message to B. They develop a set of formal rules
and show that, under reasonable assumptions, ! is equivalent to . Thus one can
see at a glance whether it is possible to set up a con dential or authenticated channel
between two nodes in a network, by looking for a path between them in which the
bullets are all at the same end.
041425 `Formal Veri cation of Cryptographic Protocols: A Survey'
CA Meadows, Asiacrypt 94 pp 117{130
The author gives an overview of the formal techniques used to analyse crypto
protocols. She covers state machine methods, such as Millen's Interrogator and the
NRL Protocol Analyser, both based on the Dolev-Yao model; modal logics such as
BAN; and algebraic approaches such as those of Merritt and Toussaint. She discusses
the problems of protocol idealisation and of model granularity, and considers how formal
methods can be used in the design phase to clarify requirements.
041426 `Application Access Control at Network Level'
R Molva,ERutschke, Fairfax 94 pp 219{228
The authors discuss a mechanism whereby applications use a secure protocol stack
to insert precomputed tickets into packets, and any packets without them are killed at
a rewall. This enables network layer enforcement of application level security policies.
An implementation in IP is described; it is suggested that mechanisms of this kind are
ideal for securing multicast channels, especially against ooding attacks.
041427 `Prerequisite Con dentiality'
JP Nestor, ES Lee, Fairfax 94 pp 282{293
The authors propose a new de nition of con dentiality inmultilevel systems, which
is based on formal modelling by event systems and deterministic regular parsable grammars.
The goal is to build a structure in which composability can be dealt with in a
coherent and rigorous manner. Like Lin's behavioural security model, it is based on
input-output causality and requires that high-level input events never be prerequisites
for low-level output events.
041428 `Secure Agreement Protocols: Reliable and Atomic Group Multicast
in Rampart'
MK Reiter, Fairfax 94 pp 68{80
The author presents new protocols which ensure that all honest members of a group
deliver the same messages in the same order, and describes their implementation in a
toolkit for building high-integrity distributed services. They are based on the author's
secure group membership protocol, and the basic building block isecho multicast: a
single member publishes a message | sends it to all group members | gets their answers,
and publishes these too. It thus gets round the traditional problem of telling
whether a group member is dishonest or merely unreachable, and therefore makes secure
multicast protocols feasible in loosely-coupled asynchronous systems. Performance
measurements for a trial implementation are given.
041429 `A Consideration of the Modes of Operation for Secure Systems'
CL Robinson, SR Wiseman, ESORICS 94 pp 335{356
The authors examine the UK's modes of system operation (dedicated, system high,
compartmented and multilevel) and present of formal model in Z of the underlying
rules. This was of bene t because it forced the authors to examine the di cult aspects
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