10 research outputs found
Multi-agent system security for mobile communication
This thesis investigates security in multi-agent systems for mobile communication.
Mobile as well as non-mobile agent technology is addressed.
A general security analysis based on properties of agents and multi-agent systems
is presented along with an overview of security measures applicable to
multi-agent systems, and in particular to mobile agent systems.
A security architecture, designed for deployment of agent technology in a mobile
communication environment, is presented. The security architecture allows
modelling of interactions at all levels within a mobile communication system.
This architecture is used as the basis for describing security services and mechanisms
for a multi-agent system. It is shown how security mechanisms can be
used in an agent system, with emphasis on secure agent communication.
Mobile agents are vulnerable to attacks from the hosts on which they are executing.
Two methods for dealing with threats posed by malicious hosts to a
trading agent are presented. The rst approach uses a threshold scheme and
multiple mobile agents to minimise the eect of malicious hosts. The second
introduces trusted nodes into the infrastructure.
Undetachable signatures have been proposed as a way to limit the damage a
malicious host can do by misusing a signature key carried by a mobile agent.
This thesis proposes an alternative scheme based on conventional signatures and
public key certicates.
Threshold signatures can be used in a mobile agent scenario to spread the risk
between several agents and thereby overcome the threats posed by individual
malicious hosts. An alternative to threshold signatures, based on conventional
signatures, achieving comparable security guarantees with potential practical
advantages compared to a threshold scheme is proposed in this thesis.
Undetachable signatures and threshold signatures are both concepts applicable
to mobile agents. This thesis proposes a technique combining the two schemes
to achieve undetachable threshold signatures.
This thesis denes the concept of certicate translation, which allows an agent
to have one certicate translated into another format if so required, and thereby
save storage space as well as being able to cope with a certicate format not
foreseen at the time the agent was created
On the value of threshold signatures
Threshold signature schemes are examples of threshold cryptosystems, as introduced by Desmedt, [4]. The purpose of this paper is to present a rather simple alternative to threshold signatures which raises questions about the value of such schemes, at least when applied to the mobile agent scenario
A pragmatic alternative to undetectable signatures
A 'pragmatic' alternative to undetachable signatures is proposed. Undetachable signatures were introduced by Sander and Tschudin, [4], as a means of giving a mobile agent the means to sign a message on behalf of a user, without endangering the user's private key. The alternative discussed in this paper involves the use of conventional signatures and public key certificates