  Distributed system architectures such as cloud computing or the emergent
architectures of the Internet Of Things, present significant challenges for
security and privacy. Specifically, in a complex application there is a need to
securely delegate access control mechanisms to one or more parties, who in turn
can govern methods that enable multiple other parties to be authenticated in
relation to the services that they wish to consume. We identify shortcomings in
an existing proposal by Xu et al for multiparty authentication and evaluate a
novel model from Al-Aqrabi et al that has been designed specifically for
complex multiple security realm environments. The adoption of a Session
Authority Cloud ensures that resources for authentication requests are
scalable, whilst permitting the necessary architectural abstraction for myriad
hardware IoT devices such as actuators and sensor networks, etc. In addition,
the ability to ensure that session credentials are confirmed with the relevant
resource principles means that the essential rigour for multiparty
authentication is established.
