  Collective remote attestation (CRA) is a security service that aims to
efficiently identify compromised (often low-powered) devices in a
(heterogeneous) network. The last few years have seen an extensive growth in
CRA protocol proposals, showing a variety of designs guided by different
network topologies, hardware assumptions and other functional requirements.
However, they differ in their trust assumptions, adversary models and role
descriptions making it difficult to uniformly assess their security guarantees.
In this paper we present Catt, a unifying framework for CRA protocols that
enables them to be compared systematically, based on a comprehensive study of
40 CRA protocols and their adversary models. Catt characterises the roles that
devices can take and based on these we develop a novel set of security
properties for CRA protocols. We then classify the security aims of all the
studied protocols. We illustrate the applicability of our security properties
by encoding them in the tamarin prover and verifying the SIMPLE+ protocol
against them.
