  This paper introduces a scalable and secure contract-enforcement mechanism,
called Cop, which can be applied to a broad range of multi-agent systems
including small and large systems, time-critical systems, and
systems-of-systems. Cop enforces contracts (or protocols) via the existing Law-
Governed Interaction (LGI) mechanism, coupled with a new protective layer that
significantly enhances the dependability and security of such enforcement. Cop
is arguably superior to the currently popular blockchain-based smart-contract
mechanisms, due to its scalability, interoperability, and the breadth of the
spectrum of its domain of applications.
