Choreographies and Cost Semantics for Reliable Communicating Systems

Licentiate thesis, 2020

Communicating systems have become ubiquitous in today's society.
Unfortunately, the complexity of their interactions makes them
particularly prone to failures such as deadlocked states caused
by misbehaving components, or memory exhaustion due to a surge in
message traffic (malicious or not). These vulnerabilities
constitute a real risk to users, with consequences ranging from
minor inconveniences to the possibility of loss of life and
capital. This thesis presents two results that aim to increase
the reliability of communicating systems. First, we implement a
choreography language which by construction can only describe
systems that are deadlock-free. Second, we develop a cost
semantics to prove programs free of out-of-memory errors. Both of
these results are formalized in the HOL4 theorem prover and
integrated with the CakeML verified stack.