An Approach to Formalise Blockchain Interoperability Patterns

Developing blockchain interoperability solutions is costly and complex. Designers must ensure that their decisions comply with the required safety and liveness properties. A recent study proposed six blockchain interoperability design patterns to facilitate this development. However, they were informally described using natural language, which can lead to ambiguity and misinterpretation. The present study proposes to explore the use of Event-B to formalise the Temporal Transfer pattern, instantiated using a gateway-based approach, with the aim of solving these drawbacks. As a result, a formal specification was built that included eight safety properties. The specification was evaluated through formal verification and functional validation. The evaluation showed that the specification was correct by construction and all specified safety properties were verified. Furthermore, simulation enabled us to validate the functional behaviour of the specification. We consider the results of the present study promising and that they constitute a step forward in the formalisation of blockchain interoperability patterns.