We present CELESTIAL, a framework for formally verifying smart contracts written in the Solidity language for the Ethereum blockchain. CELESTIAL allows programmers to write expressive functional specifications for their contracts. It translates the contracts and the specifications to F⋆ to formally verify, against an F⋆ model of the blockchain semantics, that the contracts meet their specifications. Once the verification succeeds, CELESTIAL performs an erasure of the specifications to generate Solidity code for execution on the Ethereum blockchain. We use CELESTIAL to verify several real-world smart contracts from different application domains. Our experience shows that CELESTIAL is a valuable tool for writing high-assurance smart contracts.

We study the problem of enforcing information flow control (IFC) in ehealth systems to verify secure flow of information through programs. IFC mechanisms allow users to control the release and propagation of sensitive information so that confidential information is not observable to unintended principals while collaborating with other legitimate principals. We formalise the parametrised security classes that are required for security policy specification in typical e-health systems in a hospital and use static type checking for detecting security policy violations in the system. The key advantage of using the parametrised security class lattice is greater precision in stating policies, enhanced usability and a reduced overhead in creating security tags.