TENET: Towards Self-sovereign and Fair Multi-party Computation Ecology Empowered by Decentralized TEE Network

Recently, blockchain has been adopted across an increasing range of domains, e.g., supply chain finance, digital government. The confidentiality of smart contracts has now become a fundamental and crucial demand for practical applications. However, while new privacy protection techniques are emerging, how to securely enable Multi-party Computation (MPC) in confidential smart contracts is understudied. State-of-the-art solutions suffer on high on-chain cost, low flexibility and security thus can hardly reach general users. This paper proposes TENET, a pluggable and configurable confidential smart contract framework. TENET identifies the pitfalls for supporting off-chain MPC-enabled confidential smart contracts by leveraging the TEE network and proposes corresponding treats, e.g., anonymously negotiate MPC among apriori-unknown participants, atomically and fairly distribute the MPC outputs, and securely evaluate an MPC program with constant on-chain transactions. TENET manages to secure an MPC by only 3 transactions. In our evaluation on both examples and real-world applications involving 2 to 11 parties, TENET costs 0.55-0.98X gas (0.91X on average) against the state-of-the-art.