Outsourcing computation is motivated in numerous settings including when a weak client wants to outsource its computation to a powerful computing agent (e.g. cloud), or when the client’s goal is to distribute its computation among multilpe volunteer helpers and obtain the final result by combing the partial result of each helper. In all these cases an important challenge for the client is to efficiently verify the correctness of the computation result that could have been changed intentionally or by accident. Systems such as Trubit use smart contracts to automate outsourcing of computation, and act as a transparent trusted party to handle partial computation results, and manage the payments. In this talk we show security challenges of these systems, look at two verifiable computation systems that are mediated by smart contracts, show concrete attacks on these systems and propose methods of securing them.

Bio: Rei Safavi-Naini is the NSERC/Telus Industrial Research Chair and Alberta Innovates Strategic Research Chair in Information Security at the University of Calgary. She is the co- founder of the Institute for Security, Privacy and Information Assurance at the University, and served as its Director until December 2018. She has published widely in premier journals and conferences on information security and privacy and has given numerous keynote talks, most recently at Chinacrypt 2018 and Privacy, Security and Trust 2019. She has served on the editorial board of leading information security journals and program committee of conferences, and has been the program chair of major international conferences including Crypto, Financial Cryptography, and Applied Cryptography and Network Security. She is currently Associate Editor of IEEE Transactions on Information Theory, IET Information Security and Journal of Mathematical Cryptology. Her current research interest includes post-quantum cryptography and communicationsecurity, cloud security, and security of blockchain and decentralized systems