Organizer: Kristina Hostakova, Prof. Sebastian Faust (TU Darmstadt)
State channels are a leading approach for improving the scalability of blockchains and cryptocurrencies. They allow a group of distrustful parties to optimistically execute an application-defined program amongst themselves, while the blockchain serves as a backstop in case of a dispute or abort. This effectively bypasses the congestion, fees and performance constraints of the underlying blockchain in the typical case. However, state channels introduce a new and undesirable assumption that a party must remain on-line and synchronised with the blockchain at all times to defend against execution fork attacks. An execution fork can revert a state channel’s history, potentially causing financial damage to a party that is innocent except for having crashed. To provide security even to parties that may go off-line for an extended period of time, we present Pisa, a protocol enables such parties to delegate to a third party, called the custodian, to cancel execution forks on their behalf. To evaluate Pisa, we provide a proof-of-concept implementation for a simplified Sprites and we demonstrate that it is cost-efficient to deploy on the Ethereum network.
Patrick McCorry is a research associate at University College London (UCL) with Sarah Meiklejohn and he will soon join Kings College London (KCL) as an Assistant Professor in the fall. He previously worked at the University of Illinois at Urbana-Champaign (UIUC) with Andrew Miller. He is the UK's first PhD graduate in cryptocurrencies from Newcastle University where he was under the supervision of Feng Hao. His research interests include cryptocurrencies and applied cryptography. In the past, he worked at IBM UK for the CICS (Customer Information Control Systems) portfolio which is used by most banks in the world.