"Operating Blockchains Near Physical Limits"
Speaker: David Tse
David N.C. Tse is the Thomas Kailath and Guanghan Xu Professor of Engineering at Stanford University. He received his B.A.Sc. in Systems Design Engineering from the University of Waterloo, and his M.S. and Ph.D. degrees from the Massachusetts Institute of Technology. Tse is a world-leading authority in information theory, particularly for his contributions to wireless communication, energy and computational biology. An IEEE Fellow, Tse is recipient of numerous awards, including the IEEE ITS Claude E. Shannon Award, the IEEE Communications Society Stephen O. Rice Prize and the INFORMS Applied Probability Society Erlang Prize. He was inducted into the U.S. National Academy of Engineering in 2018.
The concept of a blockchain was invented by Satoshi Nakamoto to maintain a distributed ledger. In addition to its security, important performance measures of a blockchain protocol are its transaction throughput, confirmation latency and confirmation reliability. These measures are limited by two underlying physical network attributes: communication capacity and speed-of-light propagation delay. Existing systems operate far away from these physical limits. In this work we introduce Prism, a new blockchain protocol, which can provably achieve
- security against up to 50% adversarial hashing power;
- optimal throughput up to the capacity C of the network;
- confirmation latency for honest transactions proportional to the propagation delay D, with confirmation error probability exponentially small in the bandwidth-delay product CD;
- eventual total ordering of all transactions.
Our approach to the design of this protocol is based on deconstructing the blockchain into its basic functionalities and systematically scaling up these functionalities to approach their physical limits.
This is joint work with Vivek Bagaria, Sreeram Kannan, Giulia Fanti and Pramod Viswanath. The full paper can be found at https://arxiv.org/abs/1810.08092.