Explore a conference talk from CCS 2016 that presents a secure sharding protocol for open blockchains. Delve into the scalability challenges faced by existing blockchain protocols and discover innovative solutions proposed by researchers from the National University of Singapore. Learn about the straw-man solution for sharding, its analysis, and the introduction of a directory committee to address security concerns. Examine the process of generating epoch randomness and evaluate the performance of Elastico, the proposed protocol, in terms of scalability, bandwidth, and message efficiency. Gain insights into cutting-edge research aimed at improving the scalability and security of open blockchain systems.