Demystifying Blockchains: Decentralized and Fault-Tolerant Storage for the Future of Big Data? (Keynote Lecture)

Bitcoin is a successful and interesting example of a global scale peer-to-peer cryptocurrency that integrates many techniques and protocols from cryptography, distributed systems, and databases. The main underlying data structure is blockchain, a scalable fully replicated structure that is shared among all participants and guarantees a consistent view of all user transactions by all participants in the cryptocurrency system. The novel aspect of Blockchain is that historical data about all transactions is maintained in the absence of any central authority. This property of Blockchain has given rise to the possibility that future applications will transition from centralized databases to a fully decentralized storage based on blockchains. In this talk, we start by developing an understanding of the basic protocols used in blockchain, and elaborate on their main advantages and limitations. To overcome these limitations, we will explore some of the challenges of managing large scale fully replicated ledgers in the context of achieving large scale consensus. Finally, we ponder over recent efforts to use blockchains in diverse applications.