International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Streamlined blockchains: A simple and elegant approach (tutorial)

Elaine Shi , Cornell University
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Honor: Invited talk
Abstract: A blockchain protocol (also called state machine replication) allows a set of nodes to agree on an ever-growing, linearly ordered log of transactions. In this tutorial, we present a new paradigm called “streamlined blockchains”. This paradigm enables a new family of protocols that are extremely simple and natural: every epoch, a proposer proposes a block extending from a notarized parent chain, and nodes vote if the proposal’s parent chain is not too old. Whenever a block gains enough votes, it becomes notarized. Whenever a node observes a notarized chain with several blocks of consecutive epochs at the end, then the entire chain chopping off a few blocks at the end is final. By varying the parameters highlighted in blue, we illustrate two variants for the partially synchronous and synchronous settings respectively. We present very simple proofs of consistency and liveness. We hope that this tutorial provides a compelling argument why this new family of protocols should be used in lieu of classical candidates (e.g., PBFT, Paxos, and their variants), both in practical implementation and for pedagogical purposes.
  title={Streamlined blockchains: A simple and elegant approach (tutorial)},
  note={Invited talk},
  author={Elaine Shi},