Streamlet: Textbook Streamlined Blockchains

In the past five years or so, numerous blockchain projects have made tremendous progress towards improving permissioned consensus protocols (partly due to their promised applications in Proof-of-Stake cryptocurrencies). Although a significant leap has silently taken place in our understanding of consensus protocols, it is rather difficult to navigate this body of work, and knowledge of the new techniques appears scattered. In this paper, we describe an extremely simple and natural paradigm called Streamlet for constructing consensus protocols. Our protocols are inspired by the core techniques that have been uncovered in the past five years of work; but to the best of our knowledge our embodiment is simpler than ever before and we accomplish this by taking a "streamlining" idea to its full potential. We hope that our textbook constructions will help to decipher the past five years of work on consensus partly driven by the cryptocurrency community --- in particular, how remarkably simple the new generation of consensus protocols has become in comparison with classical mainstream approaches such as PBFT and Paxos.

[1]  Elaine Shi,et al.  PaLa: A Simple Partially Synchronous Blockchain , 2018, IACR Cryptol. ePrint Arch..

[2]  Elaine Shi,et al.  Hybrid Consensus: Efficient Consensus in the Permissionless Model , 2016, DISC.

[3]  Butler W. Lampson,et al.  The ABCD's of Paxos , 2001, PODC '01.

[4]  Elaine Shi,et al.  Rethinking Large-Scale Consensus , 2017, 2017 IEEE 30th Computer Security Foundations Symposium (CSF).

[5]  Aggelos Kiayias,et al.  The Bitcoin Backbone Protocol: Analysis and Applications , 2015, EUROCRYPT.

[6]  Jae Kwon,et al.  Tendermint : Consensus without Mining , 2014 .

[7]  Abhi Shelat,et al.  Analysis of the Blockchain Protocol in Asynchronous Networks , 2017, EUROCRYPT.

[8]  Vitalik Buterin,et al.  Casper the Friendly Finality Gadget , 2017, ArXiv.

[9]  Dominic Williams,et al.  DFINITY Technology Overview Series, Consensus System , 2018, ArXiv.

[10]  Kartik Nayak,et al.  Sync HotStuff: Simple and Practical Synchronous State Machine Replication , 2020, 2020 IEEE Symposium on Security and Privacy (SP).

[11]  Ramakrishna Kotla,et al.  Zyzzyva , 2007, SOSP.

[12]  Elaine Shi,et al.  Snow White: Provably Secure Proofs of Stake , 2016, IACR Cryptol. ePrint Arch..

[13]  Nancy A. Lynch,et al.  Consensus in the presence of partial synchrony , 1988, JACM.

[14]  Robbert van Renesse,et al.  Paxos Made Moderately Complex , 2015, ACM Comput. Surv..

[15]  Leslie Lamport,et al.  The Byzantine Generals Problem , 1982, TOPL.

[16]  Leslie Lamport,et al.  Paxos Made Simple , 2001 .

[17]  Jean-Philippe Martin,et al.  Fast Byzantine Consensus , 2006, IEEE Transactions on Dependable and Secure Computing.

[18]  Elaine Shi,et al.  Streamlined Blockchains: A Simple and Elegant Approach (A Tutorial and Survey) , 2019, ASIACRYPT.

[19]  Aggelos Kiayias,et al.  Ouroboros: A Provably Secure Proof-of-Stake Blockchain Protocol , 2017, CRYPTO.

[20]  Fred B. Schneider,et al.  Implementing fault-tolerant services using the state machine approach: a tutorial , 1990, CSUR.

[21]  Ittai Abraham,et al.  HotStuff: BFT Consensus with Linearity and Responsiveness , 2019, PODC.

[22]  Elaine Shi,et al.  PiLi: An Extremely Simple Synchronous Blockchain , 2018, IACR Cryptol. ePrint Arch..

[23]  Ittai Abraham,et al.  Hot-Stuff the Linear, Optimal-Resilience, One-Message BFT Devil , 2018, ArXiv.

[24]  John K. Ousterhout,et al.  In Search of an Understandable Consensus Algorithm , 2014, USENIX Annual Technical Conference.

[25]  Miguel Oom Temudo de Castro,et al.  Practical Byzantine fault tolerance , 1999, OSDI '99.

[26]  Marko Vukolic,et al.  The Next 700 BFT Protocols , 2015, ACM Trans. Comput. Syst..

[27]  Silvio Micali,et al.  ALGORAND: The Efficient and Democratic Ledger , 2016, ArXiv.

[28]  Leslie Lamport,et al.  The part-time parliament , 1998, TOCS.

[29]  Satoshi Nakamoto.  Bitcoin : A Peer-to-Peer Electronic Cash System , 2009 .

[30]  Elaine Shi,et al.  PiLi : A Simple , Fast , and Robust Family of Blockchain Protocols ∗ , 2019 .

[31]  Elaine Shi,et al.  Snow White: Robustly Reconfigurable Consensus and Applications to Provably Secure Proof of Stake , 2019, Financial Cryptography.