Tim Roughgarden+

Synchronous Byzantine Fault Tolerance (Kartik Nayak)

Speaker: Kartik Nayak (Duke University) Title: Synchronous Byzantine Fault Tolerance Event: 2026 Summer School on the Theory & Practice of Blockchain Consensus, presented by the Columbia-Ethereum Center on Blockchain Protocol Design. Full playlist: https://www.youtube.com/playlist?list=PLE3feiVojazU Summer school website: https://timroughgarden.org/summerschool26.html

Accountability (Joachim Neu)

Speaker: Joachim Neu (a16z crypto) Title: Accountability Event: 2026 Summer School on the Theory & Practice of Blockchain Consensus, presented by the Columbia-Ethereum Center on Blockchain Protocol Design. Full playlist: https://www.youtube.com/playlist?list=PLE3feiVojazU Summer school website: https://timroughgarden.org/summerschool26.html

The Anatomy of a Blockchain (Patrick O'Grady)

Speaker: Patrick O'Grady (Commonware) Title: The Anatomy of a Blockchain Event: 2026 Summer School on the Theory & Practice of Blockchain Consensus, presented by the Columbia-Ethereum Center on Blockchain Protocol Design. Full playlist: https://www.youtube.com/playlist?list=PLE3feiVojazU Summer school website: https://timroughgarden.org/summerschool26.html

DAG-Based Consensus: Introduction and Practical Aspects (Alberto Sonnino)

Speaker: Alberto Sonnino (Mysten Labs) Title: DAG-Based Consensus: Introduction and Practical Aspects Event: 2026 Summer School on the Theory & Practice of Blockchain Consensus, presented by the Columbia-Ethereum Center on Blockchain Protocol Design. Full playlist: https://www.youtube.com/playlist?list=PLE3feiVojazU Summer school website: https://timroughgarden.org/summerschool26.html

Encrypted Mempools and Batched Threshold Encryption (Guru Vamsi Policharla)

Speaker: Guru Vamsi Policharla (Commonware) Title: Encrypted Mempools and Batched Threshold Encryption Event: 2026 Summer School on the Theory & Practice of Blockchain Consensus, presented by the Columbia-Ethereum Center on Blockchain Protocol Design. Full playlist: https://www.youtube.com/playlist?list=PLE3feiVojazU Summer school website: https://timroughgarden.org/summerschool26.html

Distributed Key Generations: Definitions, Constructions, and Applications (Sourav Das)

Speaker: Sourav Das (Category Labs) Title: Distributed Key Generations: Definitions, Constructions, and Applications Event: 2026 Summer School on the Theory & Practice of Blockchain Consensus, presented by the Columbia-Ethereum Center on Blockchain Protocol Design. Full playlist: https://www.youtube.com/playlist?list=PLE3feiVojazU Summer school website: https://timroughgarden.org/summerschool26.html

Introduction to Ethereum Consensus (Part 2 of 2) (Francesco d'Amato and Yann Vonlanthen)

Speakers: Francesco d'Amato and Yann Vonlanthen (Ethereum Foundation) Title: Introduction to Ethereum Consensus (Part 2 of 2) Event: 2026 Summer School on the Theory & Practice of Blockchain Consensus, presented by the Columbia-Ethereum Center on Blockchain Protocol Design. Full playlist: https://www.youtube.com/playlist?list=PLE3feiVojazU Summer school website: https://timroughgarden.org/summerschool26.html

Introduction to Ethereum Consensus (Part 1 of 2) (Francesco d'Amato and Yann Vonlanthen)

Speakers: Francesco d'Amato and Yann Vonlanthen (Ethereum Foundation) Title: Introduction to Ethereum Consensus (Part 1 of 2) Event: 2026 Summer School on the Theory & Practice of Blockchain Consensus, presented by the Columbia-Ethereum Center on Blockchain Protocol Design. Full playlist: https://www.youtube.com/playlist?list=PLE3feiVojazU Summer school website: https://timroughgarden.org/summerschool26.html

Everlasting BFT: How Changing Requirements Keep Reinventing Consensus (Sasha Spiegelman)

Speaker: Sasha Spiegelman (Aptos Labs) Title: Everlasting BFT: How Changing Requirements Keep Reinventing Consensus Event: 2026 Summer School on the Theory & Practice of Blockchain Consensus, presented by the Columbia-Ethereum Center on Blockchain Protocol Design. Full playlist: https://www.youtube.com/playlist?list=PLE3feiVojazU Summer school website: https://timroughgarden.org/summerschool26.html

2-Round Finality (Andrew Lewis-Pye)

Speaker: Andrew Lewis-Pye (LSE / Commonware) Title: 2-Round Finality Event: 2026 Summer School on the Theory & Practice of Blockchain Consensus, presented by the Columbia-Ethereum Center on Blockchain Protocol Design. Full playlist: https://www.youtube.com/playlist?list=PLE3feiVojazU Summer school website: https://timroughgarden.org/summerschool26.html

The Network Beneath the “Computer in the Sky” (Maria Apostolaki)

Speaker: Maria Apostolaki (Princeton University) Title: The Network Beneath the “Computer in the Sky” Event: 2026 Summer School on the Theory & Practice of Blockchain Consensus, presented by the Columbia-Ethereum Center on Blockchain Protocol Design. Full playlist: https://www.youtube.com/playlist?list=PLE3feiVojazU Summer school website: https://timroughgarden.org/summerschool26.html

Longest-Chain Consensus: Safety under Network Delays (Dongning Guo)

Speaker: Dongning Guo (Northwestern University) Title: Longest-Chain Consensus: Safety under Network Delays Event: 2026 Summer School on the Theory & Practice of Blockchain Consensus, presented by the Columbia-Ethereum Center on Blockchain Protocol Design. Full playlist: https://www.youtube.com/playlist?list=PLE3feiVojazU Summer school website: https://timroughgarden.org/summerschool26.html

Reinventing Solana: Alpenglow and Constellation (Roger Wattenhofer)

Speaker: Roger Wattenhofer (ETH Zurich and Anza) Title: Reinventing Solana: Alpenglow and Constellation Event: 2026 Summer School on the Theory & Practice of Blockchain Consensus, presented by the Columbia-Ethereum Center on Blockchain Protocol Design. Full playlist: https://www.youtube.com/playlist?list=PLE3feiVojazU Summer school website: https://timroughgarden.org/summerschool26.html

Many Variants of Simplex (Ittai Abraham)

Speaker: Ittai Abraham (a16z crypto) Title: Many Variants of Simplex Event: 2026 Summer School on the Theory & Practice of Blockchain Consensus, presented by the Columbia-Ethereum Center on Blockchain Protocol Design. Full playlist: https://www.youtube.com/playlist?list=PLE3feiVojazU Summer school website: https://timroughgarden.org/summerschool26.html

2026 Summer School on Theory & Practice of Blockchain Consensus (Opening remarks by Tim Roughgarden)

Speaker: Tim Roughgarden (Columbia University & a16z crypto) Title: Opening Remarks Event: 2026 Summer School on the Theory & Practice of Blockchain Consensus, presented by the Columbia-Ethereum Center on Blockchain Protocol Design. Full playlist: https://www.youtube.com/playlist?list=PLE3feiVojazU Summer school website: https://timroughgarden.org/summerschool26.html

New research center focused on blockchain infrastructure @columbiaseas.bsky.soci

New research center focused on blockchain infrastructure @columbiaseas.bsky.social ! Made possible by @ethereumfoundation.bsky.social . Super-excited about this, more to come!

Announcing the Columbia-Ethereum Research Center on Blockchain Protocol Design

The Columbia-Ethereum Research Center for Blockchain Protocol Design supports research and education to advance the development and understanding of blockchain protocols and their applications. The Center's activities include: 1. Research grants: Much of the center's funds will be used to fund research carried out by Columbia faculty, students, and their collaborators. Proposals from all areas relevant to the infrastructure layer of blockchain protocols are welcome, including the science, engineering, and economics of the networking, consensus, and execution layers of the blockchain stack. 2

Accountable Liveness

Speaker: Tim Roughgarden (Columbia University/a16z crypto) Co-authors: Andrew Lewis-Pye (London School of Economics), Joachim Neu (a16z crypto), Luca Zanolini (Ethereum Foundation) Paper: https://eprint.iacr.org/2025/693.pdf Tweetstorm: https://x.com/jneu_net/status/1917948064373051436 Abstract: When a blockchain protocol stalls (i.e., suffers a liveness violation), which validators should be held accountable? This paper defines the notion of accountable liveness and characterizes the assumptions under which it can be attained by protocols that are optimally resilient in partial synchrony: an

Start here: m.youtube.com/watch?v=wiMp...

Start here: m.youtube.com/watch?v=wiMp...

See the old CS364A websites linked here: timroughgarden.org/teaching.html

See the old CS364A websites linked here: timroughgarden.org/teaching.html

🙏🙏🙏 See also full set of video lectures at m.youtube.com/playlist?lis...

🙏🙏🙏 See also full set of video lectures at m.youtube.com/playlist?lis...

Blockchain Protocols and Web3: A Glimpse Under the Hood

Speaker: Tim Roughgarden (https://timroughgarden.org) Abstract: Blockchain technology aspires to combine the general-purpose functionality of a computer with the decentralization of the Internet---in effect, a global shared computer with the Internet as its hardware. A blockchain protocol plays the role of the operating system of this shared virtual machine. Among other applications, this technology enables stronger property rights for things that we buy or create in the digital realm. This video provides a gentle introduction to the inner workings of blockchain protocols, with an emphasis on

microfoundations for the price of anarchy 🔥🔥🔥

microfoundations for the price of anarchy 🔥🔥🔥

Mental Models for Blockchain Protocols and Web3

Speaker: Tim Roughgarden (https://timroughgarden.org) Abstract: Blockchain technology aspires to combine the general-purpose functionality of a computer with the decentralization of the Internet---in effect, a global shared computer with the Internet as its hardware. A blockchain protocol plays the role of the operating system of this shared virtual machine. Among other applications, this technology enables stronger property rights for things that we buy or create in the digital realm. Sequel video (Blockchain Protocols and Web3: A Glimps Under the Hood): https://www.youtube.com/watch?v=-mWj

A thank-you email from a Chinese stutent for Algorithms Illuminated translated i

A thank-you email from a Chinese stutent for Algorithms Illuminated translated in part as "your book is my learning algorithm prairie fire" Not sure what the "correct" translation should be but it can't be any cooler than that

just remembered that one time when Bernard Chazelle proved that, unlike 99.9999%

just remembered that one time when Bernard Chazelle proved that, unlike 99.9999% of humans, birds totally understand the Ackermann hierarchy arxiv.org/pdf/0905.4241

What are the most conceptually satisfying and/or generally accepted mathematical

What are the most conceptually satisfying and/or generally accepted mathematical explanations to date of the unreasonably good generalization properties of overparameterized models?

Permissionless Consensus Tutorial (13 of 13)

Speaker: Andrew Lewis-Pye (London School of Economics) Coauthor: Tim Roughgarden (Columbia University) Accompanying paper: https://arxiv.org/pdf/2304.14701 Accompanying tweetstorm: https://x.com/Tim_Roughgarden/status/1749600309750514139 Abstract: Blockchain protocols such as Bitcoin and Ethereum operate in the “permissionless” setting (as opposed to the “permissioned” setting, as classically studied in distributed computing). The shift from the permissioned to the permissionless setting entails three distinct challenges: * The unknown players challenge. The set of distinct entities that m

Permissionless Consensus Tutorial (12 of 13)

Speaker: Andrew Lewis-Pye (London School of Economics) Coauthor: Tim Roughgarden (Columbia University) Accompanying paper: https://arxiv.org/pdf/2304.14701 Accompanying tweetstorm: https://x.com/Tim_Roughgarden/status/1749600309750514139 Abstract: Blockchain protocols such as Bitcoin and Ethereum operate in the “permissionless” setting (as opposed to the “permissioned” setting, as classically studied in distributed computing). The shift from the permissioned to the permissionless setting entails three distinct challenges: * The unknown players challenge. The set of distinct entities that m

Permissionless Consensus Tutorial (11 of 13)

Speaker: Andrew Lewis-Pye (London School of Economics) Coauthor: Tim Roughgarden (Columbia University) Accompanying paper: https://arxiv.org/pdf/2304.14701 Accompanying tweetstorm: https://x.com/Tim_Roughgarden/status/1749600309750514139 Abstract: Blockchain protocols such as Bitcoin and Ethereum operate in the “permissionless” setting (as opposed to the “permissioned” setting, as classically studied in distributed computing). The shift from the permissioned to the permissionless setting entails three distinct challenges: * The unknown players challenge. The set of distinct entities that m

Permissionless Consensus Tutorial (10 of 13)

Speaker: Andrew Lewis-Pye (London School of Economics) Coauthor: Tim Roughgarden (Columbia University) Accompanying paper: https://arxiv.org/pdf/2304.14701 Accompanying tweetstorm: https://x.com/Tim_Roughgarden/status/1749600309750514139 Abstract: Blockchain protocols such as Bitcoin and Ethereum operate in the “permissionless” setting (as opposed to the “permissioned” setting, as classically studied in distributed computing). The shift from the permissioned to the permissionless setting entails three distinct challenges: * The unknown players challenge. The set of distinct entities that m

Permissionless Consensus Tutorial (9 of 13)

Speaker: Andrew Lewis-Pye (London School of Economics) Coauthor: Tim Roughgarden (Columbia University) Accompanying paper: https://arxiv.org/pdf/2304.14701 Accompanying tweetstorm: https://x.com/Tim_Roughgarden/status/1749600309750514139 Abstract: Blockchain protocols such as Bitcoin and Ethereum operate in the “permissionless” setting (as opposed to the “permissioned” setting, as classically studied in distributed computing). The shift from the permissioned to the permissionless setting entails three distinct challenges: * The unknown players challenge. The set of distinct entities that m

Permissionless Consensus Tutorial (8 of 13)

Speaker: Andrew Lewis-Pye (London School of Economics) Coauthor: Tim Roughgarden (Columbia University) Accompanying paper: https://arxiv.org/pdf/2304.14701 Accompanying tweetstorm: https://x.com/Tim_Roughgarden/status/1749600309750514139 Abstract: Blockchain protocols such as Bitcoin and Ethereum operate in the “permissionless” setting (as opposed to the “permissioned” setting, as classically studied in distributed computing). The shift from the permissioned to the permissionless setting entails three distinct challenges: * The unknown players challenge. The set of distinct entities that m

Permissionless Consensus Tutorial (7 of 13)

Speaker: Andrew Lewis-Pye (London School of Economics) Coauthor: Tim Roughgarden (Columbia University) Accompanying paper: https://arxiv.org/pdf/2304.14701 Accompanying tweetstorm: https://x.com/Tim_Roughgarden/status/1749600309750514139 Abstract: Blockchain protocols such as Bitcoin and Ethereum operate in the “permissionless” setting (as opposed to the “permissioned” setting, as classically studied in distributed computing). The shift from the permissioned to the permissionless setting entails three distinct challenges: * The unknown players challenge. The set of distinct entities that m

Permissionless Consensus Tutorial (6 of 13)

Speaker: Andrew Lewis-Pye (London School of Economics) Coauthor: Tim Roughgarden (Columbia University) Accompanying paper: https://arxiv.org/pdf/2304.14701 Accompanying tweetstorm: https://x.com/Tim_Roughgarden/status/1749600309750514139 Abstract: Blockchain protocols such as Bitcoin and Ethereum operate in the “permissionless” setting (as opposed to the “permissioned” setting, as classically studied in distributed computing). The shift from the permissioned to the permissionless setting entails three distinct challenges: * The unknown players challenge. The set of distinct entities that m

Permissionless Consensus Tutorial (5 of 13)

Speaker: Andrew Lewis-Pye (London School of Economics) Coauthor: Tim Roughgarden (Columbia University) Accompanying paper: https://arxiv.org/pdf/2304.14701 Accompanying tweetstorm: https://x.com/Tim_Roughgarden/status/1749600309750514139 Abstract: Blockchain protocols such as Bitcoin and Ethereum operate in the “permissionless” setting (as opposed to the “permissioned” setting, as classically studied in distributed computing). The shift from the permissioned to the permissionless setting entails three distinct challenges: * The unknown players challenge. The set of distinct entities that m

Permissionless Consensus Tutorial (4 of 13)

Speaker: Andrew Lewis-Pye (London School of Economics) Coauthor: Tim Roughgarden (Columbia University) Accompanying paper: https://arxiv.org/pdf/2304.14701 Accompanying tweetstorm: https://x.com/Tim_Roughgarden/status/1749600309750514139 Abstract: Blockchain protocols such as Bitcoin and Ethereum operate in the “permissionless” setting (as opposed to the “permissioned” setting, as classically studied in distributed computing). The shift from the permissioned to the permissionless setting entails three distinct challenges: * The unknown players challenge. The set of distinct entities that m

Permissionless Consensus Tutorial (3 of 13)

Speaker: Andrew Lewis-Pye (London School of Economics) Coauthor: Tim Roughgarden (Columbia University) Accompanying paper: https://arxiv.org/pdf/2304.14701 Accompanying tweetstorm: https://x.com/Tim_Roughgarden/status/1749600309750514139 Abstract: Blockchain protocols such as Bitcoin and Ethereum operate in the “permissionless” setting (as opposed to the “permissioned” setting, as classically studied in distributed computing). The shift from the permissioned to the permissionless setting entails three distinct challenges: * The unknown players challenge. The set of distinct entities that m

Permissionless Consensus Tutorial (2 of 13)

Speaker: Andrew Lewis-Pye (London School of Economics) Coauthor: Tim Roughgarden (Columbia University) Accompanying paper: https://arxiv.org/pdf/2304.14701 Accompanying tweetstorm: https://x.com/Tim_Roughgarden/status/1749600309750514139 Abstract: Blockchain protocols such as Bitcoin and Ethereum operate in the “permissionless” setting (as opposed to the “permissioned” setting, as classically studied in distributed computing). The shift from the permissioned to the permissionless setting entails three distinct challenges: * The unknown players challenge. The set of distinct entities that m