2026-09-18T19:00:09Zhttps://ecommons.cornell.edu/server/oai/requestoai:ecommons.cornell.edu:1813/1211302026-05-15T17:53:58Zcom_1813_35col_1813_47
Chan, Benjamin
Pass, Rafael
Shi, Runting
Juels, Ari
Stephens-Davidowitz, Noah
2026-04-03T18:53:59Z
2026-04-03T18:53:59Z
2025-12
ProQuest Submission ID: 15291
ProQuest Publication ID: 32244437
https://hdl.handle.net/1813/121130
https://doi.org/10.7298/eqh4-5m80
17423376
264 pages
This is a thesis in two parts. First, we re-visit the foundations of consensus protocols, arguing that despite 50 years of research, there is room to make them simpler, more secure, and more efficient. As a pillar of distributed systems, consensus algorithms power everything from distributed databases to decentralized infrastructure. The protocols covered in this thesis (Streamlet (Chan and Shi, 2020), Simplex (Chan and Pass, 2023), and variants) are the simplest in the literature, and are now taught in universities and power an increasing number of projects in industry. Second, we re-examine the fundamental meaning of what it means for a protocol to be cryptographically secure -- the basis of Modern Cryptography. Classical "provable security" assumes that the attacker is probabilistic polynomial-time in nature (or perhaps quantum) and stateless. In contrast, our notion of Universal Reductions (Chan, Freitag, and Pass, 2022)) models attackers as arbitrary unbounded stateful algorithms -- agnostic to what computational model is physically realizable by the universe, yielding a more general (and future-proof) notion of security.
en
Attribution-NoDerivatives 4.0 International
https://creativecommons.org/licenses/by-nd/4.0/
consensus
cryptography
distributed algorithms
security
theory of computation
CRYPTOGRAPHY FROM CONSENSUS TO THE COSMOS
dissertation or thesis
application/pdf
Computer Science
Cornell University
Doctor of Philosophy
Ph. D., Computer Science
https://hdl.handle.net/1813/59810.2
Publication
Cornell Theses and Dissertations
Chan, Benjamin
5893a6ea-7af3-41d7-abc6-04bcd26ab5df
open.access
open.access
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<Abstract>This is a thesis in two parts. First, we re-visit the foundations of consensus protocols, arguing that despite 50 years of research, there is room to make them simpler, more secure, and more efficient. As a pillar of distributed systems, consensus algorithms power everything from distributed databases to decentralized infrastructure. The protocols covered in this thesis (Streamlet (Chan and Shi, 2020), Simplex (Chan and Pass, 2023), and variants) are the simplest in the literature, and are now taught in universities and power an increasing number of projects in industry. Second, we re-examine the fundamental meaning of what it means for a protocol to be cryptographically secure -- the basis of Modern Cryptography. Classical "provable security" assumes that the attacker is probabilistic polynomial-time in nature (or perhaps quantum) and stateless. In contrast, our notion of Universal Reductions (Chan, Freitag, and Pass, 2022)) models attackers as arbitrary unbounded stateful algorithms -- agnostic to what computational model is physically realizable by the universe, yielding a more general (and future-proof) notion of security.</Abstract>
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