Computing Optimal Manipulations in Cryptographic Self-Selection Proof-of-Stake Protocols

Fuente: arXiv
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Main Authors: Ferreira, Matheus V. X., Ganesh, Aadityan, Hourigan, Jack, Huh, Hannah, Weinberg, S. Matthew, Yu, Catherine
Format: Preprint
Published: 2024
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author Ferreira, Matheus V. X.
Ganesh, Aadityan
Hourigan, Jack
Huh, Hannah
Weinberg, S. Matthew
Yu, Catherine
author_facet Ferreira, Matheus V. X.
Ganesh, Aadityan
Hourigan, Jack
Huh, Hannah
Weinberg, S. Matthew
Yu, Catherine
contents Cryptographic Self-Selection is a paradigm employed by modern Proof-of-Stake consensus protocols to select a block-proposing "leader." Algorand [Chen and Micali, 2019] proposes a canonical protocol, and Ferreira et al. [2022] establish bounds $f(α,β)$ on the maximum fraction of rounds a strategic player can lead as a function of their stake $α$ and a network connectivity parameter $β$. While both their lower and upper bounds are non-trivial, there is a substantial gap between them (for example, they establish $f(10\%,1) \in [10.08\%, 21.12\%]$), leaving open the question of how significant of a concern these manipulations are. We develop computational methods to provably nail $f(α,β)$ for any desired $(α,β)$ up to arbitrary precision, and implement our method on a wide range of parameters (for example, we confirm $f(10\%,1) \in [10.08\%, 10.15\%]$). Methodologically, estimating $f(α,β)$ can be phrased as estimating to high precision the value of a Markov Decision Process whose states are countably-long lists of real numbers. Our methodological contributions involve (a) reformulating the question instead as computing to high precision the expected value of a distribution that is a fixed-point of a non-linear sampling operator, and (b) provably bounding the error induced by various truncations and sampling estimations of this distribution (which appears intractable to solve in closed form). One technical challenge, for example, is that natural sampling-based estimates of the mean of our target distribution are \emph{not} unbiased estimators, and therefore our methods necessarily go beyond claiming sufficiently-many samples to be close to the mean.
format Preprint
id arxiv_https___arxiv_org_abs_2406_15282
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Computing Optimal Manipulations in Cryptographic Self-Selection Proof-of-Stake Protocols
Ferreira, Matheus V. X.
Ganesh, Aadityan
Hourigan, Jack
Huh, Hannah
Weinberg, S. Matthew
Yu, Catherine
Computer Science and Game Theory
Cryptography and Security
Theoretical Economics
G.3
Cryptographic Self-Selection is a paradigm employed by modern Proof-of-Stake consensus protocols to select a block-proposing "leader." Algorand [Chen and Micali, 2019] proposes a canonical protocol, and Ferreira et al. [2022] establish bounds $f(α,β)$ on the maximum fraction of rounds a strategic player can lead as a function of their stake $α$ and a network connectivity parameter $β$. While both their lower and upper bounds are non-trivial, there is a substantial gap between them (for example, they establish $f(10\%,1) \in [10.08\%, 21.12\%]$), leaving open the question of how significant of a concern these manipulations are. We develop computational methods to provably nail $f(α,β)$ for any desired $(α,β)$ up to arbitrary precision, and implement our method on a wide range of parameters (for example, we confirm $f(10\%,1) \in [10.08\%, 10.15\%]$). Methodologically, estimating $f(α,β)$ can be phrased as estimating to high precision the value of a Markov Decision Process whose states are countably-long lists of real numbers. Our methodological contributions involve (a) reformulating the question instead as computing to high precision the expected value of a distribution that is a fixed-point of a non-linear sampling operator, and (b) provably bounding the error induced by various truncations and sampling estimations of this distribution (which appears intractable to solve in closed form). One technical challenge, for example, is that natural sampling-based estimates of the mean of our target distribution are \emph{not} unbiased estimators, and therefore our methods necessarily go beyond claiming sufficiently-many samples to be close to the mean.
title Computing Optimal Manipulations in Cryptographic Self-Selection Proof-of-Stake Protocols
topic Computer Science and Game Theory
Cryptography and Security
Theoretical Economics
G.3
url https://arxiv.org/abs/2406.15282