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Hauptverfasser: Maleki, Homayoun, Sainz, Nekane, Legarda, Jon, Santos-Grueiro, Igor
Format: Preprint
Veröffentlicht: 2026
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Online-Zugang:https://arxiv.org/abs/2605.29651
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author Maleki, Homayoun
Sainz, Nekane
Legarda, Jon
Santos-Grueiro, Igor
author_facet Maleki, Homayoun
Sainz, Nekane
Legarda, Jon
Santos-Grueiro, Igor
contents Permissionless systems resist Sybil attacks by binding influence to scarce resources. We show that scarcity alone is insufficient: the structural properties of the resource determine whether influence can be concentrated at sublinear cost through identity replication, delegation, or pooling. We model this through the adversarial cost C(s,T): the minimum expenditure required to achieve influence proportional to s independent participation units over T windows. We prove that any resource satisfying divisibility, additivity of influence, temporal reusability, and identity transferability admits influence amortization: C(s,T)=o(sT), regardless of protocol design. This is an impossibility result: no protocol rule can enforce linear cost of influence concentration over a structurally parallelizable resource. We further prove that throughput-bounded, non-transferable, window-local resources enforce C(s,T)=Omega(sT): each additional unit of sustained influence incurs marginal cost Delta(s,T)=Omega(T), growing with the time horizon. The two resource classes are asymptotically separated. As a direct design consequence, any mechanism targeting linear cost of influence concentration must ground participation in a resource that violates at least one parallelizability property.
format Preprint
id arxiv_https___arxiv_org_abs_2605_29651
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Scarcity Is Not Enough: An Impossibility Result for Linear Sybil Cost Under Parallelizable Resources
Maleki, Homayoun
Sainz, Nekane
Legarda, Jon
Santos-Grueiro, Igor
Cryptography and Security
Permissionless systems resist Sybil attacks by binding influence to scarce resources. We show that scarcity alone is insufficient: the structural properties of the resource determine whether influence can be concentrated at sublinear cost through identity replication, delegation, or pooling. We model this through the adversarial cost C(s,T): the minimum expenditure required to achieve influence proportional to s independent participation units over T windows. We prove that any resource satisfying divisibility, additivity of influence, temporal reusability, and identity transferability admits influence amortization: C(s,T)=o(sT), regardless of protocol design. This is an impossibility result: no protocol rule can enforce linear cost of influence concentration over a structurally parallelizable resource. We further prove that throughput-bounded, non-transferable, window-local resources enforce C(s,T)=Omega(sT): each additional unit of sustained influence incurs marginal cost Delta(s,T)=Omega(T), growing with the time horizon. The two resource classes are asymptotically separated. As a direct design consequence, any mechanism targeting linear cost of influence concentration must ground participation in a resource that violates at least one parallelizability property.
title Scarcity Is Not Enough: An Impossibility Result for Linear Sybil Cost Under Parallelizable Resources
topic Cryptography and Security
url https://arxiv.org/abs/2605.29651