Universal Reductions: Reductions Relative to Stateful Oracles

Benjamin Chan, Cody Freitag, Rafael Pass

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


We define a framework for analyzing the security of cryptographic protocols that makes minimal assumptions about what a “realistic model of computation is”. In particular, whereas classical models assume that the attacker is a (perhaps non-uniform) probabilistic polynomial-time algorithm, and more recent definitional approaches also consider quantum polynomial-time algorithms, we consider an approach that is more agnostic to what computational model is physically realizable. Our notion of universal reductions models attackers as PPT algorithms having access to some arbitrary unbounded stateful Nature that cannot be rewound or restarted when queried multiple times. We also consider a more relaxed notion of universal reductions w.r.t. time-evolving, k-window, Natures that makes restrictions on Nature—roughly speaking, Nature’s behavior may depend on number of messages it has received and the content of the last k(λ) -messages (but not on “older” messages). We present both impossibility results and general feasibility results for our notions, indicating to what extent the extended Church-Turing hypotheses are needed for a well-founded theory of Cryptography.

Original languageEnglish
Title of host publicationTheory of Cryptography - 20th International Conference, TCC 2022, Proceedings
EditorsEike Kiltz, Vinod Vaikuntanathan
PublisherSpringer Science and Business Media Deutschland GmbH
Number of pages30
ISBN (Print)9783031223679
StatePublished - 2022
Event20th Theory of Cryptography Conference, TCC 2022 - Chicago, United States
Duration: 7 Nov 202210 Nov 2022

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume13749 LNCS


Conference20th Theory of Cryptography Conference, TCC 2022
Country/TerritoryUnited States

All Science Journal Classification (ASJC) codes

  • Theoretical Computer Science
  • General Computer Science


Dive into the research topics of 'Universal Reductions: Reductions Relative to Stateful Oracles'. Together they form a unique fingerprint.

Cite this