Agile cryptography: A universally composable approach

Christian Badertscher*, Michele Ciampi, Aggelos Kiayias

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract / Description of output

Being capable of updating cryptographic algorithms is an inevitable and essential practice in cryptographic engineering. This cryptographic agility, as it has been called, is a fundamental desideratum for long term cryptographic system security that still poses significant challenges from a modeling perspective. For instance, current formulations of agility fail to express the fundamental security that is expected to stem from timely implementation updates, namely the fact that the system retains some of its security properties provided that the update is performed prior to the deprecated implementation becoming exploited. In this work we put forth a novel framework for expressing updateability in the context of cryptographic primitives within the universal composition model. Our updatable ideal functionality framework provides a general template for expressing the security we expect from cryptographic agility capturing in a fine grained manner all the properties that can be retained across implementation updates. We exemplify our framework over two basic cryptographic primitives, digital signatures and non-interactive zero-knowledge (NIZK), where we demonstrate how to achieve updateability with consistency and backwards-compatibility across updates in a composable manner. We also illustrate how our notion is a continuation of a much broader scope of the concept of agility introduced by Acar, Belenkiy, Bellare, and Cash in Eurocrypt 2010 in the context of symmetric cryptographic primitives.
Original languageEnglish
Title of host publicationTheory of Cryptography
Subtitle of host publication21st International Conference
EditorsGuy Rothblum, Hoeteck Wee
PublisherSpringer
Pages480-509
Number of pages30
Volume14372
Edition1
ISBN (Electronic)9783031486159
ISBN (Print)9783031486142
DOIs
Publication statusPublished - 27 Nov 2023
Event21st International conference on Theory of Cryptography Conference - Taipei, Taiwan, Province of China
Duration: 29 Nov 20232 Dec 2023
https://tcc.iacr.org/2023

Publication series

NameLecture Notes in Computer Science
PublisherSpringer
Volume14372
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference21st International conference on Theory of Cryptography Conference
Abbreviated titleTCC 2023
Country/TerritoryTaiwan, Province of China
CityTaipei
Period29/11/232/12/23
Internet address

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