Cliptography: Clipping the power of kleptographic attacks

Alexander Russell, Qiang Tang, Moti Yung, Hong Sheng Zhou

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

34 Scopus citations

Abstract

Kleptography, introduced 20 years ago by Young and Yung [Crypto ’96], considers the (in)security of malicious implementations (or instantiations) of standard cryptographic primitives that may embed a “backdoor” into the system. Remarkably, crippling subliminal attacks are possible even if the subverted cryptosystem produces output indistinguishable from a truly secure “reference implementation.” Bellare, Paterson, and Rogaway [Crypto ’14] recently initiated a formal study of such attacks on symmetric key encryption algorithms, demonstrating that kleptographic attacks can be mounted in broad generality against randomized components of cryptographic systems. We enlarge the scope of current work on the problem by permitting adversarial subversion of (randomized) key generation; in particular, we initiate the study of cryptography in the complete subversion model, where all relevant cryptographic primitives are subject to kleptographic attacks.We construct secure one-way permutations and trapdoor one-way permutations in this “complete subversion” model, describing a general, rigorous immunization strategy to clip the power of kleptographic subversions. Our strategy can be viewed as a formal treatment of the folklore “nothing up my sleeve” wisdom in cryptographic practice. We also describe a related “split program” model that can directly inform practical deployment. We additionally apply our general immunization strategy to directly yield a backdoor-free PRG. This notably amplifies previous results of Dodis, Ganesh, Golovnev, Juels, and Ristenpart [Eurocrypt ’15], which require an honestly generated random key. We then examine two standard applications of (trapdoor) one-way permutations in this complete subversion model and construct “higher level” primitives via black-box reductions. We showcase a digital signature scheme that preserves existential unforgeability when all algorithms (including key generation, which was not considered to be under attack before) are subject to kleptographic attacks. Additionally, we demonstrate that the classic Blum–Micali pseudorandom generator (PRG), using an “immunized” one-way permutation, yields a backdoor-free PRG. Alongside development of these secure primitives, we set down a hierarchy of kleptographic attack models which we use to organize past results and our new contributions; this taxonomy may be valuable for future work.

Original languageEnglish (US)
Title of host publicationAdvances in Cryptology - ASIACRYPT 2016 - 22nd International Conference on the Theory and Application of Cryptology and Information Security, Proceedings
EditorsJung Hee Cheon, Tsuyoshi Takagi
PublisherSpringer Verlag
Pages34-64
Number of pages31
ISBN (Print)9783662538890
DOIs
StatePublished - 2016
Event22nd International Conference on the Theory and Application of Cryptology and Information Security, ASIACRYPT 2016 - Hanoi, Viet Nam
Duration: Dec 4 2016Dec 8 2016

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume10032 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Other

Other22nd International Conference on the Theory and Application of Cryptology and Information Security, ASIACRYPT 2016
Country/TerritoryViet Nam
CityHanoi
Period12/4/1612/8/16

All Science Journal Classification (ASJC) codes

  • Theoretical Computer Science
  • Computer Science(all)

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