Non-malleable reductions and applications

Divesh Aggarwal, Yevgeniy Dodis, Tomasz Kazana, Maciej Obremski

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


Non-malleable codes, introduced by Dziembowski, Pietrzak and Wichs [DPW10], provide a useful message integrity guarantee in situations where traditional error-correction (and even error-detection) is impossible; for example, when the attacker can completely overwrite the encoded message. Informally, a code is non-malleable if the message contained in a modified codeword is either the original message, or a completely "unrelated value". Although such codes do not exist if the family of "tampering functions" F allowed to modify the original codeword is completely unrestricted, they are known to exist for many broad tampering families F. The family which received the most attention [DPW10, LL12, DKO13, ADL14, CG14a, CG14b] is the family of tampering functions in the so called (2-part) split-state model: here the message x is encoded into two shares L and R, and the attacker is allowed to arbitrarily tamper with each L and R individually. Despite this attention, the following problem remained open: Build efficient, information-theoretically secure non-malleable codes in the split-state model with constant encoding rate: |L| = |R| = O(|x|). In this work, we resolve this open problem. Our technique for getting our main result is of independent interest. We (a) develop a generalization of non-malleable codes, called non-malleable reductions; (b) show simple composition theorem for non-malleable reductions; (c) build a variety of such reductions connecting various (independently interesting) tampering families F to each other; (d) construct several new non-malleable codes in the split-state model by applying the composition theorem to a series of easy to understand reductions. Most importantly, we show several "independence amplification" reductions, showing how to reduce split-state tampering of very few parts to an easier question of split-state tampering with a much larger number of parts. In particular, our final, constant-rate, non-malleable code composes one of these reductions with the very recent, "9-split-state" code of Chattopadhyay and Zuckerman [CZ14].

Original languageEnglish (US)
Title of host publicationSTOC 2015 - Proceedings of the 2015 ACM Symposium on Theory of Computing
PublisherAssociation for Computing Machinery
Number of pages10
ISBN (Electronic)9781450335362
StatePublished - Jun 14 2015
Event47th Annual ACM Symposium on Theory of Computing, STOC 2015 - Portland, United States
Duration: Jun 14 2015Jun 17 2015

Publication series

NameProceedings of the Annual ACM Symposium on Theory of Computing
ISSN (Print)0737-8017


Other47th Annual ACM Symposium on Theory of Computing, STOC 2015
Country/TerritoryUnited States

ASJC Scopus subject areas

  • Software


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