Cube Testers and Key Recovery Attacks On Reduced-Round MD6 and Trivium

Jean Philippe Aumasson, Itai Dinur, Willi Meier, Adi Shamir

Research output: Contribution to journalConference articlepeer-review

3 Scopus citations


CRYPTO 2008 saw the introduction of the hash function MD6 and of cube attacks, a type of algebraic attack applicable to cryptographic functions having a low-degree algebraic normal form over GF(2). This paper applies cube attacks to reduced round MD6, finding the full 128-bit key of a 14-round MD6 with complexity 222 (which takes less than a minute on a single PC). This is the best key recovery attack announced so far for MD6. We then introduce a new class of attacks called cube testers, based on efficient property-testing algorithms, and apply them to MD6 and to the stream cipher Trivium. Unlike the standard cube attacks, cube testers detect nonrandom behavior rather than performing key extraction, but they can also attack cryptographic schemes described by nonrandom polynomials of relatively high degree. Applied to MD6, cube testers detect nonrandomness over 18 rounds in 217 complexity; applied to a slightly modified version of the MD6 compression function, they can distinguish 66 rounds from random in 224 complexity. Cube testers give distinguishers on Trivium reduced to 790 rounds from random with 230 complexity and detect nonrandomness over 885 rounds in 227, improving on the original 767-round cube attack.

Original languageEnglish
JournalDagstuhl Seminar Proceedings
StatePublished - 1 Jan 2009
Externally publishedYes
EventSymmetric Cryptography 2009 - Wadern, Germany
Duration: 11 Jan 200916 Jan 2009

ASJC Scopus subject areas

  • Software
  • Hardware and Architecture
  • Control and Systems Engineering


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