Polynomial-time solutions of computational problems in noncommutative-algebraic cryptography

Abstract

We introduce the \emph{linear centralizer method}, and use it to devise a provable polynomial time solution of the Commutator Key Exchange Problem, the computational problem on which, in the passive adversary model, the security of the Anshel--Anshel--Goldfeld 1999 \emph{Commutator} key exchange protocol is based. We also apply this method to the computational problem underlying the \emph{Centralizer} key exchange protocol, introduced by Shpilrain and Ushakov in 2006. This is the first provable polynomial time cryptanalysis of the Commutator key exchange protocol, hitherto the most important key exchange protocol in the realm of noncommutative-algebraic cryptography, and the first cryptanalysis (of any kind) of the Centralizer key exchange protocol. Unlike earlier cryptanalyses of the Commutator key exchange protocol, our cryptanalyses cannot be foiled by changing the distributions used in the protocol.

Minor changes. Now published

References in corpus (5)

• Braid Groups are Linear
• Probabilistic Solutions of Equations in the Braid Group
• Length-Based Attacks for Certain Group Based Encryption Rewriting Systems
• Braid Group Cryptography
• A family of pseudo-Anosov braids with large conjugacy invariant sets

Cited by in corpus (5)

• A Practical Cryptanalysis of the Algebraic Eraser
• Cryptanalysis of Andrecut's public key cryptosystem
• Post-Quantum Cryptography: A Zero-Knowledge Authentication Protocol
• Cryptanalysis of two schemes of Baba et al. by linear algebra methods
• Complete simultaneous conjugacy invariants in Artin's braid groups