A Practical Attack on a Braid Group Based Cryptographic Protocol

In this paper we present a practical heuristic attack on the Ko, Lee et al. key exchange protocol introduced at Crypto 2000 [10]. One of the ideas behind our attack is using Dehornoy’s handle reduction method as a counter measure to diffusion provided by the Garside normal form, and as a tool for simplifying braid words. Another idea employed in our attack is solving the decomposition problem in a braid group rather than the conjugacy search problem.

• Type: Conference
• Year: 2005
• Where: CRYPTO
• Authors: Alexei G. Myasnikov, Vladimir Shpilrain, Alexander Ushakov
• Keywords: CRYPTO 2005, Dehornoy’s Handle Reduction, Garside Normal Form, Practical Heuristic Attack