A polynomial time algorithm for the braid double shielded public key cryptosystems

Abstract

We propose new provable practical deterministic polynomial time algorithm for the braid Wang, Xu, Li, Lin and Wang Double shielded public key cryptosystems. We show that a linear decomposition attack based on the decomposition method introduced by the author in monography "Algebraic Cryptography" (2013) and some papers works for the image of braids under the Lawrence-Krammer representation by finding the exchanging keys in both two main protocols by the authors listed above.