Abstract:
We propose new provable practical deterministic polynomial time algorithm of cryptographic analysis
for the braid Wang, Xu, Li, Lin and Wang «Double shielded public key cryptosystems», where the authors
recommended the Artin braid groups Bn as platforms for proposed protocols. We show that a linear
decomposition attack based on the decomposition method introduced by the author works for the image
of braids under the Lawrence-Krammer representation by finding the exchanging keys in the both two
main protocols by Wang et. al. These keys can be effectively computed in their original form too.
Thus the protocols propоsed by Wang et. al. are vulnerable.
