  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.
