Computation of centralizers in braid groups and Garside groups. (English) Zbl 1064.20040

The authors give a new method to compute the centralizer of an element in Artin braid groups and, more generally, in Garside groups. This method, together with the solution of the conjugacy problem given previously by the authors, are two main steps for solving conjugacy systems, thus breaking recently discovered cryptosystems based in braid groups. They also present the result of their computations, where they notice that their algorithm yields surprisingly small generating sets for the centralizers.


20F36 Braid groups; Artin groups
20F10 Word problems, other decision problems, connections with logic and automata (group-theoretic aspects)
94A60 Cryptography
20F05 Generators, relations, and presentations of groups
68W30 Symbolic computation and algebraic computation
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