  We find a self-dual noncommutative and noncocommutative Hopf algebra acting
as a universal symmetry on the modules over inner Frobenius algebras of modular
categories (as used in two dimensional boundary conformal field theory) similar
to the Grothendieck-Teichmueller group GT as introduced by Drinfeld as a
universal symmetry of quasitriangular quasi-Hopf algebras. We discuss the
relationship to a similar self-dual, noncommutative, and noncocommutative Hopf
algebra, previously found as the universal symmetry of trialgebras and three
dimensional extended topological quantum field theories. As an application of
our result, we get a transitive action of a sub-Hopf algebra of the latter
universal symmetry algebra on the relative period matrices of holomorphic N=1
special geometries.
