  The three-dimensional topological insulator \ce{Bi2Te3} differs from other
topological insulators in the \ce{Bi2Se3} family in that the effective
Hamiltonian of its surface states on a flat semi-infinite slab requires the
addition of a cubic momentum hexagonal warping term in order to reproduce the
experimentally measured constant energy contours. In this work, we derive the
appropriate effective Hamiltonian for the surface states of a \ce{Bi2Te3}
\textit{cylinder} incorporating the corresponding hexagonal warping terms in a
cylindrical geometry. We show that at the energy range where the surface states
dominate, the effective Hamiltonian adequately reproduces the dispersion
relation obtained from a full four-band Hamiltonian, which describe both the
bulk and surface states. As an example application of our effective
Hamiltonian, we study the transmission between two collinear \ce{Bi2Te3}
cylinders magnetized in different directions perpendicular to their axes. We
show that the hexagonal warping term results in a transmission profile between
the cylinders which may be of utility in a multiple state magnetic memory bit.
