  We introduce a relativistic version of quantum encryption protocol by
considering two inertial observers who wish to securely transmit quantum
information encoded in a free scalar quantum field state forming Minkowski
particles. In a non-relativistic setting a certain amount of shared classical
resources is necessary to perfectly encrypt the state. We show that in the case
of a uniformly accelerated eavesdropper the communicating parties need to share
(asymptotically in the limit of infinite acceleration) just half of the
classical resources.
