A method for evaluating a function of a finite field of characteristic p into itself, for an element x of the field, uses an evaluation, for the element x, of a polynomial formed by a plurality of monomials. The secure communication connection may be created even when the user computer communicates with a web server computer that does not support secure communication connections. A common rotating actuator controls the opening angle of both the main throttle valve and the auxiliary throttle valve through an actuating mechanism. This causes a voice call having the first and the second connection legs to be initially established between the mobile device and the destination device via the gateway.