A relay device intended to set up a communication between a source device and a destination device through a circuit comprising at least one relay comprising the relay device and belonging to a computer network comprising at least one shared memory, the relay device comprising a processor configured to implement a communications capability receiving, from the source device or from a preceding relay within the circuit, a request for generating a proof of use, called a PoU frame, and a computing resource configured to compute a signature from a challenge and from a key proper to the relay device, the communications capability sending, to the destination device, or from a next relay within the circuit in the direction of the destination device, the PoU frame in adding thereto at least the computed signature and a value of the challenge used by each of the at least one relay to compute the signatures, the communications capability subsequently receiving, from the source device or from the destination device, at least one transaction frame comprising at least the signatures of the at least one relay contained in the PoU frame, the communications capability sending, subsequently to the reception of the at least one transaction, a request for recording, in a shared memory, a proof of use of the relay device comprising at least the signatures of each of the at least one relay of the circuit.