Abstract: Method for computing a logical AND between two chosen bits, xi, xj, held by first and second participants, including a first phase comprising a step in which said first and second participants determine a first correlation variable and a second correlation variable, each determine a random bit, p and q, and transmit, to said server, a value dependent on said random bit p, q, a step in which the server prepares a photon in a first state; a step in which said first participant applies a first transformation V Up to said photon; a step in which the second participant applies a second transformation V Uq to said photon, and a step in which the server performs a third transformation (U*)p+q, measures the state of the photon and determines a third correlation variable; and a second phase comprising a step in which said first and second participants exchange a value u1, u2 dependent on the sum of the random bit, p, q and the chosen bit, xi, xj; and a step in which said first participant computes and delivers a first

Abstract: The present application relates to a method for securely transmitting a sequence of quantum states between a first participant Ci and a second participant Cj among a plurality of N participants, and to a device implementing said secure transmission method.

Abstract: The present invention is related to a method for delegation by a client of the creation of an unknown quantum state to a quantum server, the client having a simplified architecture based on a beam splitter, and the delegation method comprising in particular steps of activating an interaction through the beam splitter and masking by means of delays.

Abstract: The invention relates to a processing device (1) comprising: —an input interface (2) receiving photons having first quantum states, —an encoder (3) generating a photon having a first fixed quantum state from a received electrical signal, —a transformer (4) transforming the first quantum state of a photon into a second quantum state, —a decoder (5) transforming the second quantum state of a photon into an electrical signal, —an output interface (6) delivering photons which have second quantum states and are intended for transmission, —and a switch (7) comprising three inputs connected respectively to the outputs of the input interface (2), encoder (3) and transformer (4), and three outputs connected respectively to the inputs of the output interface (6), decoder (5) and transformer (4), said switch selectively coupling at least one of its inputs to one of its outputs, depending on a received command.