Abstract: The present invention relates to an Entropy measurement method comprising the steps of a start-up phase comprising powering on the entropy source unity, a signal emitting step comprising emitting a quantum signal characterized by an overall noise made of classical noise and quantum noise, a noise measurement step comprising measuring the statistics of overall noise through active pixels upon illumination and the statistics of classical noise through non-illuminated pixels, a quantum noise calculation step comprising calculating the quantum noise based on the difference between the overall noise and the classical noise, an health check step comprising comparing the resulting quantum noise to an expected quantum noise and/or a predetermined threshold and a health control step controlling the entropy source unit based on the result of the entropy estimation step.

Abstract: Some embodiments provide methods and apparatus for quantum random number generation based on a single bit or multi bit Quanta Image Sensor (QIS) providing single-photon counting over a time interval for each of an array of pixels of the QIS, wherein random number data is generated based on the number of photons counted over the time interval for each of the pixels.

Abstract: A receiver for recognizes blinding attacks in a quantum encrypted channel having an optical fiber. The receiver includes a multipixel detector having a plurality of pixels, and configured to be illuminated by a light beam outputted by the optical fiber. A processing unit connects to the multipixel detector and is configured to determine the presence of a blinding attack if a predetermined number of pixels detects light within a predetermined interval. The receiver recognizes blinding attacks in a quantum encrypted channel and implements a method for recognizing blinding attacks in a quantum encrypted channel.

Abstract: Some embodiments provide methods and apparatus for quantum random number generation based on a single bit or multi bit Quanta Image Sensor (QIS) providing single-photon counting over a time interval for each of an array of pixels of the QIS, wherein random number data is generated based on the number of photons counted over the time interval for each of the pixels.

Abstract: A photon detection device having a high light detection efficiency. The photon detection device includes a first light reception part which receives a gate signal and outputs a first signal; a second light reception part which receives a gate signal and outputs a second signal; and a determination part which determines whether or not a photon is received, on the basis of the first signal from the first light reception part and the second signal from the second light reception part. The photon is incident on the first light reception part among the first light reception part and the second light reception part, and the breakdown voltage of the second light reception part is higher than the breakdown voltage of the first light reception part.

Abstract: The present invention relates to a lidar (1000) comprising an emitter (1100) and a receiver (1200), wherein the receiver (1200) comprises a discrete amplification photon detector (1210), wherein the receiver (1200) comprises a discriminator (1220), wherein the discriminator (1220) has an input connected to an output signal of the discrete amplification photon detector (1210), and wherein the discriminator (1220) is configured to output a signal indicating that the output signal of the discrete amplification photon detector (1210) is higher than a predetermined threshold.

Abstract: The present invention relates to a receiver (2200) for recognizing blinding attacks in a quantum encrypted channel (1300) comprising an optical fiber, comprising a multipixel detector (2210) comprising a plurality of pixels, and configured to be illuminated by a light beam outputted by the optical fiber, and a processing unit (2220) connected to the multipixel detector (2210) and configured to determine the presence of a blinding attack if a predetermined number of pixels detects light within a predetermined interval. The invention further relates to the use of the receiver (2200) for recognizing blinding attacks in a quantum encrypted channel (1300) and to a method for recognizing blinding attacks in a quantum encrypted channel (1300).

Abstract: The present invention relates to a receiver (2200) for recognizing blinding attacks in a quantum encrypted channel (1300) comprising an optical fiber, comprising a multipixel detector (2210) comprising a plurality of pixels, and configured to be illuminated by a light beam outputted by the optical fiber, and a processing unit (2220) connected to the multipixel detector (2210) and configured to determine the presence of a blinding attack if a predetermined number of pixels detects light within a predetermined interval. The invention further relates to the use of the receiver (2200) for recognizing blinding attacks in a quantum encrypted channel (1300) and to a method for recognizing blinding attacks in a quantum encrypted channel (1300).

Abstract: The present relates to a quantum communication system for free space quantum key distribution. An emitter and a receiver, the emitter and the receiver are two points distanced by a free space quantum communication channel, the emitter being designed for wirelessly transmitting data to the receiver via said free space optical communication channel. The receiver includes an optical device capable of receiving the data within a predetermined field of view extending from said optical device toward the receiver. The system is characterized in that the emitter further comprises a light protecting device attached on said emitter. The light protecting device is configured to prevent any light coming from the environment beyond the emitter to enter within the field of view of the receiver. The invention further relates to a method for optimizing free space quantum key distribution.

Abstract: Free-Space key distribution method comprising exchanging information between an emitter (100) and a receiver (200) based on the physical layer wiretap channel model, comprising the steps of randomly preparing (710), at the emitter (100), one qubit encoded with one of two possible non-identical quantum states, sending (720) the encoded qubit to the receiver (200) through a physical layer quantum-enhanced wiretap channel (500), such that an eavesdropper (300) tapping said channel is provided with partial information about the said states only, detecting and measuring (730) the received quantum states, key sifting (740) between the emitter and the receiver through a classical channel, calculating (750, 760) an amount of information available to any eavesdropper (300) based on the detected and received quantum states.

Abstract: Some embodiments provide methods and apparatus for quantum random number generation based on a single bit or multi bit Quanta Image Sensor (QIS) providing single-photon counting over a time interval for each of an array of pixels of the QIS, wherein random number data is generated based on the number of photons counted over the time interval for each of the pixels.

Abstract: A quantum key distribution (QKD) system comprising: an emitter (110) adapted to generate a QKD free-space signal, a transmitter station (220) adapted to receive the free-space signal from the emitter (110), and a remote QKD receiving station (250) supporting a QKD receiver (160) located at a different location than the transmitter station, wherein the transmitter station is adapted to receive said free space signal from the emitter and to forward said signal through a fiber link (400) to the QKD receiver (160) in said remote QKD receiving station (250).

Abstract: The present invention relates to a measuring device (3000) for measuring reflection in an optical fiber (1400), the device comprising: emitting means (3100) connected to the optical fiber (1400) and configured to emit light into the optical fiber (1400), measuring means (3300) connected to the optical fiber (1400) and configured to receive a reflected light from the optical fiber (1400), wherein the measuring means comprises a first photon detector (3310) and a second photon detector (3311), wherein the operation of the second photon detector (3311) and/or the reflected light reaching the second photon detector (3311) is controlled based on an output of the first photon detector (3310).

Abstract: The present disclosure in some embodiments provides a method and an apparatus for providing a quantum cryptographic key distribution stabilization, which can quickly and efficiently compensate for an error caused by a temperature change, a change in polarization of a transmission path of an optical system included in a quantum cryptographic key distribution system in a cost-effective manner working perfectly with the very conventional quantum cryptographic key distribution system.

Abstract: An apparatus for enhancing secret key rate exchange over quantum channel in QKD systems includes an emitter system with a quantum emitter and a receiver system with a quantum receiver, wherein both systems are connected by a quantum channel and a service communication channel. User interfaces within the systems allow to define a first quantum channel loss budget based on the distance to be covered between the quantum emitter and the quantum receiver and the infrastructure properties of the quantum channel as well as a second quantum channel loss budget associated to the loss within the realm of the emitter system. The emitter system is adapted to define the optimal mean number of photons of coherent states to be emitted based on the first and the second quantum channel loss budgets.

Abstract: The present relates to a quantum communication system for free space quantum key distribution. An emitter and a receiver, the emitter and the receiver are two points distanced by a free space quantum communication channel, the emitter being designed for wirelessly transmitting data to the receiver via said free space optical communication channel. The receiver includes an optical device capable of receiving the data within a predetermined field of view extending from said optical device toward the receiver. The system is characterized in that the emitter further comprises a light protecting device attached on said emitter. The light protecting device is configured to prevent any light coming from the environment beyond the emitter to enter within the field of view of the receiver. The invention further relates to a method for optimizing free space quantum key distribution.

Abstract: The invention relates to a IM bias voltage determining method adapted to determine an IM bias voltage corresponding to a desired Quantum Bit Error Rate based on the following formula Q ? ( V IM ) = Q 0 + R err R err + R cor where Q(VIM) is the QBER dependent of the IM bias voltage VIM, Q0 is the optimal minimal QBER, Rerr is the number of erroneous detections, Rcor is the number of correct detections and VIM is the IM bias voltage.

Abstract: The invention relates to a QKD System Active combiner (200) adapted to be installed in a QKD apparatus, said QKD apparatus comprising an emitter (100), a receiver (110) and QKD systems (102/112), wherein the emitter (100) is adapted to send communication signals to the receiver (110) through the QKD System Active combiner (200), characterized in that the QKD System Active combiner (200) comprises an active attenuation system comprising a processing unit (230) adapted to automatically control at least one variable optical attenuator (150) through a control channel (290) in order to control an attenuation of a signal to be sent to the receiver, and a detector/monitor (240) adapted to monitor the intensity of the signal downstream the attenuation, and wherein the processing unit is adapted to control the variable optical attenuator (150) based on a QBER information or an intensity of a signal received by the receiver, sent by the QKD systems (112) through a classical channel (250).

Abstract: The present invention relates to a receiver (2200) for recognizing blinding attacks in a quantum encrypted channel (1300) comprising an optical fiber, comprising a multipixel detector (2210) comprising a plurality of pixels, and configured to be illuminated by a light beam outputted by the optical fiber, and a processing unit (2220) connected to the multipixel detector (2210) and configured to determine the presence of a blinding attack if a predetermined number of pixels detects light within a predetermined interval. The invention further relates to the use of the receiver (2200) for recognizing blinding attacks in a quantum encrypted channel (1300) and to a method for recognizing blinding attacks in a quantum encrypted channel (1300).

Abstract: The present disclosure discloses a random number generating apparatus capable of equalizing the spatial intensity distribution of light signals that are radiated from a light resource and are input to individual pixels.