EA044749B1 - QUANTUM COMMUNICATION DEVICE AT THE SIDE FREQUENCIES WITH AN INCREASED DEGREE OF INFORMATION SECURITY FROM EXTERNAL ATTACKS - Google Patents

Description

Field and State of the Art

The invention relates to optical communication technology, namely to photonic quantum communication systems.

A device for quantum distribution of symmetric bit sequences is known [US patent 627 22 24 B1, priority date 04/07/2001. MKI: H04L 9/08; NO4K 1/00], containing a sender unit connected via a fiber-optic communication line, including a monochromatic radiation source located sequentially along the direction of radiation propagation, an electro-optical phase modulator and an attenuator, as well as a phase shift device, the output of which is connected to the control input of the electro-optical phase modulator, and the input of the phase shift device is connected to the output of the radio frequency signal generator, and the receiver block, which includes an electro-optical phase modulator, the output of which is optically coupled to a spectral filter, which is optically coupled to a classical radiation receiver and a single photon detector, the control input of the electro-optical phase modulator connected to the output of the phase shift device, to the input of which the output of the radio frequency signal generator is connected, the fiber-optic communication line is optically coupled to the attenuator of the transmitting device and to the input of the electro-optical phase modulator of the receiving device, the device contains a synchronization unit, the first and second outputs of which are connected to the inputs of the generator radio frequency signal of the receiving and transmitting devices, respectively, as well as a phase shift control unit, the first and second outputs of which are connected to the synchronizing inputs of the phase shift device of the receiving and transmitting devices, respectively.

The disadvantage of this device is the lack of protection in the technical implementation from external attacks, such as: attacks with blinding of a single-photon detector, attacks with interception of re-emission signals of single-photon detectors, attacks with optical probing of modulators (Trojan horse). In practice, photonic quantum communication systems must be resistant to external attacks.

Disclosure of the invention

The technical task of the proposed photonic quantum communication device is to change the technical implementation of the photonic quantum communication device, increasing the degree of information security from external attacks, such as: attacks with blinding of a single-photon detector, attacks with interception of re-emission signals of single-photon detectors, attacks with optical sensing of modulators (Trojan horse ).

The technical result of the proposed device consists in a new technical implementation of the sender and receiver blocks of a photonic quantum communication device, which protects the device from external attacks listed above.

The technical result of increasing the degree of information security from external attacks, such as: attacks with blinding of a single-photon detector, attacks with interception of re-emission signals of single-photon detectors, attacks with optical probing of modulators (Trojan horse) is achieved by introducing into the sender and receiver blocks: passive fiber optical attenuator, two fiber optical isolators, temperature controller, optical fiber beam splitter, fiber optical spectral filter, fiber optical circulator, fiber optical switch, three fiber photodetectors.

Brief description of drawings

The figure is a schematic diagram of a photonic quantum communication system according to an embodiment of the present invention.

Carrying out the invention

The design of the photonic quantum communication system is presented in the figure, where 1 is a source of monochromatic radiation in the form of a laser, 2 is a fiber optical isolator, 3 is an electro-optical phase modulator, 4 is a tunable fiber optical attenuator, 5 is a passive fiber optical attenuator, 6 is a fiber optical isolator , 7 - temperature controller, 8 - quantum channel for transmitting single photons, 9 - fiber optical isolator, 10 - fiber optical beam splitter (50/50) having two ports, 11, 20 and 21 - photodetectors with different optical sensitivities, 12 and 18 - fiber spectral filters, 13 - fiber polarizing beam splitter having two ports, 16 - fiber polarizing connector having two ports, 14 and 15 - electro-optical phase modulators, 17 - fiber optical circulator having three ports (indicating port numbers), 19 - fiber optical switch or fiber optical beam splitter, 22 - single-photon photodetector, 23 - radio-electronic control and synchronization unit of the sender unit, 24 - channel for transmitting a classic synchronization signal from the radio-electronic unit of the transmitter to the radio-electronic unit of the receiver (synchronization channel), 25 - open channel communication for classical communication between radio-electronic units of the sender and recipient, 26 - radio-electronic control and synchronization unit of the recipient unit.

The tunable fiber optical attenuator 4 in this embodiment is designed to attenuate radiation to the level specified by the protocol per phase modulation cycle

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Claims (1)

total at side frequencies. Let's consider the features of the principles of operation of the sender and recipient blocks depending on various external attacks. The principle of operation of a device protected from attack by imposing triggering of a single-photon detector: single-photon radiation carrying information necessary for the transfer of quantum information in the form of quantum states from the sender block of the photonic quantum communication system, passing through the quantum channel, enters the recipient block of the photonic quantum communication system . In the receiver block, the radiation hits the fiber spectral filter 12, which cuts off the entire spectral range of wavelengths not involved in the transmission of quantum information, then the radiation passes through the first port of the fiber optical circulator 17 and hits the second fiber spectral filter 18, reflecting a narrow spectral range, in which contains single-photon radiation carrying information necessary for the transmission of quantum information and, in some implementations of photonic quantum communication systems, also auxiliary radiation that does not contain information about the quantum states of single photons; the radiation reflected from the fiber spectral filter passes through the second port of the fiber optical circulator and falls on the single photon detector 22. The radiation passed through the second fiber spectral filter 18 falls on the fiber optical switch or fiber optical beam splitter 19, which directs it to two photodetectors with different optical sensitivities 20, 21, for constant monitoring of the optical power of the radiation, passed through the first fiber spectral filter 12. An attempt to impose triggers on the single photon detector will be reflected in the power of the auxiliary radiation, which does not contain information about the quantum states of single photons. Constant monitoring of the optical power of the auxiliary radiation passing through the fiber spectral filter makes it possible to detect an attempt to force triggering of the single photon detector. The use of a fiber optic switch and two photodetectors with different sensitivities will allow control of a wide range of optical powers. The principle of operation of a photonic quantum communication device with protection against attacks against attacks with interception of re-emission signals of a single-photon detector: to prevent the registration of re-emission signals of a single-photon detector, a fiber-optic circulator 17 and an optical fiber isolator 9 are installed at the input of the recipient block of the photonic quantum communication system, which prevents the passage of optical radiation back to the quantum channel. The principle of operation of a device for transmitting quantum states with protection from optical probing of modulators: to prevent the interception of reflected radiation from the modulators of the sender and receiver blocks of the photonic quantum communication device, a passive optical attenuator 5 and a fiber optical isolator 6 are placed in the sender block, preventing the passage of optical radiation from the quantum communication channel to the sender block. Also, the passive optical attenuator 5 and the fiber optical isolator 6 are equipped with a temperature control 7, which makes it possible to detect an attempt to damage optical components with high optical power. A fiber beam splitter 10 and a fiber photodetector 11 are placed in the receiver block between the optical isolator 9 and the fiber spectral filter 12, allowing for constant monitoring of the optical power going back to the quantum channel from the receiver block. CLAIM 1. A quantum communication device at side frequencies, with an increased degree of information security from external attacks, containing a sender block, which contains a source of monochromatic radiation (1), a first fiber optical isolator (2) connected to a source of monochromatic radiation (1), a first electro-optical phase modulator (3) connected to the first fiber optical isolator (2), tunable fiber optical attenuator (4) connected to the first electro-optical phase modulator (3), passive fiber optical attenuator (5) connected to the tunable fiber optical attenuator (4 ), a second optical isolator (6) connected to a passive fiber optical attenuator (5), a temperature controller (7) connected to a passive fiber optical attenuator (5) and a second optical isolator (6), and an electronic control and synchronization unit (23 ), connected to the first electro-optical phase modulator (3), and a receiver unit, which contains a third optical isolator (9), a fiber optical beam splitter (10) connected to the third optical isolator (9), a first fiber photodetector (11) connected to fiber optical beam splitter (10), first spectral filter (12) connected to the fiber optical beam splitter (10), fiber polarization beam splitter (13) connected to the first spectral filter (12), second and third electro-optical phase modulators (14, 15) , connected to the fiber polarization beam splitter (13), fiber polarization connector (16) connected to the second and third electroop -