DEVICE FOR QUANTUM RANDOM NUMBER GENERATION AND METHOD FOR VERIFYING THE PRIVACY OF A SEQUENCE OF RANDOM NUMBER GENERATED THEREBY - Patent application

Abstract

The invention relates to a device for the quantum generation of random numbers, the device comprising a light source (100) with a fixed polarization, a polarization splitter element (110) optically connected to the light source (100), the polarization splitter element (110) having a first output (111) corresponding to vertical polarization and a second output (112) corresponding to horizontal polarization, a first detector (131) optically connected to the first output (111) of the polarization splitter element (110), a second detector (132) optically connected to the second output (112) of the polarization splitter element (110), a first input (141) connected to the output of the first detector (131), a second input (142) connected to the output of the second detector (132), and a second input (143) connected to the output of the first detector (131). and a generating module (140) having a second input (142) arranged to generate on the two-state output (143) a bit having a value of 1 when receiving a signal at the first input (141) and a bit having a value of 0 when receiving a signal at the second input (142), characterized in that the light source (100) is connected to the polarization splitting element (110) via a multi-state polarization modulator (150) controlled by a digital or analog signal generated by a control electronics (160) connected to the multi-state polarization modulator (150). The invention also comprises a method for verification of the privacy of a random bit sequence generated by such a device.

Description

[Technical field]

[0001] The present invention relates to an optical polarization-based device for quantum random number generation and a method for verification of the privacy of a random number sequence generated by the device for quantum random number generation. The generation of the random number sequence is performed by measuring a coherent quantum state or a Fock quantum state by a pair of single photon detectors. Recording the measurement results makes it possible to obtain a truly random bit sequence, which can be converted, if necessary, into a set of truly random numbers in decimal notation. The verification of privacy is performed by a multi-state polarization modulator or a pair of two-state polarization modulators that are part of the generator that modify the measured quantum state. [Background technology]

[0002] Random number generation is widely used in such technical fields as classical and quantum cryptography, computer numerical simulation (Monte Carlo method), and is also the basis for the operation of online casinos and lotteries. Depending on the principle of operation, random number generators are divided into pseudorandom number generators, where a computer algorithm deterministically generates a sequence of numbers with near-random properties based on a short set of random numbers called seeds, and true random number generators, where random numbers are generated based on inherently random physical phenomena (e.g., radioactive decay [K. Park, S. Park, BG Choi, T. Kang, J. Kim, Y.-H. Kim, H.-Z. Jin, “A lightweight true random number generator using beta radiation for loT applications”, ETRI Journal. 42(6), 951-964 (2020)] or electromagnetic atmospheric noise [https: / / www.random.orq / ]). Pseudorandom number generators have a number of drawbacks related to the periodic nature of the generated numbers and the unevenness of their distribution. Furthermore, if the seed is intercepted by an unauthorized person, that person can generate the same sequence of numbers without the knowledge of the generator's user, posing a significant threat to the privacy of the sequence.

[0003] Due to the probabilistic nature of measurements in quantum mechanics, the use of quantum phenomena to generate true random numbers has become a natural direction for the development of fast, cheap and miniaturized generators. The paper [X. Ma, X. Yuan, Z. Cao, B. Qi, Z. Zhang “Quantum random number generation” npj Quantum Information 2, 16021 (2016)] presents a review of the most important experiments carried out over the last 20 years in which quantum optical phenomena such as measurements of amplified spontaneous emission, measurements of quantum vacuum fluctuations, measurements of the quantum state of single photons, etc. are used to generate true random numbers. The perfect randomness of quantum random number generators and the privacy of the sequences generated by them derive from simplified theoretical models that assume ideal scenarios such as the user having sufficient knowledge of the structure of the device, the optical components having parameters that do not change over time, and no measurement errors occurring during the measurements. However, the operation of real generators always shows some deviations from the theoretical models, resulting, among other things, from temperature fluctuations, wear of optical and electronic components, and, in the worst case scenario, from deliberate interference by the manufacturer or other unauthorized parties in the device. Procedures need to be developed for testing (certification) of such devices to distinguish whether they generate predefined random number sequences known to the manufacturer or another unauthorized person, or whether they generate private sequences (i.e. sequences that cannot be guessed or reconstructed by unauthorized persons) generated in real time. Testing procedures are essential especially when a device is purchased from an external company and, as a result, the user does not have sufficient knowledge of its construction and must treat it as untrusted.

[0004] Quantum random number generators that test the privacy and randomness of the generated sequence during operation (self-testing generators) are the most secure class of devices with the widest range of applicability. This most secure class of devices is called the device-independent class of quantum random number generators. One of the first implementations of such a device is described in the paper [A. Kulikov, M. Jerger, A. Potocki, A. Wallraff, A. Fedorov “Realization of Quantum Random Generator Certified with the Kochen-Specker Theorem” Phys. Rev. Lett. 119, 240501 (2017)], where the test is performed using the Kochen-Specker theorem and the achieved random bit generation speed reaches 25 kbit / s.

[0005] The paper [D. Drahi et al. “Certified Quantum Random Numbers from Untrusted Light” Phys. Rev. X 10, 041048 (2020)] describes a record-breaking high-speed (8.05 Gbit / s) partially self-testing random number generator based on optical homodyne measurements of vacuum fluctuations. The generator consists of a continuous-wave laser, an adjustable optical attenuator, a beam splitter, a fast photodiode, and control electronics. A part of the light beam in the generator is used to test the input coherent state generated by the laser so that the generator can use untrusted light sources. The measurement system in the generator is not tested, so its implementation requires the use of a trusted photodetector. It is therefore a partially self-testing generator that belongs to a security class called the source-device independent class.

[0006] US20190393675 describes a random number generator in which an optical homodyne measurement is performed on an external light beam independently supplied to the device by the user. The phase of the local oscillator in the homodyne measurement can be fixed or random. This allows for example the measurement of different quadrature phases of the external light beam in a squeezed, coherent or vacuum state. By measuring the external state of light, this solution allows testing of the measurement system in the generator. However, a reliable light source, which is essential for the operation of the generator, needs to be independently purchased and tested by the user or independently built. It is therefore a partially self-testing generator that belongs to a security class called the measurement device independent class.

[0007] WO 2018 / 065593 describes two non-orthogonal states of light in a pair of time modes:

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number

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[0008] WO 2021 / 215941 presents a self-testing random number generator based on a set of multiport beam splitters, phase modulators and single photon detectors. One set of phase modulators is used to modify the state leaving the light source, while the other set of phase modulators is used to modify the state entering the multiport beam splitter-based detection system. Thanks to such a generator architecture, it is possible to independently test both the state of the light used to generate the randomness and the detector system. This arrangement is very difficult to implement in practice, since it requires maintaining phase stability between the multiple light beams interfering with each other in the multiport beam splitter. Further problems arise from the use of optical phase modulators, which require precise calibration of the operating point and control of environmental conditions such as temperature for stable operation.

[0009] Single-photon detectors based on superconductivity are known in the art [Eric A. Dauler et al., Review of superconducting nanowire single-photon detector system design options and demonstrated performance, Optical Engineering 53(8), 081907(2014)]. Such detectors are characterized by extremely low numbers of dark counts and very high quantum efficiency, allowing for effective detection of photons. Summary of the Invention [Problem to be solved by the invention]

[0010] A problem in the prior art is the design and construction of a quantum generator of truly random numbers, where the randomness is generated based on physical phenomena that are probabilistic in nature. The generated random number sequence is not known with absolute certainty to unauthorized parties, including the manufacturer of the generator, i.e., the generator guarantees the privacy of the sequence. Another problem in the prior art is the implementation of such a generator using the simplest possible optical system, consisting of commonly available and inexpensive optical and optoelectronic components.

[0011] Glossary and definitions of terms known in the art and used herein As used herein, the following terms have the following meanings, as set forth in the definitions below.

[0012] The term "random bits" refers to bits generated by a device that produces a truly random sequence of output bits.

[0013] The term "private bits" means bits generated by a device that cannot be guessed or reconstructed by any unauthorized party, including the manufacturer of the generator.

[0014] The term "control bit" refers to a bit of a digital signal that is applied to the electrical input of the polarization modulator(s).

[0015] The term "single-photon detector" refers to a device capable of detecting light having an energy corresponding to the energy of a single photon. Examples of such detectors include avalanche photodiodes, SPDs (single-photon detectors), and single-photon superconducting nanowire detectors, among others.

[0016] The term "polarization separation element," designated in the drawings at 110, refers to an optical element in which the vertical polarization of a light beam is transmitted and the horizontal polarization of a light beam is reflected. Examples of such elements are dielectrically coated polarizing beam splitting (PBS) cubes and birefringence-based polarizers (e.g., Wollaston prisms, Nicol prisms, Glan-Taylor prisms, Glan-Thompson prisms).

[0017] The term "self-testing generator" refers to a quantum random number generator that tests the privacy of the sequences it generates during its operation.

[0018] The term "click" refers to the generation of an electrical / electronic pulse in response to a recorded photon associated with a single-photon detector, or the spontaneous generation of an electrical / electronic pulse associated with dark counts.

[0019] The term "generation module" refers to an electronic circuit that generates a bit 0 when detector 131 records a count and a bit 1 when detector 132 generates a count. Module 140 is capable of generating a random bit sequence at a digital output 143. Such a module may be based on commonly available microcontrollers or field programmable gate arrays (FPGAs).

[0020] The term "vertically polarized" refers to the orientation of linearly polarized light such that a light beam having this polarization is transmitted through a polarization separation element.

[0021] The term "horizontally polarized" refers to the orientation of linearly polarized light such that a light beam having this polarization is reflected by a polarization separation element.

[0022] The term "oblique polarization" refers to the orientation of linear polarization when a light beam of this polarization is split equally into two light beams of equal energy by a polarization splitting element, such that the reflected beam is horizontally polarized and the transmitted beam is vertically polarized.

[0023] The term "privacy of the sequence" means that a bit sequence generated by a device cannot be inferred or reconstructed by unauthorized persons, including the manufacturer of the generator.

[0024] The term "unauthorized person" means any individual or organization that attempts to obtain information about a generated random sequence without the user's knowledge in an unauthorized manner and thus violates the privacy of the sequence. An unauthorized person can be a potential eavesdropper, the manufacturer of the device, a software provider, or other persons who are not the users of the device.

[0025] The term "control electronics" means an electrical system that generates digital or analog control signals to control a multi-state polarization modulator or a pair of two-state polarization modulators. Such a system can be based on a commonly available microcontroller or a field programmable gate array.

[0026] The term "privacy verification" means checking whether the maximum probability P g of an unauthorized person inferring a random bit is lower than the maximum allowable probability value X. Here, the range of X is from 50% to 100%. When the inequality P g < X is satisfied, the verification is positive. When the inequality P g < X is not satisfied, the verification is negative. In the case of the strategy of an unauthorized person inferring a random bit without additional information, the maximum probability P g is 50%. When the verification is positive, the device can generate random private bits.

[0027] The term "extinction coefficient" of a polarization separation element determines the ratio of the energy of a light beam transmitted by the element to the energy of the light beam reflected by the element when the beam incident on the element is vertically polarized. For example, a polarizing beam splitting (PBS) cube has an extinction coefficient of 1000:1.

[0028] The term "light source" refers to a coherent light source (e.g., a laser diode), a non-coherent light source (e.g., an LED diode), or a single-photon source (e.g., based on a single atom or quantum dot). The central wavelength of the light beam used in the device is in the range of 400-1600 nm. The average optical intensity of the light beam used in the device is less than 1 μW.

[0029] Other terms not defined above have the meaning given to them herein and understood by those of ordinary skill in the art in the context of their best knowledge, this disclosure, and the patent. [Means for solving the problem]

[0030] The invention described in this patent document comprises a novel design of a device and an innovative method of self-testing the generation of true random numbers based on the laws of quantum mechanics generated by this device. The device according to the invention includes in its structure one multi-state polarization modulator or a pair of two-state polarization modulators, providing the user of the device with the ability to verify the privacy of the generated random numbers. The unique design of the device makes it possible to detect possible interference by the device manufacturer and / or unauthorized persons in the process of generating true random numbers.

[0031] The invention relates to a device for the quantum generation of random numbers, said device comprising a light source 100 with a fixed polarization, a polarization splitter element 110 optically connected to the light source 100, said polarization splitter element 110 having a first output 111 corresponding to vertical polarization and a second output 112 corresponding to horizontal polarization, a first detector 131 optically connected to the first output 111 of the polarization splitter element 110, a second detector 132 optically connected to the second output 112 of the polarization splitter element 110, a first input 141 connected to the output of the first detector 131, and an output 142 connected to the output of the second detector 132. a generating module 140 having a first input 141 connected thereto, a second input 142 connected thereto, and a two-state output 143, the generating module 140 being configured to generate a bit on the two-state output 143 having a value of 1 when a signal is received at the first input 141 and a bit having a value of 0 when a signal is received at the second input 142, characterized in that the light source 100 is connected to the polarization splitting element 110 via a multi-state polarization modulator 150 controlled by a digital or analog signal generated by a control electronics 160 connected to the multi-state polarization modulator 150.

[0032] Preferably, the multi-state polarization modulator 150 comprises two two-state polarization modulators 251 and 252 optically connected to each other, both modulators configured to rotate the polarization by 45° when a control digital signal with a bit value of 1 is applied to their electrical input and to rotate the polarization by 0° when a control digital signal with a bit value of 0 is applied to their electrical input, or alternatively configured to rotate the polarization by 45° when a control digital signal with a bit value of 0 is applied to their electrical input and to rotate the polarization by 0° when a control digital signal with a bit value of 1 is applied to their electrical input.

[0033] Preferably, the multi-state polarization modulator 150 comprises two two-state polarization modulators 351 and 352 optically connected to each other, one of the modulators 351, 352 configured to rotate the polarization by 45° when a digital signal with a bit value of 1 is applied to its electrical input and to rotate the polarization by 0° when a digital signal with a bit value of 0 is applied to its electrical input, and the other of the modulators 351, 352 configured to rotate the polarization by 90° when a digital signal with a bit value of 1 is applied to its electrical input and to rotate the polarization by 0° when a digital signal with a bit value of 0 is applied to its electrical input, respectively.

[0034] Alternatively and preferably, the multi-state polarization modulator 150 comprises two two-state polarization modulators 351 and 352 optically connected to each other, one of the modulators 351, 352 configured to rotate the polarization by 45° when a digital signal with a bit value of 0 is applied to its electrical input and to rotate the polarization by 0° when a digital signal with a bit value of 1 is applied to its electrical input, and the other of the modulators 351, 352 configured to rotate the polarization by 90° when a digital signal with a bit value of 0 is applied to its electrical input and to rotate the polarization by 0° when a digital signal with a bit value of 1 is applied to its electrical input, respectively.

[0035] Preferably, the polarization separation element 110 is a polarizing beamsplitting cube with a dielectric coating, a birefringence-based polarizer, or a prism.

[0036] Preferably, light source 100 is a coherent light source, preferably comprising a laser diode or a pulsed laser, a non-coherent light source, preferably comprising an LED diode, or a single photon source, preferably based on a single atom or quantum dot.

[0037] Preferably, the light source 100 is configured to emit pulses of light that are vertically or horizontally polarized.

[0038] Preferably, the light source 100 is configured to generate a light beam having a central wavelength in the range of 400-1600 nm, the light beam having an average energy of less than 1 μW.

[0039] Preferably, both single-photon detectors 131 and 132 comprise avalanche photodiodes or superconducting-based single-photon detectors, or alternatively, one of detectors 131, 132 comprises an avalanche photodiode and the other detector comprises a superconducting-based single-photon detector.

[0040] Preferably, the optical path is an optical fiber, a waveguide, or a light beam in free space.

[0041] The invention also relates to a method for verification of the privacy of a random bit sequence generated by a device according to the invention, in which, when generating the random number, the polarization of the beam incident on the polarization splitter is oblique, i.e. rotated by 45°, with respect to the direction of polarization transmitted by the polarization splitter, and during the privacy verification, the control electronics 160 is used to control the multi-state polarization modulator 150 to rotate the polarization of the light incident on the polarization splitter 110 to be set in the order 0°, 45° and 90° with respect to the polarization direction transmitted by the polarization splitter, and for each of the three polarization directions (0°, 45°, 90°) a sequence of bits generated by the generation module 140 is recorded, after which, based on each of the three sequences, a probability P of recording a count by the first detector 131 is calculated. I and the probability P of recording a count by the second detector 132 II is determined and six probabilities are given, namely:

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[0042] Preferably, the maximum probability P of guessing a random bit by an unauthorized person is g A physical model is used to determine the following parameters: (a) The average number of photons in the measured pulse - μ, (b) Transmission coefficient - λ, (c) Probability f

[0043] Preferably, the verification of the privacy of the generated random bit string is considered positive depending on whether the determined parameter values ​​(μ0, λ0, f0) of the physical model belong to a predefined set of numerical values ​​in a three-dimensional space (μ, λ, f) calculated based on the physical model and on the maximum allowed value X of the probability of guessing the random bits by an unauthorized person.

[0044] Preferably, the maximum allowable probability X of guessing the random bits by an unauthorized person is in the range of 50% to 100%.

[0045] Preferably, the maximum allowable probability X of guessing random bits by an unauthorized person is 75%, and when X=75%, the determined parameter values ​​(μ0, λ0, f0) of the physical model are such that the following points in the three-dimensional space (μ, λ, f) (μ=0,λ=0,f=0), (μ=0,λ=0,75,f=0), (μ=10,λ=0,f=0), (μ=0,λ=0,f=1) The privacy verification of the generated random bit string is positive when it is inside a tetrahedron with a vertex in (i.e., P g <75%).

[0046] The invention also relates to a computer program, characterized in that it comprises instructions for implementing the method described above, when loaded into the control electronics 160 and into the generation module 140.

[0047] [Advantages of the invention] The invention according to this patent specification has a number of advantages: it allows the generation of truly random numbers while guaranteeing full confidence that the generated random number sequence will not be known to unauthorized parties, including the manufacturer of the generator; the use of the polarization degree of freedom makes its technical implementation much simpler than previously proposed solutions based on the interference and measurement of multiple light beams using an array of single photon detectors; [Brief description of the drawings]

[0048] Advantageous embodiments of the present invention The present invention will now be described in detail in embodiments with reference to the accompanying drawings, in which dotted lines connecting individual elements of the system indicate optical connections (e.g. optical fibers, waveguides, or light beams in free space) and solid lines connecting individual elements of the system indicate electrical connections, in which the following are disclosed:

[0049] [Figure 1]An embodiment of a device for quantum random number generation is shown. In this device, a multi-state modulator 150 is implemented as a pair of two-state polarization modulators 251, 252 controlled by control electronics 160. A light source 100 generates a coherent light beam with a fixed polarization that is either aligned or perpendicular to the direction of polarization transmitted by the polarization splitter element 110. The coherent light beam is then rotated by the pair of two-state polarization modulators 251, 252. The light beam enters the polarization splitter element 110, whose outputs 111, 112 are monitored by two single-photon detectors 131, 132. The single-photon detectors 131, 132 are electrically connected 141, 142 to the generation module 140. [Diagram 2] An embodiment of a device for quantum random number generation is shown. In this device, a multi-state modulator 150 is implemented as a pair of two-state polarization modulators 351, 352 controlled by control electronics 160. A light source 100 generates a coherent light beam with a fixed polarization that is either aligned or perpendicular to the direction of polarization transmitted by the polarization splitter element 110. The coherent light beam is then rotated by the pair of two-state polarization modulators 351, 352. The light beam enters the polarization splitter element 110, whose outputs 111, 112 are monitored by two single-photon detectors 131, 132. The single-photon detectors 131, 132 are electrically connected 141, 142 to the generation module 140. [Diagram 3] An embodiment of a device for quantum random number generation is shown. The device uses a multi-state modulator 150 controlled by control electronics 160. A light source 100 generates a coherent light beam with a fixed polarization that is either coincident with or perpendicular to the direction of polarization transmitted by the polarization splitter element 110. The coherent light beam is then rotated by the multi-state modulator 150. The light beam enters the polarization splitter element 110, whose outputs 111, 112 are monitored by two single-photon detectors 131, 132. The single-photon detectors 131, 132 are electrically connected 141, 142 to the generation module 140. [Figure 4]It shows a tetrahedron (in two different projections) in a three-dimensional Cartesian coordinate system, whose axes (μ, λ, f) represent parameter values ​​of a physical model. Inside the tetrahedron, the maximum probability Pg of guessing a random bit by an unauthorized person is less than 75%. Thus, the device enables the generation of private random bits.

[0050] The labels used in the drawings are consistent with the definitions in the glossary. Various types of optical and photonic connections are known in the prior art, e.g., optical fibers, waveguides, or light beams in free space, and are shown in the drawings as dotted lines. Solid lines in the figures indicate electrical connections, including hardwire connections and digital signal ports. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] The following embodiments of the invention are included solely for the purpose of illustrating the invention and describing certain aspects thereof, not for the purpose of limiting the invention, and should not be construed as the full scope of the invention as defined in the appended claims. In the following examples, unless otherwise noted, standard materials and methods used in the art are used, or manufacturer recommendations for particular devices, materials, and methods are followed.

[0052] Example 1 Device for quantum random number generation using a pair of two-state polarization modulators and method for verifying the privacy of a random number sequence generated by the device - Patents.com In the embodiment shown in FIG. 1 below, the light source 100 with a fixed polarization is a laser diode that emits a coherent light beam with vertical (alternatively horizontal) polarization. The polarization of the beam is then rotated by a multi-state polarization modulator 150 implemented as a pair of two-state polarization modulators, shown in FIG. 1 as 251, 252. Each of the polarization modulators 251, 252 is independently supplied with a digital control signal from the control electronics 160. Each modulator rotates the polarization of the light beam by 45° when a control bit value of 1 is applied to the electrical input of the modulator. On the other hand, each modulator rotates the polarization of the light beam by 0° when a control bit value of 0 is applied to the electrical input of the modulator. The operation of the first modulator 251 is independent of the operation of the second modulator 252. The light beam is then directed to a polarization separation element 110, preferably a polarizing beam splitting (PBS) cube, since they are widely available at low cost. Here, the vertically polarized light is transmitted and the horizontally polarized light is reflected. In case of oblique polarization (45° rotation), the polarizing beam splitting cube acts as a balanced beam splitting plate, i.e. it splits the incoming beam into two beams of equal energy. Each of the output beams of the polarizing beam splitting cubes 111, 112 is measured by a single photon detector 131, 132, preferably an avalanche photodiode or preferably a superconducting based single photon detector. Single photon detectors are characterized by extremely low dark counts and very high quantum efficiency, allowing effective photon detection.

[0053] The probability of a click at each of the detectors is

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[0054] To verify the privacy of the generated random number sequence, we use the click probability

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[0055] Based on the determined values of the above parameters (μ0, λ0, f0) of the physical model, the maximum probability P of guessing the random bit by an unauthorized person g is determined. The maximum probability P g is such that the inequality P g < X is satisfied, where X is the maximum allowable probability value for guessing the random bit by an unauthorized party and is in the range of 50% to 100%, but the device can generate random private bits. Preferably, the maximum probability P of guessing the random bit by an unauthorized person g should be less than 75%. The condition P g < 75% is satisfied when the point (μ0, λ0, f0) in the three-dimensional space (μ, λ, f) defined by the determined values of the parameters of the physical model is inside the tetrahedron shown in Figure 4, and its vertices are among the following points. (μ = 0, λ = 0, f = 0), (μ = 0, λ = 0, 75, f = 0), (μ = 10, λ = 0, f = 0), (μ = 0, λ = 0, f = 1)

[0056] For an unauthorized party strategy that relies on guessing random bits without additional information, the maximum probability P g is 50%.

[0057] Example 2 Alternative device for quantum random number generation using a pair of two-state polarization modulators and method for verifying the privacy of a random number sequence generated by the alternative device - Patents.com In the embodiment shown in Fig. 2 below, the light source 100 with fixed polarization is a laser diode emitting a coherent light beam with vertical (alternatively horizontal) polarization. The polarization of the beam is then rotated by a multi-state polarization modulator 150 implemented as a pair of two-state polarization modulators, shown in Fig. 1 as 351, 352. Each of the polarization modulators 351, 352 is independently supplied with a digital control signal from the control electronics 160. For the first modulator 351, a control bit value of 0 applied to the electrical input of the modulator rotates the polarization of the light beam by 0°, while a control bit value of 1 applied to the electrical input of the modulator rotates the polarization of the light beam by 45°. For the second modulator 352, a control bit value of 0 applied to the electrical input of the modulator rotates the polarization of the light beam by 0°, while a control bit value of 1 applied to the electrical input of the modulator rotates the polarization of the light beam by 90°. The operation of the first modulator 351 is independent of the operation of the second modulator 352. The order of the modulators 351 and 352 in the optical path does not affect the operation of the device. In this example, the modulator 351, which rotates the beam by 45°, is placed in the optical path closer to the light source 100 than the other modulator 352, which rotates the beam by 90°. The light beam is then directed to a polarization separation element 110, preferably a polarizing beam splitting (PBS) cube, since they are low cost and widely available. Here, vertically polarized light is transmitted and horizontally polarized light is reflected. For oblique polarizations (45° or 135° rotation), the polarizing beam splitting cube acts as a balanced beam splitting plate, i.e., it splits the incoming beam into two beams of equal energy. Each of the output beams of the polarizing beam splitting cubes 111, 112 is measured by a single-photon detector 131, 132, preferably an avalanche photodiode, or preferably a superconducting-based single-photon detector. Single photon detectors are characterized by extremely low dark counts and very high quantum efficiency, allowing for effective photon detection.

[0058] The probability of a click at each of the detectors is

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[0059] To verify the privacy of the generated random number sequence, we use the click probability

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[0060] Based on the determined values of the above parameters (μ0, λ0, f0) of the physical model, the maximum probability P of guessing the random bit by an unauthorized person g is determined. The maximum probability P g is such that the inequality P g < X is satisfied, where X is the maximum allowable probability value for guessing the random bit by an unauthorized person and is in the range from 50% to 100%, but the device can generate random private bits. Preferably, the maximum probability P of guessing the random bit by an unauthorized person g should be less than 75%. The condition P g < 75% is satisfied when the point (μ0, λ0, f0) in the three - dimensional space (μ, λ, f) defined by the determined values of the parameters of the physical model is inside the tetrahedron shown in FIG. 4, and its vertices are among the following points. (μ = 0, λ = 0, f = 0), (μ = 0, λ = 0, 75, f = 0), (μ = 10, λ = 0, f = 0), (μ = 0, λ = 0, f = 1)

[0061] For an unauthorized party strategy that relies on guessing random bits without additional information, the maximum probability P g is 50%.

[0062] Example 3 DEVICE FOR QUANTUM RANDOM NUMBER GENERATION USING A MULTI-STATE POLARIZATION MODULATOR AND METHOD FOR VERIFICATION OF THE PRIVACY OF A RANDOM NUMBER SEQUENCE GENERATED BY THE DEVICE - Patent application In the embodiment shown in Figure 3 below, a light source 100 with fixed polarization is a laser diode emitting a coherent light beam of vertical (alternatively horizontal) polarization. The polarization of the beam is then rotated by a single multi-state polarization modulator, shown as 150 in Figure 3. The modulator is supplied with an analog control signal from control electronics 160. A voltage V o When a voltage V1 is applied to the electrical input of the modulator, the polarization of the light beam is rotated by γ=45°, and when a voltage V2 is applied to the electrical input of the modulator, the polarization of the light beam is rotated by γ=25°. γ =90°. The light beam is then directed to a polarization separation element 110, preferably a polarizing beam splitting (PBS) cube, as it is widely available at low cost. Here, vertically polarized light is transmitted and horizontally polarized light is reflected. In the case of oblique polarization (45° rotation), the polarizing beam splitting cube acts as a balanced beam splitting plate, i.e., it splits the incoming beam into two beams of equal energy. Each of the output beams of the polarizing beam splitting cubes 111, 112 is measured by a single-photon detector 131, 132, preferably an avalanche photodiode, or preferably a superconducting-based single-photon detector. Single-photon detectors are characterized by extremely low dark counts and very high quantum efficiency, allowing for effective photon detection.

[0063] The probability of a click at each of the detectors is

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[0064] To verify the privacy of the generated random number sequence, we use the click probability

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[0065] Based on the determined values of the above parameters (μ0, λ0, f0) of the physical model, the maximum probability P of an unauthorized person guessing a random bit g is determined. The maximum probability P g is such that the inequality P g < X is satisfied, where X is the maximum allowable probability value for an unauthorized person to guess a random bit and is in the range of 50% to 100%. However, the device can generate random private bits. Preferably, the maximum probability P of an unauthorized person guessing a random bit g should be less than 75%. The condition P g < 75% is satisfied when the point (μ0, λ0, f0) in the three-dimensional space (μ, λ, f) defined by the determined values of the parameters of the physical model is inside the tetrahedron shown in FIG. 4, and its vertices are among the following points. (μ = 0, λ = 0, f = 0), (μ = 0, λ = 0, 75, f = 0), (μ = 10, λ = 0, f = 0), (μ = 0, λ = 0, f = 1)

[0066] In the case of a strategy of an unauthorized person that depends on guessing a random bit without additional information, the maximum probability P g is 50%.

[0067] [Applicable Fields of the Present Invention] The present invention can be used in technical fields such as IT and ICT cyber security, data encryption, and cryptography. Random number generators are widely used among users of computer and telephone networks. Furthermore, their use is particularly important in the encryption of sensitive data in the banking and financial sector, the power industry, industrial control and automation, protection of sensitive medical data, and communication in the military sector, government administration and secret intelligence agencies and diplomatic missions, where the sending and receiving of messages from remote facilities is subject to the risk of eavesdropping by unauthorized persons.

[0068] In addition, the present invention can be used in games of chance, especially number games, whose rules are based on true randomness of events and prevent parties from predicting the outcome of the draw. Random number generators are also used in numerical simulations that require true random sampling, for example Monte Carlo methods.

Claims

1. A device for the quantum generation of random numbers, said device comprising: a light source (100) with a fixed polarization; a polarization separation element (110) optically connected to said light source (100), said polarization separation element (110) having a first output (111) corresponding to vertical polarization and a second output (112) corresponding to horizontal polarization; a first detector (131) optically connected to the first output (111) of said polarization separation element (110); a second detector (132) optically connected to the second output (112) of said polarization separation element (110); a first input (141) connected to the output of the first detector (131), a second input (142) connected to the output of the second detector (132), a generating module (140) having a first input (141), a second input (142) connected to said first input (141), and a two-state output (143), said generating module (140) configured to generate a bit on said two-state output (143) having a value of 1 when receiving a signal at said first input (141) and a bit having a value of 0 when receiving a signal at said second input (142), characterized in that said light source (100) is connected to said polarization splitting element (110) via said multi-state polarization modulator (150) controlled by a digital or analog signal generated by control electronics (160) connected to said multi-state polarization modulator (150).

2. 2. The device of claim 1, wherein the multi-state polarization modulator (150) comprises two two-state polarization modulators (251) and (252) optically connected to each other, both of the two-state polarization modulators (251) and (252) being configured to rotate the polarization by 45° when a control digital signal with a bit value of 1 is applied to their electrical inputs and to rotate the polarization by 0° when a control digital signal with a bit value of 0 is applied to their electrical inputs, or alternatively to rotate the polarization by 45° when a control digital signal with a bit value of 0 is applied to their electrical inputs and to rotate the polarization by 0° when a control digital signal with a bit value of 1 is applied to their electrical inputs.

3. 2. The device of claim 1, wherein the multi-state polarization modulator (150) comprises two two-state polarization modulators (351) and (352) optically connected to each other, one of the two-state polarization modulators (351) and (352) configured to rotate the polarization by 45° when a digital signal with a bit value of 1 is applied to its electrical input and to rotate the polarization by 0° when a digital signal with a bit value of 0 is applied to its electrical input, and the other of the two-state polarization modulators (351) and (352) configured to rotate the polarization by 90° when a digital signal with a bit value of 1 is applied to its electrical input and to rotate the polarization by 0° when a digital signal with a bit value of 0 is applied to its electrical input, respectively.

4. 2. The device of claim 1, wherein the multi-state polarization modulator (150) comprises two two-state polarization modulators (351) and (352) optically connected to each other, one of the two-state polarization modulators (351) and (352) configured to rotate the polarization by 45° when a digital signal with a bit value of 0 is applied to its electrical input and to rotate the polarization by 0° when a digital signal with a bit value of 1 is applied to its electrical input, and the other of the two-state polarization modulators (351) and (352) configured to rotate the polarization by 90° when a digital signal with a bit value of 0 is applied to its electrical input and to rotate the polarization by 0° when a digital signal with a bit value of 1 is applied to its electrical input, respectively.

5. The device according to any one of claims 1 to 4, characterized in that the polarization separation element (110) is a polarizing beam splitting cube with a dielectric coating, a birefringence-based polarizer, or a prism.

6. The device according to any one of claims 1 to 5, characterized in that the light source (100) is a coherent light source, preferably comprising a laser diode or a pulsed laser, a non-coherent light source, preferably comprising an LED diode, or a single photon source, preferably based on a single atom or a quantum dot.

7. The device according to any one of claims 1 to 6, characterized in that the light source (100) is configured to emit light pulses with vertical or horizontal polarization or the light source (100) is configured to generate a light beam having a central wavelength in the range of 400 to 1600 nm, the average energy of the light beam being less than 1 μW.

8. The device according to any one of claims 1 to 7, characterized in that both single-photon detectors (131) and (132) comprise an avalanche photodiode or a superconducting-based single-photon detector, or alternatively, one of the single-photon detectors (131) and (132) comprises an avalanche photodiode and the other of the single-photon detectors (131) and (132) comprises a superconducting-based single-photon detector.

9. A device according to any one of claims 1 to 8, characterized in that the optical path is an optical fiber, a waveguide or a light beam in free space.

10. A method for verifying the privacy of a random bit sequence generated by a device according to any one of claims 1 to 9, comprising the steps of: generating a random number, the polarization of the beam incident on the polarization splitter is rotated obliquely, i.e. by 45°, with respect to the direction of polarization transmitted by said polarization splitter; during said privacy verification, using a control electronics (160), controlling a multi-state polarization modulator (150) to rotate the polarization of the light incident on the polarization splitter (110) to be set in the order of 0°, 45° and 90° with respect to the polarization direction transmitted by the polarization splitter; for each of the three polarization directions (0°, 45°, 90°), a bit sequence generated by the generation module (140) is recorded; and then, based on each of the three sequences, a probability P of recording a count by the first detector (131) is calculated. I and the probability P of recording a count by the second detector (132). II is determined and six probabilities are given: [0010] Based on Where: the superscripted Roman numerals I and II refer to the first detector (131) or the second detector (132), respectively; the subscripts xy, where x=0 or x=1 and y=0 or y=1, respectively denote the values ​​of the control bits applied to the first polarization modulator (251, 351) of the multi-state polarization modulator (150) and to the second polarization modulator (252, 352) of the multi-state polarization modulator (150); ・Subscript V 0 , V 1 , and V 2 respectively, the voltage V applied to the electrical input of the multi-state polarization modulator (150) 0 , V 1 , and V 2 where the parameters of a physical model of the system are calculated and the parameters are determined by the maximum probability P g is used to determine the maximum probability P g is lower than a maximum allowable probability value X of guessing random bits by an unauthorized person, the verification of privacy is considered positive.

11. The maximum probability P of guessing a random bit by an unauthorized person g A physical model is used to determine the parameters of (a) The average number of photons in the measured pulse - μ, (b) Transmission coefficient - λ, (c) probability f, The method according to claim 10, characterized in that

12. The verification of the privacy of the generated random bit string is performed by determining the parameter values ​​(μ 0 , λ 0 , f 0 12. The method according to claim 10 or 11, characterized in that the random bit is considered positive depending on whether the random bit belongs to a predefined set of numerical values ​​in a three-dimensional space (μ, λ, f) calculated on the basis of a physical model and on the maximum allowable value X of the probability of guessing a random bit by an unauthorized person.

13. 13. The method of claim 12, wherein said maximum allowable value X of the probability of guessing random bits by an unauthorized person ranges from 50% to 100%.

14. The maximum allowable probability X of guessing random bits by an unauthorized person is 75%, and if X=75%, the determined parameter value (μ 0 , λ 0 , f 0 ) is the following point in the three-dimensional space (μ, λ, f): (μ=0, λ=0, f=0), (μ=0,λ=0,75,f=0), (μ=10, λ=0, f=0), (μ=0, λ=0, f=1), When the vertex of the generated random bit string is inside a tetrahedron, the privacy verification of the generated random bit string is positive (i.e., P g 14. The method according to claim 13, characterized in that the concentration is < 75%.

15. A computer program, characterized in that it comprises instructions for implementing the method according to any one of claims 10 to 14, when it is loaded into a control electronics (160) and into a generation module (140).

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