Quantum random number generator

Abstract

The present disclosure provides a quantum random number generator, comprising: a light source component adapted to provide an initial optical signal; a detection component comprising a beam splitter and a balanced detector. The first input end of the beam splitter is closed so that the first input end receives a vacuum state signal, the second input end receives the initial optical signal, and outputs a first optical signal and a second optical signal; the balanced detector is adapted to convert the first optical signal and the second optical signal into a first electrical signal dependent on the first optical signal, a second electrical signal dependent on the second optical signal, and a third electrical signal dependent on the first electrical signal and the second electrical signal; the sampling and quantization component is adapted to output a first digital signal, a second digital signal, and a third digital signal; and the data processing component is adapted to obtain the optical wavelength of the initial optical signal, the intensity of the initial optical signal, and the beam splitting ratio of the beam splitter based on the first digital signal and the second digital signal, and to obtain a final random number based on the third digital signal.

Description

Technical Field

[0001] At least one embodiment of the present disclosure relates to the field of quantum secure communication technology, and more particularly to a quantum random number generator. Background Art

[0002] High-speed true random numbers are indispensable in cryptographic algorithms and are a critical foundational resource in the field of information security. Among various continuous-variable quantum random number generator (QRNG) schemes, those based on measuring vacuum fluctuation noise offer clear physical models, easy vacuum state preparation, high detection efficiency, and significant advantages in high-speed, real-time, and integrated applications. The reported random number generation rate of QRNGs based on measuring vacuum fluctuation noise has increased from 1 Mbps when the scheme was first proposed to 100 Gbps, further demonstrating the potential of QRNGs based on measuring vacuum fluctuation noise for ultra-high-speed true random number generation.

[0003] It's well known that the ability of a QRNG to generate provably secure random numbers is based on the intrinsic randomness of quantum physics processes. However, in practical implementations, the non-idealities of physical components make it impossible to guarantee that their operating conditions perfectly conform to theoretical models. An eavesdropper (Eve) could exploit these non-idealities to eavesdrop on or even control the system, threatening its actual security. For example, in a QRNG system based on vacuum fluctuation noise, extracting vacuum fluctuation noise using a balanced homodyne detector requires a strong local oscillator (LO) beam as a factor to amplify the weak vacuum signal. In theoretical security analysis models, the LO beam has a constant intensity and a single frequency. In practical systems, however, the LO beam is generated by a laser, and its intensity is dependent on the laser's drive current and inevitably fluctuates. Furthermore, the laser's output optical signal is not a perfectly single-frequency source and has a certain linewidth. In this case, the actual operating state of the LO beam is inconsistent with the theoretical model's requirements. If the QRNG system built using this laser does not quantitatively evaluate the intensity, frequency and other characteristic parameters of its local oscillator light and characterize the extractable randomness of the actual system, then the random numbers it generates will pose a security risk. That is, an eavesdropper may disguise himself as the supplier to pre-manufacture or manipulate the laser to eavesdrop on or control the random numbers output by the QRNG system, posing a serious threat to the security of the system.

[0004] In the related technologies for quantitatively evaluating the impact of changes (or fluctuations) in the intensity of local oscillator light on the security of quantum communication systems, most of them use additional optical beam splitters and detectors to split the local oscillator light at a small ratio and then monitor it to defend against possible potential attacks. However, they do not take into account the security issues caused by changes in the intensity and wavelength of the local oscillator light and the changes in the beam splitter ratio caused by the wavelength change, resulting in hidden dangers in the actual security of the QRNG system based on vacuum fluctuation noise. Summary of the Invention

[0005] To address at least one of the aforementioned and other technical problems in the prior art, the present disclosure provides a quantum random number generator that can obtain in real time the change in the wavelength of the local oscillator light and the change in the beam splitting ratio of the beam splitter in the balanced detector caused by the wavelength change, and can evaluate the extractable randomness of the quantum random number generator system in real time, thereby improving the actual security of the quantum random number generator system.

[0006] According to one aspect of the present disclosure, there is provided a quantum random number generator, comprising:

[0007] A light source assembly, adapted to provide an initial light signal;

[0008] Detection components, including:

[0009] A beam splitter, the beam splitter comprising a first input end and a second input end, the first input end being closed so as to receive a vacuum state signal generated by quantum fluctuations in a vacuum state; the second input end receiving the initial optical signal; the beam splitter being adapted to combine the vacuum state signal with the initial optical signal and output a first optical signal and a second optical signal comprising the vacuum state signal and the initial optical signal; and

[0010] a balanced detector adapted to convert the first optical signal and the second optical signal into a first electrical signal dependent on the first optical signal, a second electrical signal dependent on the second optical signal, and a third electrical signal dependent on the first electrical signal and the second electrical signal;

[0011] a sampling and quantization component adapted to convert the first electrical signal, the second electrical signal, and the third electrical signal into a first digital signal, a second digital signal, and a third digital signal, respectively; and

[0012] The data processing component is adapted to obtain the optical wavelength of the initial optical signal, the intensity of the initial optical signal and the splitting ratio of the beam splitter according to the first digital signal and the second digital signal, and to obtain a final random number according to the third digital signal.

[0013] According to an embodiment of the present disclosure, the conditional minimum entropy is obtained based on the optical wavelength of the above-mentioned initial optical signal, the intensity of the above-mentioned initial optical signal, the splitting ratio of the above-mentioned beam splitter and the above-mentioned third digital signal, and then the lower bound of the extractable randomness of the above-mentioned quantum random number generator is obtained.

[0014] According to an embodiment of the present disclosure, the above-mentioned balanced detector includes:

[0015] a first photodiode, adapted to obtain a fourth electrical signal based on the first optical signal;

[0016] a first splitter, adapted to divide the fourth electrical signal into a first electrical signal and a first sub-electrical signal in proportion;

[0017] a second photodiode, adapted to obtain a fifth electrical signal based on the second optical signal;

[0018] a second splitter, adapted to divide the fifth electrical signal into a second electrical signal and a second sub-electrical signal in proportion; and

[0019] The subtractor is adapted to perform difference processing on the first sub-signal and the second sub-signal to output a third electrical signal.

[0020] According to an embodiment of the present disclosure, the ratio of the intensity of the first electrical signal to the intensity of the first sub-electrical signal satisfies The ratio of the intensity of the second electrical signal to the intensity of the second sub-electrical signal satisfies .

[0021] According to an embodiment of the present disclosure, the sampling and quantization component includes:

[0022] a first converter, adapted to convert the first electrical signal into a first digital signal;

[0023] a second converter adapted to convert the second electrical signal into a second digital signal; and

[0024] a third converter, adapted to convert the third electrical signal into a third digital signal;

[0025] The first converter, the second converter and the third converter are all capable of amplifying the first electrical signal, the second electrical signal and the third electrical signal.

[0026] According to an embodiment of the present disclosure, the detection component further includes an adjustable attenuator, which is adapted to control the intensity of the first optical signal and the second optical signal so that the intensity of the fourth electrical signal is the same as that of the fifth electrical signal.

[0027] According to an embodiment of the present disclosure, a transmission coefficient of the beam splitter is obtained according to the first digital signal and the second digital signal. The transmission coefficient of the beam splitter can be expressed as formula (1):

[0028] (1),

[0029] in, represents the transmission coefficient of the above beam splitter; represents the average value of the first digital signal; represents the average value of the second digital signal; represents the detection efficiency difference coefficient between the first photodiode and the second photodiode; is the ratio of the overall conversion gain coefficient of the fourth electrical signal after passing through the first shunt and the first converter to the overall conversion gain coefficient of the fifth electrical signal after passing through the second shunt and the second converter; is the wavelength of the initial optical signal.

[0030] According to an embodiment of the present disclosure, the average optical power of the initial optical signal satisfies formula (2):

[0031] (2),

[0032] in, represents the average optical power of the initial optical signal; , is the detection efficiency of the first photodiode; is the detection efficiency of the second photodiode; is the overall conversion gain coefficient of the fourth electrical signal after passing through the first shunt and the first converter; is the detection efficiency difference coefficient between the first photodiode and the second photodiode.

[0033] According to an embodiment of the present disclosure, the beam splitting ratio of the above beam splitter satisfies formula (3):

[0034] (3),

[0035] in, represents the splitting ratio of the above beam splitter; represents the transmission coefficient of the above beam splitter.

[0036] According to an embodiment of the present disclosure, the above-mentioned beam splitter is a 2×2 beam splitter, and the above-mentioned 2×2 beam splitter also includes a first output end and a second output end. The above-mentioned first optical signal output by the above-mentioned first output end is input into the above-mentioned first photodiode; the above-mentioned second optical signal output by the above-mentioned second output end is input into the above-mentioned second photodiode.

[0037] According to an embodiment of the present disclosure, an initial light signal is provided by setting a light source component, and a detection component including a beam splitter and a balanced detector is provided, wherein the beam splitter includes a first input end and a second input end, the first input end is closed so that the first input end receives a vacuum state signal with quantum fluctuations; the second input end receives the initial light signal; the beam splitter is adapted to output a first light signal and a second light signal including the vacuum state signal and the initial light signal after merging the vacuum state signal with the initial light signal, and utilizes a balanced detector to convert the first light signal and the second light signal into a first electrical signal dependent on the first light signal, a second electrical signal dependent on the second light signal, and a third electrical signal dependent on the first electrical signal and the second light signal. The invention relates to a method for generating a quantum random number generator system using a plurality of optical signals, wherein the first optical signal, the second optical signal and the third optical signal are converted into a first digital signal, a second digital signal and a third digital signal respectively by using a sampling and quantization component; the optical wavelength of the initial optical signal, the intensity of the initial optical signal and the splitting ratio of the beam splitter are obtained according to the first digital signal and the second digital signal by using a data processing component, and the final random number is obtained according to the third digital signal. The method can obtain in real time the changes in the intensity and wavelength of the local oscillator light used to provide the initial optical signal and the changes in the splitting ratio of the beam splitter caused by the wavelength change, and can evaluate in real time the extractable randomness of the quantum random number generator system, thereby improving the actual security of the quantum random number generator system. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above contents and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0039] Figure 1 Schematically shows a block diagram of a quantum random number generator according to an embodiment of the present disclosure;

[0040] Figure 2 The figure schematically shows the working principle of the quantum random number generator according to an embodiment of the present disclosure.

[0041] In the above drawings, the meanings of the reference numerals are as follows:

[0042] 1- Light source assembly;

[0043] 11- Light source;

[0044] 2-Detection component;

[0045] 21-beam splitter;

[0046] 22-Balanced detector;

[0047] 221 - first photodiode;

[0048] 222-first diverter;

[0049] 223 - second photodiode;

[0050] 224-second diverter;

[0051] 225-Subtractor;

[0052] 3- Sampling and quantization components;

[0053] 31- first converter;

[0054] 32-second converter;

[0055] 33- third converter;

[0056] 4-Data processing components. DETAILED DESCRIPTION

[0057] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0058] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise," "include," etc. used herein indicate the presence of the features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0059] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0060] When expressions such as "at least one of A, B, and C, etc." are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0061] In the related technologies for quantitatively evaluating the impact of changes (or fluctuations) in the intensity of local oscillator light on the security of quantum communication systems, most of them use additional optical beam splitters and detectors to split the local oscillator light by a small proportion and then monitor it to defend against possible potential attacks. However, they do not take into account the changes in the wavelength of the local oscillator light and the security issues caused by the changes in the beam splitting ratio of the beam splitter inside the balanced detector caused by the wavelength changes, resulting in hidden dangers in the actual security of the QRNG system based on vacuum fluctuation noise.

[0062] In view of this, the present disclosure provides a quantum random number generator, which provides an initial light signal by setting a light source component, and sets a detection component including a beam splitter and a balanced detector, wherein the beam splitter includes a first input end and a second input end, the first input end is closed so that the first input end receives a vacuum state signal with quantum fluctuations; the second input end receives the initial light signal; the beam splitter is adapted to combine the vacuum state signal with the initial light signal and output a first light signal and a second light signal including the vacuum state signal and the initial light signal, and utilizes a balanced detector to convert the first light signal and the second light signal into a first electrical signal dependent on the first light signal, a second electrical signal dependent on the second light signal, and a second electrical signal dependent on the first electrical signal and the first electrical signal. The invention relates to a third electrical signal of the second electrical signal, and utilizes a sampling and quantization component to convert the first electrical signal, the second electrical signal and the third electrical signal into a first digital signal, a second digital signal and a third digital signal respectively; utilizes a data processing component to obtain the optical wavelength of the initial optical signal, the intensity of the initial optical signal and the splitting ratio of the beam splitter according to the first digital signal and the second digital signal, and obtains a final random number according to the third digital signal. It is possible to obtain in real time the changes in the intensity and wavelength of the local oscillator light used to provide the initial optical signal and the changes in the splitting ratio of the beam splitter caused by the wavelength change, and it is possible to evaluate in real time the extractable randomness of the quantum random number generator system, thereby improving the actual security of the quantum random number generator system.

[0063] Figure 1 The figure schematically shows a block diagram of a quantum random number generator according to an embodiment of the present disclosure.

[0064] According to some embodiments of the present disclosure, Figure 1As shown, the quantum random number generator includes a light source component 1, a detection component 2, a sampling and quantization component 3, and a data processing component 4. The light source component 1 is adapted to provide an initial optical signal; the detection component 2 includes a beam splitter 21 and a balanced detector 22. The beam splitter 21 includes a first input end and a second input end, wherein the first input end is closed so that the first input end receives a vacuum state signal containing quantum fluctuations; the second input end receives the initial optical signal; the beam splitter 21 is adapted to combine the vacuum state signal with the initial optical signal and output a first optical signal and a second optical signal comprising the vacuum state signal and the initial optical signal; the balanced detector 22 is adapted to convert the first optical signal and the second optical signal into a first electrical signal dependent on the first optical signal, a second electrical signal dependent on the second optical signal, and a third electrical signal dependent on the first electrical signal and the second electrical signal. The sampling and quantization component 3 is adapted to convert the first electrical signal, the second electrical signal and the third electrical signal into a first digital signal, a second digital signal and a third digital signal, respectively; the data processing component 4 is adapted to obtain the optical wavelength of the initial optical signal, the intensity of the initial optical signal and the splitting ratio of the beam splitter 21 according to the first digital signal and the second digital signal, and to obtain the final random number according to the third digital signal.

[0065] According to some embodiments of the present disclosure, a light source component 1 is provided to provide an initial light signal, and a detection component 2 including a beam splitter 21 and a balanced detector 22 is provided. The beam splitter 21 includes a first input end and a second input end, the first input end is closed so that the first input end receives a vacuum state signal with quantum fluctuations; the second input end receives the initial light signal; the beam splitter 21 is adapted to combine the vacuum state signal with the initial light signal and output a first light signal and a second light signal including the vacuum state signal and the initial light signal, and the balanced detector 22 is used to convert the first light signal and the second light signal into a first electrical signal dependent on the first light signal, a second electrical signal dependent on the second light signal, and a third electrical signal dependent on the first electrical signal and the second electrical signal; and a sampling and quantization component 3 is used to obtain a first light signal and a second light signal. The first electrical signal, the second electrical signal, and the third electrical signal are converted into a first digital signal, a second digital signal, and a third digital signal, respectively; the data processing component 4 is used to obtain the optical wavelength of the initial optical signal, the intensity of the initial optical signal, and the splitting ratio of the beam splitter according to the first digital signal and the second digital signal, and the final random number is obtained according to the third digital signal. The changes in the intensity and wavelength of the local oscillator light used to provide the initial optical signal and the changes in the splitting ratio of the beam splitter 21 caused by the wavelength change can be obtained in real time, and the extractable randomness of the quantum random number generator system can be evaluated in real time. At the same time, it has the ability to resist attacks by eavesdroppers on the intensity, wavelength, and splitting ratio of the local oscillator light providing the initial optical signal, thereby improving the actual security of the quantum random number generator system.

[0066] According to some embodiments of the present disclosure, light source assembly 1 includes light source 11, which comprises a laser with stable frequency and phase. Light source 11 generates coherent light, which refers to light that maintains the same phase difference during propagation and can undergo interference. This coherent light serves as the local oscillator light of detection assembly 2, providing a stable reference signal, i.e., the initial optical signal. The local oscillator light can also be precisely mixed or differentially operated with the signal light. The initial optical signal is coupled into the second input port of beam splitter 21.

[0067] According to some embodiments of the present disclosure, no light source is placed at the first input end of the beam splitter 21. Instead, the first input end is sealed with a conventional fiber pigtail port protective cap, allowing the first input end to receive a vacuum state signal containing quantum fluctuations. That is, the first input end of the beam splitter 21 is used to receive the vacuum state, which is equivalent to inputting a vacuum quantum state into the first input end of the beam splitter 21. The beam splitter 21 is a 2×2 beam splitter, which further includes a first output end and a second output end. The first optical signal output from the first output end is input into the first photodiode 221, and the second optical signal output from the second output end is input into the second photodiode 223.

[0068] According to some embodiments of the present disclosure, a vacuum state signal is received via the first input of beam splitter 21. As the entropy source for a quantum random number generator, the vacuum state exhibits natural quantum fluctuations, and measuring its canonical component can yield high-speed random numbers. Furthermore, because the vacuum state exists naturally, it requires no additional light source input and cannot be controlled or interfered with. Therefore, under ideal detection conditions, the random numbers generated by measuring and extracting it are truly random and highly reliable.

[0069] According to some embodiments of the present disclosure, the data processor used in the data processing component 4 may be an algorithm or device commonly used in the art for post-processing digital signals.

[0070] According to some embodiments of the present disclosure, the aforementioned quantum random number generator requires no additional components, resulting in low system complexity and ease of implementation. Furthermore, the aforementioned quantum random number generator can monitor both the intensity of the local oscillator light and the splitting ratio of the beam splitter, which is sensitive to the input light wavelength, in real time. While addressing potential security vulnerabilities introduced by variations in the local oscillator light wavelength, it can also adjust system parameters in real time based on the beam splitter ratio to optimize system performance and improve the random number generation rate.

[0071] According to some embodiments of the present disclosure, the conditional minimum entropy is obtained based on the optical wavelength of the initial optical signal, the intensity of the initial optical signal, the splitting ratio of the beam splitter 21, and the third digital signal, thereby obtaining the lower bound of the extractable randomness of the quantum random number generator.

[0072] According to some embodiments of the present disclosure, the randomness of quantum random numbers is directly derived from fundamental properties of quantum physics, such as the uncertainty of quantum states and the random collapse of superposition states. These properties ensure that quantum random number generators can generate truly random numbers. The extractable randomness of a quantum random number generator refers to the randomness that can be effectively extracted from the random numbers generated through quantum mechanical processes (such as the collapse of quantum states and the uncertainty principle) and used in various application scenarios.

[0073] According to some embodiments of the present disclosure, the randomness of a quantum random number generator is evaluated by utilizing conditional minimum entropy. The greater the conditional minimum entropy, the better the randomness. When sampling does not introduce new data correlations, the actual random generation rate of the quantum random number generator system can be obtained by normalizing the conditional minimum entropy and multiplying it by the sampling rate of the third converter 33. The lower bound of the extractable randomness is the minimum actual random generation rate. Therefore, the lower bound of the extractable randomness of the quantum random number generator system can be calculated based on the conditional minimum entropy calculation formula.

[0074] Figure 2 The figure schematically shows the working principle of the quantum random number generator according to an embodiment of the present disclosure.

[0075] According to some embodiments of the present disclosure, Figure 2 As shown, the balanced detector 22 includes a first photodiode 221, a first splitter 222, a second photodiode 223, a second splitter 224, and a subtractor 225. The first photodiode 221 is adapted to obtain a fourth electrical signal based on the first optical signal; the first splitter 222 is adapted to proportionally split the fourth electrical signal into a first electrical signal and a first sub-electrical signal; the second photodiode 223 is adapted to obtain a fifth electrical signal based on the second optical signal; the second splitter 224 is adapted to proportionally split the fifth electrical signal into a second electrical signal and a second sub-electrical signal; and the subtractor 225 is adapted to perform differential processing on the first sub-signal and the second sub-signal to output a third electrical signal.

[0076] According to some embodiments of the present disclosure, the subtractor 225 subtracts the first sub-signal from the second sub-signal, i.e., performs difference processing, and the difference between the two current signals of the first sub-signal and the second sub-signal corresponds to the position component value of the vacuum state.

[0077] According to some embodiments of the present disclosure, as the vacuum state fluctuates, the difference between the first and second sub-signals will also fluctuate accordingly. This fluctuation is due to the quantum nature of the vacuum state. Therefore, the random number ultimately extracted from the difference between the first and second sub-signals based on these vacuum state fluctuations is inherently truly random.

[0078] According to some embodiments of the present disclosure, the intensity of the first electrical signal is weaker than the first sub-electrical signal, and the intensity of the second electrical signal is weaker than the intensity of the second sub-electrical signal. By processing the fourth electrical signal and the fifth electrical signal in proportion, and with the intensity of the first electrical signal being weaker than the first sub-electrical signal and the intensity of the second electrical signal being weaker than the intensity of the second sub-electrical signal, the quantum random number generator can obtain changes in the intensity and wavelength of the local oscillator light and changes in the beam splitting ratio of the beam splitter caused by changes in the wavelength through the fourth and fifth electrical signals, and can also obtain quantum random numbers through the third electrical signal, thereby enabling real-time evaluation of the extractable randomness of the quantum random number generator system, thereby improving the actual security of the quantum random number generator system.

[0079] According to some embodiments of the present disclosure, the ratio of the intensity of the first electrical signal to the intensity of the first sub-electrical signal satisfies The ratio of the intensity of the second electrical signal to the intensity of the second sub-electrical signal satisfies 1: .

[0080] According to some embodiments of the present disclosure, the ratio of the intensity of the fourth electrical signal to the intensity of the first electrical signal satisfies : 1, and The ratio of the intensity of the fifth electrical signal to the intensity of the second electrical signal satisfies : 1, and .

[0081] According to some optional embodiments of the present disclosure, .

[0082] According to some embodiments of the present disclosure, Figure 2 As shown, the sampling and quantization component 3 includes a first converter 31, a second converter 32, and a third converter 33. The first converter 31 is adapted to convert a first electrical signal into a first digital signal; the second converter 32 is adapted to convert a second electrical signal into a second digital signal; and the third converter 33 is adapted to convert a third electrical signal into a third digital signal. The first converter 31, the second converter 32, and the third converter 33 are all capable of amplifying the first electrical signal, the second electrical signal, and the third electrical signal.

[0083] According to some embodiments of the present disclosure, a sampling and quantization component 3 including a first converter 31, a second converter 32, and a third converter 33 is provided to convert the first, second, and third electrical signals into corresponding first, second, and third digital signals, respectively. Digital signal processing techniques can be used to accurately filter, amplify, and remove noise from the digital signals, thereby improving the accuracy and reliability of random numbers. Furthermore, digital signals are easy to store and transmit, can be recorded in computers or other digital storage media, and can also be transmitted remotely via channels such as networks, enabling the widespread application of quantum random numbers in various application scenarios.

[0084] According to some embodiments of the present disclosure, the third digital signal output by the third converter 33 can be used as the original data of the quantum random number. After the third digital signal is post-processed by the data processing component 4, the processed data is used as the quantum random number.

[0085] According to some embodiments of the present disclosure, the first converter 31 , the second converter 32 , and the third converter 33 can convert current signals into voltage signals, and also have the ability to amplify voltage signals.

[0086] According to some embodiments of the present disclosure, the conversion gain coefficients of the first converter 31 and the second converter 32 are: and ,and .

[0087] According to some embodiments of the present disclosure, the first digital signal is , the second digital signal is , the third digital signal is .

[0088] According to some embodiments of the present disclosure, the detection component 2 further includes an adjustable attenuator, which is adapted to control the intensity of the first optical signal and the second optical signal so that the intensity of the fourth electrical signal is the same as the intensity of the fifth electrical signal.

[0089] According to some embodiments of the present disclosure, by providing an adjustable attenuator (not shown in the figure) inside the detection component 2, the intensity of the first optical signal and the second optical signal can be controlled so that the intensity of the fourth electrical signal and the intensity of the fifth electrical signal are the same, thereby ensuring the consistency of the photoelectric conversion efficiency or response characteristics of the first photodiode 221 and the second photodiode 223, and accurately reflecting the current changes caused by the intensity changes of the coherent light (local oscillation light) provided by the light source 11, thereby improving the accuracy of the measurement.

[0090] According to some embodiments of the present disclosure, the transmission coefficient of the beam splitter 21 is obtained according to the first digital signal and the second digital signal. The transmission coefficient of the beam splitter 21 can be expressed as formula (1):

[0091] (1),

[0092] in, represents the transmission coefficient of the beam splitter 21; represents an average value of the first digital signal; represents an average value of the second digital signal; represents the detection efficiency difference coefficient between the first photodiode and the second photodiode; is the ratio of the overall conversion gain coefficient of the fourth electrical signal through the first splitter 222 and the first converter 31 to the overall conversion gain coefficient of the fifth electrical signal through the second splitter 224 and the second converter 32; is the wavelength of the initial optical signal.

[0093] According to some embodiments of the present disclosure, the transmission coefficient of the beam splitter 21 is a parameter related to the wavelength of the initial light signal (local oscillator light). When the transmission coefficient of the beam splitter 21 is determined, the wavelength of the current local oscillator light can be determined by consulting the technical parameter table (data sheet) of the beam splitter, and the detection efficiency of the first photodiode 221 can be determined by combining the response curves of the first photodiode 221 and the second photodiode 223. and the detection efficiency of the second photodiode 223 .

[0094] According to some embodiments of the present disclosure, the average optical power of the initial optical signal satisfies formula (2):

[0095] (2),

[0096] in, Represents the average optical power of the initial optical signal; , is the detection efficiency of the first photodiode 221; is the detection efficiency of the second photodiode 223; is the overall conversion gain coefficient of the fourth electrical signal after passing through the first splitter 222 and the first converter 31; is the detection efficiency difference coefficient between the first photodiode 221 and the second photodiode 223.

[0097] According to some embodiments of the present disclosure, the conversion gain coefficients of the first converter 31 and the second converter 32 are equal, that is, In the case of , and the ratio of the intensity of the fourth electrical signal to the intensity of the first electrical signal is the same as the ratio of the intensity of the fifth electrical signal to the intensity of the second electrical signal, that is, At this time, the overall conversion gain coefficient of the fourth electrical signal after the first shunt 222 and the first converter 31 satisfies The overall conversion gain coefficient of the fifth electrical signal after the second shunt 224 and the second converter 32 satisfies , .

[0098] According to some embodiments of the present disclosure, the beam splitter 21 has a beam splitting ratio that satisfies formula (3):

[0099] (3),

[0100] in, represents the splitting ratio of the beam splitter 21; represents the transmission coefficient of the beam splitter 21.

[0101] According to some embodiments of the present disclosure, the first digital signal and the second digital signal , can obtain the intensity of the local oscillator light in real time, that is, the average optical power of the local oscillator light and the transmission coefficient of the beam splitter 21 Therefore, the quantum random number generator system can realize real-time monitoring of the intensity, wavelength and beam splitting ratio of the local oscillator light of the QRNG system based on vacuum fluctuation noise. When the eavesdropper launches a local oscillator light intensity fluctuation attack and a local oscillator light wavelength attack, the eavesdropper's eavesdropping behavior can be effectively discovered by real-time measurement and statistics of the monitoring signal. After the eavesdropping behavior is discovered, the operating state of the quantum random number generator system is adjusted in real time, that is, the third converter 33 re-collects the third electrical signal output by the subtractor 225, and re-obtains the third digital signal , and calculate its mean and variance, recorded as and , and then obtain the actual conditional minimum entropy of the actual quantum random number generator system, and normalize the conditional minimum entropy and multiply it by the sampling rate of the third converter 33 to obtain the actual random generation rate of the quantum random number generator system.

[0102] According to some embodiments of the present disclosure, since the random numbers generated by this scheme are obtained by evaluating the real-time conditional minimum entropy of the system and performing corresponding data post-processing, the corresponding random number generation rate is also obtained through real-time conditional minimum entropy calculation, and the actual conditional minimum entropy is taken into account The changes in the local oscillator light intensity, wavelength and beam splitter splitting ratio introduced by the eavesdropper are taken into account and the real-time measurement and statistics of the relevant parameters are performed and then calculated. Therefore, the quantum random number generator has high security and is capable of resisting attacks by eavesdroppers on the local oscillator light intensity, wavelength and beam splitter splitting ratio.

[0103] Those skilled in the art will appreciate that the features described in the various embodiments and / or claims of this disclosure may be combined and / or coupled in various ways, even if such combinations and / or couplings are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure may be combined and / or coupled in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or couplings are intended to fall within the scope of this disclosure.

[0104] The embodiments of the present disclosure are described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although each embodiment has been described separately above, this does not mean that the measures in each embodiment cannot be used in combination to advantage. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A quantum random number generator, wherein: include: A light source assembly, adapted to provide an initial light signal; Detection components, including: A beam splitter, the beam splitter comprising a first input end and a second input end, the first input end being closed so as to receive a vacuum state signal having quantum fluctuations; the second input end receiving the initial light signal; the beam splitter being adapted to combine the vacuum state signal with the initial light signal and output a first light signal and a second light signal including the vacuum state signal and the initial light signal; and a balanced detector adapted to convert the first optical signal and the second optical signal into a first electrical signal dependent on the first optical signal, a second electrical signal dependent on the second optical signal, and a third electrical signal dependent on the first electrical signal and the second electrical signal; a sampling and quantization component adapted to convert the first electrical signal, the second electrical signal, and the third electrical signal into a first digital signal, a second digital signal, and a third digital signal, respectively; and a data processing component adapted to obtain the optical wavelength of the initial optical signal, the intensity of the initial optical signal, and the splitting ratio of the beam splitter according to the first digital signal and the second digital signal, and to obtain a final random number according to the third digital signal; Wherein, the balanced detector comprises: a first photodiode, adapted to obtain a fourth electrical signal based on the first optical signal; a first splitter, adapted to divide the fourth electrical signal into a first electrical signal and a first sub-electrical signal in proportion; a second photodiode, adapted to obtain a fifth electrical signal based on the second optical signal; a second splitter, adapted to divide the fifth electrical signal into a second electrical signal and a second sub-electrical signal in proportion; and a subtractor, adapted to perform difference processing on the first sub-electrical signal and the second sub-electrical signal to output a third electric signal; The ratio of the intensity of the first electrical signal to the intensity of the first sub-electrical signal satisfies The ratio of the intensity of the second electrical signal to the intensity of the second sub-electrical signal satisfies , the intensity of the first electrical signal is weaker than the intensity of the first sub-electrical signal, and the intensity of the second electrical signal is weaker than the intensity of the second sub-electrical signal.

2. The quantum random number generator according to claim 1, wherein The conditional minimum entropy is obtained according to the optical wavelength of the initial optical signal, the intensity of the initial optical signal, the splitting ratio of the beam splitter and the third digital signal, thereby obtaining a lower bound of the extractable randomness of the quantum random number generator.

3. The quantum random number generator according to claim 1, wherein The sampling and quantization components include: a first converter, adapted to convert the first electrical signal into a first digital signal; a second converter adapted to convert the second electrical signal into a second digital signal; and a third converter, adapted to convert the third electrical signal into a third digital signal; The first converter, the second converter and the third converter are all capable of amplifying the first electrical signal, the second electrical signal and the third electrical signal.

4. The quantum random number generator according to any one of claims 1 to 3, wherein: The detection component further includes an adjustable attenuator, which is adapted to control the intensities of the first optical signal and the second optical signal so that the intensity of the fourth electrical signal is the same as the intensity of the fifth electrical signal.

5. The quantum random number generator according to claim 4, wherein: According to the first digital signal and the second digital signal, a transmission coefficient of the beam splitter is obtained. The transmission coefficient of the beam splitter can be expressed as formula (1): （1）， in, represents the transmission coefficient of the beam splitter; represents an average value of the first digital signal; represents an average value of the second digital signal; represents a detection efficiency difference coefficient between the first photodiode and the second photodiode; is a ratio of the overall conversion gain coefficient of the fourth electrical signal through the first splitter and the first converter to the overall conversion gain coefficient of the fifth electrical signal through the second splitter and the second converter; is the wavelength of the initial optical signal.

6. The quantum random number generator according to claim 5, wherein: The average optical power of the initial optical signal satisfies formula (2): （2）， in, represents the average optical power of the initial optical signal; , is the detection efficiency of the first photodiode; is the detection efficiency of the second photodiode; is the overall conversion gain coefficient of the fourth electrical signal through the first splitter and the first converter; is the detection efficiency difference coefficient between the first photodiode and the second photodiode.

7. The quantum random number generator according to claim 6, wherein: The beam splitting ratio of the beam splitter satisfies formula (3): （3）， in, represents the splitting ratio of the beam splitter; represents the transmission coefficient of the beam splitter.

8. The quantum random number generator according to claim 7, wherein: The beam splitter is a 2×2 beam splitter, and the 2×2 beam splitter further includes a first output end and a second output end, and the first optical signal outputted from the first output end is inputted into the first photodiode; The second optical signal outputted from the second output terminal is inputted into the second photodiode.

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