Encryption method, system, device and storage medium based on reconfigurable intelligent surface

Abstract

The application provides an encryption method, system, device and storage medium based on a reconfigurable intelligent surface, wherein the method comprises the following steps: acquiring channel state information between nodes of two communication parties, wherein the communication nodes used by the two communication parties comprise at least one active reconfigurable intelligent surface; obtaining an optimal parameter set under a maximum key generation rate state based on the channel state information; the two communication parties exchange the same pilot signal according to the optimal parameter set, and quantize the phase of a received signal into key bits; and the two communication parties perform information negotiation to determine that the same key bits are used for encrypted communication. The application can introduce an active reconfigurable intelligent surface for physical layer key generation, increase channel gain to further improve the physical layer key generation rate, and maximize the key generation rate under the premise of meeting the total power constraint.

Description

Technical Field

[0001] This invention relates to the field of communication positioning, and more specifically, to encryption methods, systems, devices, and storage media based on reconfigurable smart surfaces. Background Technology

[0002] Due to the openness and broadcast nature of wireless signal propagation, potential eavesdropping nodes in the vicinity can eavesdrop on legitimate nodes during communication. Unlike traditional high-level encryption methods, physical layer key generation technology utilizes the reciprocity and uniqueness of the wireless channel to generate keys for encrypting communication information. In physical layer key generation technology, a higher key generation rate means that both communicating parties have more keys for encryption, implying higher communication security. However, due to the fading effect of the wireless channel, a relatively low key generation rate is one of the bottlenecks of physical layer key generation technology.

[0003] Reconfigurable Intelligent Surfaces (RIS) are a popular communication technology in recent years. They can intelligently modify wireless channels to improve communication performance at a low cost. RIS technology is often used to improve signal blind spots in communication environments. RIS has the ability to reconfigure the wireless propagation environment and can be used to enhance coverage in blind spots of communication systems, especially high-frequency communication systems. RIS is a revolutionary new technology that can intelligently reconfigure the wireless propagation environment by integrating a large number of low-cost passive reflective elements on a plane, thereby significantly improving the performance of wireless communication networks. Specifically, different elements of the RIS can independently reflect incident signals by controlling their amplitude and / or phase, thereby collaboratively achieving fine three-dimensional (3D) passive beamforming for directional signal enhancement or nulling. However, RIS typically produces main lobes and side lobes in different directions during use. The largest radiating beam is called the main lobe, and the smaller beams next to the main lobe are called side lobes. The radiation pattern of a RIS usually has two or more lobes, with the lobe with the largest radiation intensity called the main lobe, and the remaining lobes called side lobes. The angle between two points on either side of the main lobe’s maximum radiation direction, where the radiation intensity decreases by 3dB (power density decreases by half), is defined as the beamwidth (also known as the main lobe width or half-power angle).

[0004] Traditional passive RIS can enhance the wireless channel by creating a line-of-sight path between communication nodes, thereby increasing the physical layer key generation rate. However, due to the "multiplicative fading" of the RIS path, the gain brought to the system by traditional passive RIS is limited. Intelligent metasurface technology theoretically brings a signal-to-noise ratio gain proportional to the square of the number of surface units (corresponding to higher system capacity), which is one of the main reasons for its popularity. However, this technology also introduces the "multiplicative fading" effect, meaning that the large-scale fading of the RIS reflection path is proportional to the product of the path lengths from the RIS to the two communicating parties, which will severely reduce the channel gain brought by the RIS. Therefore, RIS can only achieve considerable capacity gain in atypical communication scenarios where the direct path is blocked, while in typical communication scenarios with strong direct paths, the actual capacity gain brought by existing passive RIS is negligible (65% capacity gain in atypical scenarios, but only 3% in typical scenarios).

[0005] In view of this, the present invention proposes an encryption method, system, device and storage medium based on a reconfigurable smart surface.

[0006] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0007] To address the problems in the prior art, the present invention aims to provide an encryption method, system, device, and storage medium based on reconfigurable smart surfaces, which overcomes the difficulties of the prior art. It can introduce active reconfigurable smart surfaces for physical layer key generation, and further improve the physical layer key generation rate by increasing the channel gain, thereby maximizing the key generation rate while meeting the total power constraint.

[0008] Embodiments of the present invention provide an encryption method based on a reconfigurable smart surface, comprising the following steps:

[0009] The channel state information between each node of the two communicating parties is obtained, wherein the communication nodes used by the two communicating parties include at least one active reconfigurable smart surface;

[0010] Based on the channel state information, the optimal set of parameters for achieving the maximum key generation rate is obtained.

[0011] The two communicating parties exchange the same pilot signal based on an optimal parameter set, and quantize the received signal into key bits based on the phase of the received signal; and

[0012] The two communicating parties negotiate and agree to use the same key bits for encrypted communication.

[0013] Preferably, the acquisition of channel state information between the nodes of the two communicating parties includes at least one active reconfigurable smart surface between the communication nodes used by the two communicating parties, comprising:

[0014] Receive key generation requests from both parties in communication, where the communication nodes used by both parties include at least one active reconfigurable smart surface;

[0015] Obtain channel status information between each node.

[0016] Preferably, obtaining the optimal parameter set for achieving the maximum key generation rate based on the channel state information further includes:

[0017] The signal-to-noise ratio of the received signal is maximized and the key generation rate is maximized when all reflection channels of an active reconfigurable smart surface are phase-aligned.

[0018] Preferably, obtaining the optimal parameter set for achieving the maximum key generation rate based on the channel state information includes:

[0019] The optimal reflection phase of the active reconfigurable smart surface is obtained when the signal-to-noise ratio of the received signal is maximized;

[0020] The optimal reflection amplitude of the active reconfigurable smart surface is obtained when the signal-to-noise ratio of the received signal is maximized;

[0021] The optimal transmission power of the active reconfigurable smart surface is obtained when the signal-to-noise ratio of the received signal is maximized;

[0022] The optimal quantization level of the active reconfigurable smart surface is obtained when the signal-to-noise ratio of the received signal is maximized.

[0023] Preferably, obtaining the optimal reflection phase of the active reconfigurable smart surface when the signal-to-noise ratio of the received signal is maximized further includes:

[0024] The maximum key generation rate is positively correlated with the reflection amplitude of the active reconfigurable smart surface.

[0025] Preferably, the two communicating parties exchange the same pilot signal according to an optimal parameter set, and quantize the received signal into key bits based on the phase of the received signal, including:

[0026] The reflection coefficient of the active reconfigurable smart surface is adjusted according to the optimal reflection phase and the optimal reflection amplitude.

[0027] The two communicating parties exchange pilot signals according to the optimal transmission power;

[0028] Estimate the phase of the received signal;

[0029] The phase of the received signal is quantized into key bits according to the optimal quantization level.

[0030] Preferably, the two communicating parties negotiate and determine to use the same key bits for encrypted communication, including:

[0031] The two communicating parties negotiate information to obtain the key bits with the smallest error;

[0032] By using privacy amplification to remove leaked information, a physical layer key is generated.

[0033] Encrypted communication is achieved through physical layer keys.

[0034] Embodiments of the present invention also provide an encryption system based on a reconfigurable smart surface for implementing the above-described encryption method based on a reconfigurable smart surface. The encryption system based on a reconfigurable smart surface includes:

[0035] The status acquisition module acquires the channel status information between each node of the two communicating parties, and the communication nodes used by the two parties include at least one active reconfigurable smart surface.

[0036] The optimal parameter module obtains the optimal set of parameters to achieve the maximum key generation rate based on channel state information.

[0037] The key bit module allows both communicating parties to exchange the same pilot signal based on an optimal parameter set, and quantizes the received signal into key bits according to its phase; and

[0038] The encrypted communication module allows both communicating parties to negotiate and agree to use the same key bits for encrypted communication.

[0039] Embodiments of the present invention also provide an encryption device based on a reconfigurable smart surface, comprising:

[0040] processor;

[0041] Memory, which stores the processor's executable instructions;

[0042] The processor is configured to execute the steps of the encryption method based on the reconfigurable smart surface described above by executing executable instructions.

[0043] Embodiments of the present invention also provide a computer-readable storage medium for storing a program that, when executed, implements the steps of the encryption method based on reconfigurable smart surfaces described above.

[0044] The purpose of this invention is to provide an encryption method, system, device and storage medium based on reconfigurable smart surfaces, which can introduce active RIS (active reconfigurable smart surfaces) for physical layer key generation, increase the channel gain to further improve the physical layer key generation rate, and maximize the key generation rate while satisfying the total power constraint. Attached Figure Description

[0045] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

[0046] Figure 1 This is a flowchart of the encryption method based on reconfigurable smart surfaces according to the present invention.

[0047] Figure 2 This is a flowchart illustrating step S110 in an embodiment of the encryption method based on reconfigurable smart surfaces of the present invention.

[0048] Figure 3 This is a flowchart illustrating step S120 in an embodiment of the encryption method based on reconfigurable smart surfaces of the present invention.

[0049] Figure 4 This is a flowchart illustrating step S130 in an embodiment of the encryption method based on reconfigurable smart surfaces of the present invention.

[0050] Figure 5 This is a flowchart illustrating step S140 in an embodiment of the encryption method based on reconfigurable smart surfaces of the present invention.

[0051] Figure 6 This is a schematic diagram of a scenario in which the encryption method based on reconfigurable smart surfaces of the present invention is implemented.

[0052] Figure 7 This is a schematic diagram of a system implementing the encryption method based on reconfigurable smart surfaces of the present invention.

[0053] Figure 8 This is a schematic diagram of the state acquisition module in an embodiment of the encryption system based on a reconfigurable smart surface of the present invention.

[0054] Figure 9 This is a schematic diagram of the optimal parameter module in an embodiment of the encryption system based on a reconfigurable smart surface of the present invention.

[0055] Figure 10 This is a schematic diagram of the key bit module in an embodiment of the encryption system based on a reconfigurable smart surface of the present invention.

[0056] Figure 11This is a schematic diagram of the encrypted communication module in an embodiment of the encryption system based on a reconfigurable smart surface of the present invention.

[0057] Figure 12 This is a schematic diagram of the encryption device based on a reconfigurable smart surface according to the present invention. Detailed Implementation

[0058] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed herein. This application can also be implemented or applied through other different specific embodiments, and various details in this application can be modified or changed according to different viewpoints and application systems without departing from the spirit of this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0059] The embodiments of this application will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily implement the application. This application may be embodied in many different forms and is not limited to the embodiments described herein.

[0060] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics represented in connection with that embodiment or example, which are included in at least one embodiment or example of this application. Furthermore, the specific features, structures, materials, or characteristics represented may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate different embodiments or examples represented in this application, as well as features of different embodiments or examples.

[0061] Furthermore, the terms "first" and "second" are used for illustrative purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the representation of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0062] For the purpose of clearly describing this application, devices that are not relevant to the description are omitted, and the same or similar components throughout the specification are given the same reference numerals.

[0063] Throughout this specification, when it is said that a device is "connected" to another device, this includes not only "direct connection" but also "indirect connection" by placing other components in between. Furthermore, when it is said that a device "comprises" a certain constituent element, unless otherwise stated otherwise, this does not exclude other constituent elements, but rather implies that other constituent elements may be included.

[0064] When we say that a device is "above" another device, this can mean that it is directly above the other device, or it can mean that other devices are present in between. Conversely, when we say that a device is "directly" "above" another device, there are no other devices present in between.

[0065] Although the terms first, second, etc., are used in some instances herein to refer to various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, first interface and second interface, etc., are used. Furthermore, as used herein, the singular forms “a,” “an,” and “the” are intended to also include the plural forms unless the context indicates otherwise. It should be further understood that the terms “comprising,” “including,” indicate the presence of features, steps, operations, elements, components, items, kinds, and / or groups, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, kinds, and / or groups. The terms “or” and “and / or” as used herein are interpreted as inclusive, or mean any one or any combination thereof. Thus, “A, B, or C” or “A, B, and / or C” means “any one of: A; B; C; A and B; A and C; B and C; A, B, and C.” Exceptions to this definition will only occur if the combination of elements, functions, steps, or operations is inherently mutually exclusive in some way.

[0066] The technical terms used herein are for reference only to specific embodiments and are not intended to limit the scope of this application. The singular form used herein includes the plural form unless the statement explicitly indicates otherwise. The word "comprising" as used in the specification means to specify a particular characteristic, region, integer, step, operation, element, and / or component, and does not exclude the presence or addition of other characteristics, regions, integers, steps, operations, elements, and / or components.

[0067] Although not explicitly defined, all terms, including technical and scientific terms used herein, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. Terms defined in commonly used dictionaries shall be further interpreted as having a meaning consistent with the relevant technical literature and the content of this present application, and shall not be over-interpreted as having an ideal or overly formulaic meaning unless otherwise defined.

[0068] Figure 1This is a flowchart of the encryption method based on reconfigurable smart surfaces according to the present invention. Figure 1 As shown, the encryption method based on reconfigurable smart surfaces of the present invention includes the following steps:

[0069] S110. Obtain channel state information between each node of the two communicating parties, wherein the communication nodes used by both parties include at least one active reconfigurable smart surface. Unlike existing passive RIS, which can only passively reflect signals and cannot amplify them, the active RIS of this invention integrates additional reflective power amplifiers on each (or part of) RIS unit, thereby regulating the reflected signal while amplifying it with high gain, thus effectively reducing the impact of "multiplicative fading". However, at the same time, the active amplification of the transmitted signal will also bring higher energy consumption and thermal noise interference. For active RIS, due to the introduction of active devices, the noise introduced is no longer negligible like that of passive RIS, so its signal model is also significantly different from that of passive RIS. Compared with the common baseline of not deploying RIS, existing passive RIS can only achieve a small amount of capacity gain in typical application scenarios, while the active RIS we propose can obtain a huge amount of significant capacity gain, thus effectively overcoming the "multiplicative fading" effect of RIS. Compared to existing passive RIS, active RIS can achieve significant performance gains in both typical and atypical scenarios, far exceeding the performance gains achievable by passive RIS, and is therefore expected to be widely used in future 6G systems.

[0070] S120. Based on channel state information, obtain the optimal parameter set for achieving the maximum key generation rate. This invention jointly optimizes the RIS reflection phase, RIS reflection amplitude, transmission power, and quantization level, and proposes an alternating optimization algorithm to decouple the original mixed-integer nonlinear programming problem (MINLP) into four sub-problems for iterative solution, thereby maximizing the key generation rate while satisfying the total power consumption constraint.

[0071] S130. Both communicating parties send the same pilot signal to each other based on the optimal parameter set, and quantize the received signal into key bits according to the phase of the received signal.

[0072] S140. The two communicating parties negotiate and agree to use the same key bits for encrypted communication.

[0073] This invention addresses the low key generation rate caused by the "multiplication fading" of traditional passive RIS (Resilient Surface Arrangement). It introduces an active RIS to assist in key generation, proposing an active RIS-assisted physical layer key generation scheme. Furthermore, it addresses the additional reflection noise and energy consumption issues associated with active RIS. By introducing an active RIS (Active Reconfigurable Smart Surface) for physical layer key generation and increasing channel gain, the invention further enhances the physical layer key generation rate, maximizing the key generation rate while satisfying total power constraints.

[0074] Figure 2 This is a flowchart illustrating step S110 in an embodiment of the encryption method based on reconfigurable smart surfaces of the present invention. Figure 3 This is a flowchart illustrating step S120 in an embodiment of the encryption method based on reconfigurable smart surfaces of the present invention. Figure 4 This is a flowchart illustrating step S130 in an embodiment of the encryption method based on reconfigurable smart surfaces of the present invention. Figure 5 This is a flowchart illustrating step S140 in an embodiment of the encryption method based on reconfigurable smart surfaces of the present invention. Figures 2 to 5 As shown, in Figure 1 In the embodiment, based on steps S110, S120, S130, and S140, step S110 is replaced by S111 and S112, step S120 is replaced by S121, S122, S123, and S124, step S130 is replaced by S131, S132, S133, and S134, and step S140 is replaced by S141, S142, and S143. The following describes each step:

[0075] S111. Receive a key generation request from both parties communicating, wherein the communication nodes used by both parties include at least one active reconfigurable smart surface.

[0076] S112. Obtain Channel State Information (CSI) between nodes. Channel State Information, in the field of wireless communication, refers to the channel attributes of the communication link. It describes the signal attenuation factors on each transmission path, i.e., the value of each element in the channel gain matrix H, such as signal scattering, environmental fading (multipath fading or shadowing fading), and power decay of distance. CSI allows the communication system to adapt to current channel conditions, providing a guarantee for high-reliability and high-speed communication in multi-antenna systems. Generally, the receiver evaluates the CSI and quantizes it, feeding it back to the transmitter (in time-division duplex systems, reverse evaluation is required).

[0077] S121. Obtain the optimal reflection phase of the active reconfigurable smart surface when the signal-to-noise ratio (SNR) of the received signal is maximized. The SNR, or S / N (signal-noise ratio), refers to the ratio of signal to noise in an electronic device or system. The signal here refers to the electronic signal from outside the device that needs to be processed by it, while the noise refers to irregular additional signals (or information) generated after passing through the device that are not present in the original signal and do not change with the original signal. The reflection coefficient includes the reflection phase and reflection amplitude. The hardware implementation of the reconfigurable smart surface is based on the concept of a "meta-surface," which consists of digitally controllable two-dimensional (2D) metamaterials. Specifically, a subsurface is a planar array composed of a large number of elements or so-called subatomic particles, whose electrical thickness is arranged in order of subwavelengths of the operating frequency of interest. By appropriately designing the elements, including geometry (such as squares or open rings), size / dimensionality, orientation, and arrangement, the individual signal responses (reflection amplitude and phase shift) can be modified accordingly.

[0078] S122. Obtain the optimal reflection amplitude of the active reconfigurable smart surface when the signal-to-noise ratio of the received signal is maximized.

[0079] S123. Obtain the optimal transmit power of the active reconfigurable smart surface when the signal-to-noise ratio of the received signal is maximized. The optimal transmit power is the optimal signal strength transmitted by the device (mobile phone, network card, walkie-talkie) to the base station.

[0080] S124. Obtain the optimal quantization level of the active reconfigurable smart surface when the signal-to-noise ratio of the received signal is maximized. In this invention, the quantization level simply refers to the number of bits of binary data describing the phase of the signal, usually measured in bits, such as 16-bit or 24-bit. A 16-bit quantization level records sound data using 16-bit binary numbers.

[0081] S131. Adjusting the reflection coefficient of the active reconfigurable smart surface according to the optimal reflection phase and optimal reflection amplitude. In wireless communication applications, the reflection coefficient of each unit should be adjustable to adapt to the dynamic wireless channel generated by user mobility, thus requiring real-time reconfigurability. For example, in a single reconfigurable smart surface structure, a PIN diode is embedded in each element. By controlling its bias voltage through a DC feed line, the PIN diode can switch between the "on" and "off" states shown in the equivalent circuit, thereby generating a phase shift difference. Therefore, by setting the corresponding bias voltage through a smart controller, different phase shifts of the RIS element can be achieved independently.

[0082] S132. Both communicating parties exchange pilot signals based on the optimal transmit power. Pilot signals are signals transmitted within a telecommunications network for measurement or monitoring purposes; these signals are typically at a single frequency. In WCDMA systems, pilot signals are used in algorithms such as soft handover, cell selection / reselection, open-loop power control, and pilot pollution. They do not have corresponding logical or transmission channel counterparts and exist within the physical channel. CPICHs are divided into two types: PCPICH, the primary pilot channel (one per cell), used for level testing and channel evaluation, and transmitted throughout the cell; and SCPICHD, a secondary pilot channel (several per cell, not necessarily transmitted throughout the cell). Pilot signals are used for downlink channel phase reference. In TFT, the pilot channel power is constant at 29dBm, and the cell threshold is: Ec >= -115dBm, Ec / I0 > -20dB.

[0083] S133. The communicating parties estimate the phase of the received signal. Phase is the position of a wave at a specific moment in its cycle: a scale indicating whether it is at a crest, trough, or somewhere in between. Phase describes a measure of the change in a signal waveform and is usually expressed in degrees (angles).

[0084] S134. Quantize the phase of the received signal into key bits according to the optimal quantization level.

[0085] S141. The two communicating parties negotiate information to obtain the key bits with the smallest error.

[0086] S142. Both communicating parties remove leaked information through privacy amplification and generate a physical layer key.

[0087] S143. The two communicating parties use a physical layer key for encrypted communication. In this embodiment, an existing or future-invented encryption algorithm can be used to perform encrypted communication using the physical layer key obtained in the above steps. This increases the channel gain to further improve the physical layer key generation rate and maximizes the key generation rate while meeting the total power constraint.

[0088] Figure 6 This is a schematic diagram illustrating a scenario in which the encryption method based on reconfigurable smart surfaces of the present invention is implemented. For example... Figure 6The specific steps of implementing the encryption method based on reconfigurable smart surfaces according to the present invention, as shown in the template, include: In the communication scenario considered in this invention: the two communicating parties (Alice's phone 1 and Bob's phone 2) wish to generate a physical layer key for secure communication, but their direct communication channel is shielded by building 4. An active reconfigurable smart surface 3 (active RIS) composed of N reflective elements is deployed between the communication nodes to assist in generating the physical layer key.

[0089]

[0090] Where, θ n ∈[0,2π] is the phase shift of each reflection unit in the RIS;

[0091] ρ is the reflection amplitude of each reflection unit in the RIS;

[0092] It is the incident channel from user i to RIS;

[0093] It is the reflection channel between RIS and user i.

[0094] The specific process for physical layer key generation is as follows: Within a coherent time interval, both communicating parties first send pilot signals to each other. Due to the reciprocity of the channel, the signals experience the same fading, and both parties receive the same signal. Then, both parties estimate the phase of the received signal and finally quantize the phase into key bits.

[0095] The method of this invention mainly comprises four modules:

[0096] Initialization module: Used for both communicating parties to issue key generation requests and for the system to obtain channel state information. Parameter optimization module: Used to solve the key rate maximization problem and obtain optimal parameters. Key generation module: Used to generate a key based on the obtained optimal parameters. Communication encryption module: Used to encrypt communication based on the key. This invention introduces an active RIS to assist in key generation and performs related optimizations to maximize the key generation rate under power constraints. The specific work focuses on the "parameter optimization" module.

[0097] See Figure 6 As shown, Alice and Bob send pilot signals to each other. The signals received by both parties are represented as

[0098]

[0099]

[0100] Where, p t It's the transmission power. It is Gaussian white noise. Thermal noise introduced by active RIS components, I N It is an N-dimensional unit vector. Due to the reciprocity of the channel, Alice and Bob will receive completely identical signals, so only Bob's signal will be analyzed. Substituting the RIS reflection coefficient, Bob's received signal can be further expressed as:

[0101]

[0102] in,

[0103] This represents the equivalent low-pass response of the nth reflection cascade channel.

[0104] make θ = arctan(r) Q (t)r I The received signal (t) can be further written as:

[0105]

[0106] Here, |h| and θ are the amplitude and phase responses of the channel from Alice to Bob.

[0107] In the above formula, For a valid signal received, This is to prevent interference noise.

[0108] Theoretically, based on the received signal phase, the communicating parties should be able to quantize a completely identical key. However, due to estimation errors in phase estimation, some key bits will be inconsistent, thus reducing the key generation rate. Therefore, to increase the key generation rate, the estimation error must be reduced. The mean square error (CRB) of the minimum estimate of the unbiased estimation can be expressed as:

[0109]

[0110] Where, N s It is the number of sampling points.

[0111] It can be seen that the estimation error depends on the signal-to-noise ratio (SNR) of the received signal. That is, to maximize the key generation rate, the SNR of the received signal must be maximized.

[0112] Alice and Bob each performed uniform quantization on the estimated signal phase, i.e.

[0113]

[0114] Where q = 2k It is a quantization series. Therefore, in each coherent time interval, Alice and Bob can generate at most log2 q key bits.

[0115] Assuming that the phase estimate increases with the number of sampling points... (normal distribution), It is the estimation error.

[0116] Assume θ falls within the interval but Falling in the range The probability is

[0117]

[0118] The probability that Alice and Bob's quantized values ​​fall within the same interval is:

[0119] P A (θ) is symmetric about the central axis of the interval containing θ, due to the design... Much less than 1, therefore It is highly likely that it falls within the same interval as θ, and can be considered as Because of P A (θ) is a group of... Since θ is a periodic function, the overall average quantization agreement rate of Alice and Bob is the same as the average quantization agreement rate of θ falling within a certain interval, which can be expressed as:

[0120] (Mean Value Theorem for Integrals)

[0121] In a channel coherence time T c Within this range, when Alice and Bob's quantization results both fall within the same quantization interval, they can quantize log₂q key bits. Therefore, the key generation rate can be expressed as:

[0122] It is the average quantization consistency probability.

[0123] Key generation rate maximization design

[0124] Based on the above analysis, we can model a problem to maximize the key generation rate under power constraints:

[0125]

[0126] (P1): stq = 2 m m = 0, 1, 2, 3...

[0127]

[0128] The original problem is broken down into the following four sub-problems, which are solved separately.

[0129] Sub-problem 1: Optimize RIS reflection phase

[0130]

[0131] stΦ n,n =1

[0132] The optimal solution to the transformed problem is obtained through calculation, which will not be elaborated here.

[0133] When all reflection channels are phase-aligned, the signal has the maximum received signal-to-noise ratio at the receiver.

[0134]

[0135] The optimal solution to the transformed problem is obtained through calculation, which will not be elaborated here.

[0136] Sub-problem 2: Optimize RIS reflection amplitude

[0137]

[0138] After updating the RIS reflection coefficient, the received signal-to-noise ratio is expressed as:

[0139]

[0140] It can be observed that the SNR is an increasing function of the RIS reflection amplitude. In other words, the key generation rate is an increasing function of the RIS reflection amplitude, therefore the RIS reflection amplitude should be as large as possible.

[0141]

[0142] The optimal solution to the transformed problem is obtained through calculation, which will not be elaborated here.

[0143] Sub-problem 3: Optimize transmission power

[0144]

[0145] stp t ≤P max

[0146] Substituting the optimal solution of subproblem 2 into subproblem 3, subproblem 3 becomes...

[0147]

[0148] stp t ≤P max

[0149] The optimal solution to the transformed problem is obtained through calculation, which will not be elaborated here.

[0150] Subproblem 4: Optimizing the quantization series

[0151]

[0152] stq=2 m m = 0, 1, 2, 3...

[0153] Since the key generation rate first increases and then decreases as the quantization level q increases, the hill-climbing algorithm can be used to find the optimal solution for the quantization level, which will not be elaborated here.

[0154] Thus, the solutions to all four subproblems of the original problem have been completed. In the specific solution process, since each subproblem is independent, the global optimal solution to the entire problem can be obtained simply by solving the optimal solution to each subproblem sequentially, resulting in extremely low algorithmic complexity. Existing or future computational methods can be used to solve the above four subproblems in this invention, which will not be elaborated upon here.

[0155] Compared to existing technologies, current patents only consider introducing passive RIS to assist in physical layer key generation. The RIS's transmission coefficient is randomly varied to increase the randomness of the wireless channel, without optimizing the RIS's reflection coefficient. In contrast, this invention introduces an active RIS for physical layer key generation for the first time, increasing the channel gain to further improve the physical layer key generation rate. Furthermore, by jointly designing the RIS's reflection coefficient, transmission power, and quantization level, this invention fully utilizes the RIS's ability to intelligently reconstruct the wireless propagation environment, maximizing the key generation rate while meeting total power constraints.

[0156] Figure 7 This is a schematic diagram of a system implementing the encryption method based on reconfigurable smart surfaces according to the present invention. Figure 7 As shown, the encryption system based on reconfigurable smart surfaces of the present invention includes, but is not limited to:

[0157] The status acquisition module 51 acquires the channel status information between each node of the two communicating parties, and the communication nodes used by the two parties include at least one active reconfigurable smart surface.

[0158] The optimal parameter module 52 obtains the optimal parameter set under the condition of achieving the maximum key generation rate based on channel state information;

[0159] Key bit module 53: Both communicating parties exchange the same pilot signal based on the optimal parameter set, and quantize the received signal into key bits based on the phase of the received signal; and

[0160] The encrypted communication module 54 allows both communicating parties to negotiate and agree to use the same key bits for encrypted communication.

[0161] The implementation principles of the above modules can be found in the relevant introduction in the encryption method based on reconfigurable smart surfaces, and will not be repeated here.

[0162] The encryption system based on reconfigurable smart surfaces of the present invention can maximize the key generation rate by introducing an active RIS (active reconfigurable smart surface) for physical layer key generation and increasing the channel gain to further improve the physical layer key generation rate while satisfying the total power constraint.

[0163] Figure 8 This is a schematic diagram of the state acquisition module in an embodiment of the encryption system based on a reconfigurable smart surface of the present invention. Figure 9 This is a schematic diagram of the optimal parameter module in an embodiment of the encryption system based on a reconfigurable smart surface of the present invention. Figure 10 This is a schematic diagram of the key bit module in an embodiment of the encryption system based on a reconfigurable smart surface of the present invention. Figure 11 This is a schematic diagram of the encrypted communication module in an embodiment of the encryption system based on a reconfigurable smart surface of the present invention. Figures 8 to 11 As shown, in Figure 7 Based on the device embodiment, the encryption system based on a reconfigurable smart surface of the present invention replaces the state acquisition module 51 with a key request module 511 and a channel state module 512. The optimal parameter module 52 is replaced with a reflection phase module 521, a reflection amplitude module 522, a transmission power module 523, and a quantization level module 524. The key bit module 53 is replaced with a coefficient adjustment module 531, a mutual pilot signal transmission module 532, a phase estimation module 533, and a phase quantization module 534. The encrypted communication module 54 is replaced with an error negotiation module 541, a key generation module 542, and a key usage module 543. Each module is described below:

[0164] The key request module 511 receives key generation requests from both parties in communication, and the communication nodes used by the two parties include at least one active reconfigurable smart surface.

[0165] Channel status module 512: Obtains channel status information between each node.

[0166] The reflection phase module 521 obtains the optimal reflection phase of the active reconfigurable smart surface when the signal-to-noise ratio of the received signal is maximized.

[0167] The reflection amplitude module 522 obtains the optimal reflection amplitude of the active reconfigurable smart surface when the signal-to-noise ratio of the received signal is maximized.

[0168] The transmit power module 523 obtains the optimal transmit power of the active reconfigurable smart surface when the signal-to-noise ratio of the received signal is maximized.

[0169] The quantization level module 524 obtains the optimal quantization level of the active reconfigurable smart surface when the signal-to-noise ratio of the received signal is maximized.

[0170] The coefficient adjustment module 531 adjusts the reflection coefficient of the active reconfigurable smart surface according to the optimal reflection phase and the optimal reflection amplitude.

[0171] The mutual pilot signal module 532 allows both communicating parties to exchange pilot signals according to the optimal transmission power.

[0172] Phase estimation module 533: Both communicating parties estimate the phase of the received signal.

[0173] The phase quantization module 534 quantizes the phase of the received signal into key bits according to the optimal quantization level.

[0174] Error negotiation module 541: The two communicating parties negotiate information to obtain the key bits with the smallest error.

[0175] The key generation module 542 removes leaked information through privacy amplification and generates a physical layer key.

[0176] Key usage module 543 uses physical layer keys for encrypted communication.

[0177] The implementation principle of the above steps can be found in the relevant introduction in the encryption method based on reconfigurable smart surfaces, and will not be repeated here.

[0178] This invention also provides an encryption device based on a reconfigurable smart surface, including a processor and a memory storing executable instructions for the processor. The processor is configured to execute steps of a reconfigurable smart surface-based encryption method via the executable instructions.

[0179] As shown above, the encryption system based on reconfigurable smart surfaces of this invention can maximize the key generation rate by introducing an active RIS (active reconfigurable smart surface) for physical layer key generation and increasing the channel gain to further improve the physical layer key generation rate while satisfying the total power constraint.

[0180] Those skilled in the art will understand that various aspects of the present invention can be implemented as systems, methods, or program products. Therefore, various aspects of the present invention can be specifically implemented in the following forms: a completely hardware implementation, a completely software implementation (including firmware, microcode, etc.), or a combination of hardware and software aspects, collectively referred to herein as a "circuit," "module," or "platform."

[0181] Figure 12 This is a schematic diagram of the encryption device based on a reconfigurable smart surface according to the present invention. See below for reference. Figure 12 An electronic device 600 according to this embodiment of the present invention is described. Figure 12 The electronic device 600 shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of the present invention.

[0182] like Figure 12 As shown, the electronic device 600 is presented in the form of a general-purpose computing device. The components of the electronic device 600 may include, but are not limited to: at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including storage unit 620 and processing unit 610), a display unit 640, etc.

[0183] The storage unit stores program code, which can be executed by the processing unit 610 to perform the steps described in the above-described section on the electronic prescription transfer processing method according to various exemplary embodiments of the present invention. For example, the processing unit 610 can perform actions such as... Figure 1 The steps are shown in the figure.

[0184] Storage unit 620 may include a readable medium in the form of a volatile storage unit, such as random access memory (RAM) 6201 and / or cache memory 6202, and may further include a read-only memory (ROM) 6203.

[0185] Storage unit 620 may also include a program / utility 6204 having a set (at least one) of program modules 6205, such program modules 6205 including but not limited to: processing system, one or more application programs, other program modules and program data, each or some combination of these examples may include an implementation of a network environment.

[0186] Bus 630 can represent one or more of several types of bus structures, including a memory cell bus or memory cell controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of the various bus structures.

[0187] Electronic device 600 can also communicate with one or more external devices 700 (e.g., keyboard, pointing device, Bluetooth device, etc.), and with one or more devices that enable a user to interact with electronic device 600, and / or with any device that enables electronic device 600 to communicate with one or more other computing devices (e.g., router, modem, etc.). This communication can be performed via input / output (I / O) interface 650. Furthermore, electronic device 600 can also communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public networks, such as the Internet) via network adapter 660. Network adapter 660 can communicate with other modules of electronic device 600 via bus 630. It should be understood that, although not shown in the figures, other hardware and / or software modules can be used in conjunction with electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms.

[0188] This invention also provides a computer-readable storage medium for storing a program that, when executed, implements the steps of an encryption method based on a reconfigurable smart surface. In some possible implementations, various aspects of the invention can also be implemented as a program product comprising program code that, when run on a terminal device, causes the terminal device to perform the steps described in the above-described electronic prescription processing method section of this specification according to various exemplary embodiments of the invention.

[0189] As shown above, the encryption system based on reconfigurable smart surfaces of this invention can maximize the key generation rate by introducing an active RIS (active reconfigurable smart surface) for physical layer key generation and increasing the channel gain to further improve the physical layer key generation rate while satisfying the total power constraint.

[0190] According to an embodiment of the present invention, a program product 800 for implementing the above-described method may employ a portable compact disc read-only memory (CD-ROM) and include program code, and may run on a terminal device, such as a personal computer. However, the program product of the present invention is not limited thereto. In this document, a readable storage medium may be any tangible medium containing or storing a program that may be used by or in conjunction with an instruction execution system, apparatus, or device.

[0191] The program product may employ any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of readable storage media include: electrical connections having one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0192] Computer-readable storage media may include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable storage medium may also be any readable medium other than a readable storage medium that can transmit, propagate, or transfer a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, RF, etc., or any suitable combination thereof.

[0193] Program code for performing the processing of this invention can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0194] In summary, the purpose of this invention is to provide an encryption method, system, device, and storage medium based on a reconfigurable smart surface, which can maximize the key generation rate while satisfying the total power constraint by introducing an active RIS (active reconfigurable smart surface) for physical layer key generation and increasing the channel gain to further improve the physical layer key generation rate.

[0195] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for encryption based on reconfigurable intelligent surface, characterized in that, The method comprises the following steps: obtaining channel state information between nodes of two parties in communication, wherein the nodes used by the two parties in communication comprise at least one active reconfigurable intelligent surface; obtaining an optimal parameter set under a maximum key generation rate state based on the channel state information; the two parties in communication mutually transmitting a same pilot signal according to the optimal parameter set, and quantizing a phase of a received signal into a key bit; and the two parties in communication performing information negotiation to determine to use the same key bit for encrypted communication.

2. The reconfigurable smart surface based encryption method of claim 1, wherein, The step of obtaining channel state information between nodes of two parties in communication, wherein the nodes used by the two parties in communication comprise at least one active reconfigurable intelligent surface, comprises: receiving a key generation request sent by the two parties in communication, wherein the nodes used by the two parties in communication comprise at least one active reconfigurable intelligent surface; obtaining channel state information between nodes.

3. The reconfigurable smart surface based encryption method of claim 1, wherein, The step of obtaining an optimal parameter set under a maximum key generation rate state based on the channel state information further comprises: when phases of all reflection channels of the active reconfigurable intelligent surface are aligned, a signal-to-noise ratio of a received signal is maximum and a key generation rate is maximum.

4. The reconfigurable smart surface based encryption method of claim 3, wherein, The step of obtaining an optimal parameter set under a maximum key generation rate state based on the channel state information comprises: obtaining an optimal reflection phase of the active reconfigurable intelligent surface when the signal-to-noise ratio of the received signal is maximum; obtaining an optimal reflection amplitude of the active reconfigurable intelligent surface when the signal-to-noise ratio of the received signal is maximum; obtaining an optimal transmission power of the active reconfigurable intelligent surface when the signal-to-noise ratio of the received signal is maximum; obtaining an optimal quantization order of the active reconfigurable intelligent surface when the signal-to-noise ratio of the received signal is maximum.

5. The reconfigurable smart surface based encryption method of claim 4, wherein, The step of obtaining an optimal reflection phase of the active reconfigurable intelligent surface when the signal-to-noise ratio of the received signal is maximum further comprises: the maximum key generation rate is positively correlated with the reflection amplitude of the active reconfigurable intelligent surface.

6. The reconfigurable smart surface based encryption method of claim 4, wherein, The step of the two parties in communication mutually transmitting a same pilot signal according to the optimal parameter set, and quantizing a phase of a received signal into a key bit comprises: adjusting a reflection coefficient of the active reconfigurable intelligent surface according to the optimal reflection phase and the optimal reflection amplitude; the two parties in communication mutually transmitting a pilot signal according to the optimal transmission power; estimating the phase of the received signal; quantizing the phase of the received signal into the key bit according to the optimal quantization order.

7. The reconfigurable smart surface based encryption method of claim 1, wherein, The step of the two parties in communication performing information negotiation to determine to use the same key bit for encrypted communication comprises: the two parties in communication performing information negotiation to obtain a key bit with a minimum error; generating a physical layer key by removing leaked information through privacy amplification; performing encrypted communication through the physical layer key.

8. A reconfigurable intelligent surface-based encryption system, characterized in that, The method comprises: a state collection module, which obtains channel state information between nodes of two parties in communication, wherein the nodes used by the two parties in communication comprise at least one active reconfigurable intelligent surface; an optimal parameter module, which obtains an optimal parameter set under a maximum key generation rate state based on the channel state information; a key bit module, which causes the two parties in communication to mutually transmit a same pilot signal according to the optimal parameter set, and quantizes a phase of a received signal into a key bit; and an encrypted communication module, which causes the two parties in communication to perform information negotiation to determine to use the same key bit for encrypted communication.

9. A reconfigurable smart surface based encryption device, characterized in that, Comprising: a processor; a memory having stored therein executable instructions of the processor; wherein the processor is configured to perform the steps of the method of any of claims 1-7 for reconfigurable smart surface based encryption via execution of the executable instructions.

10. A computer readable storage medium for storing a program, characterized in that, A program which when executed by a processor carries out the steps of the method of any of claims 1-7 for reconfigurable smart surface based encryption.

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