A Physical Layer Cooperative Group Key Generation Method Based on Joint Interference

Abstract

This invention relates to a physical layer cooperative group key generation method based on joint interference, belonging to the field of IoT security. It includes two stages: channel estimation and key negotiation. In the channel estimation stage, group users obtain their respective relay channel information, and relay nodes obtain superposition information about the reference channel and other relay channels. In the key negotiation stage, group users negotiate and generate a group key that is kept secret from the relay nodes using relevant observation information of the reference channel. This invention can achieve efficient and low-cost group key generation with high security, and is particularly suitable for star network scenarios such as UAV communication.

Description

Technical Field

[0001] This invention belongs to the field of Internet of Things (IoT) security and relates to a method for generating physical layer cooperative group keys based on joint interference. Background Technology

[0002] With the rapid development of IoT technology, wireless devices have become indispensable tools in people's daily work and life, enabling wider and faster information sharing and data transmission through wireless networks. However, with the widespread application of wireless devices, the security threats and risks they face are becoming increasingly prominent, which has become a key factor restricting their development. The security of traditional key encryption mechanisms mainly depends on the computational complexity of cracking the key algorithm, which is infeasible for many low-power, low-computing-capacity wireless terminals and devices (such as embedded sensors and wearable devices). To ensure the wireless communication security of these resource-constrained devices, research on lightweight physical layer key generation technology is of great significance.

[0003] Physical layer key generation (PLD) technology, based on information theory security, leverages the characteristics of wireless channels to achieve theoretical security independent of the eavesdropper's computational capabilities. Compared to traditional encryption techniques, PLD offers advantages such as low computational complexity and high theoretical security, making it a focus of current research and attention in the field of information security. However, most current research focuses on point-to-point key generation between two legitimate users. In many IoT applications, there is a need for information sharing and communication among multiple devices, making public key generation between IoT devices particularly important. For example, in smart home applications, it is necessary to share indoor environmental monitoring information with multiple automated home appliances, while also enabling group communication to support voice interaction, remote control, and other functions. Group communication is not a simple extension of point-to-point communication; key generation in multi-user networks is more complex and challenging.

[0004] Current group key generation research typically involves first generating paired keys among group users, and then using these paired keys for group key negotiation. However, this method incurs significant resource consumption. Therefore, researching efficient and low-cost physical layer group key generation for various IoT devices has become crucial and necessary. Furthermore, these wireless devices may not be within each other's communication range; this issue can be addressed using methods such as relay nodes (e.g.,...). Figure 2As shown in the diagram, the wireless device and the relay node together form a star network. However, as the central node of the star network, the relay node faces higher risks and threats, therefore it is necessary to ensure the confidentiality of the generated key to the relay node. A typical application scenario for star networks is drone communication, where each drone connects to a base station or control console. However, the base station or control console may be attacked or damaged, so it is also necessary to ensure the confidentiality of the transmitted data to the base station or control console.

[0005] In summary, in star networks, how to achieve efficient and low-cost group key generation while ensuring the confidentiality of the central node, and how to improve the group key rate, are problems that urgently need to be solved by technicians in this field. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a physical layer cooperative group key generation method based on joint interference for situations where there are information sharing and communication needs among multiple Internet of Things devices.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A physical layer cooperative group key generation method based on joint interference includes two stages: channel estimation and key negotiation. In the channel estimation stage, group users obtain their respective relay channel information, and relay nodes obtain superposition state information about the reference channel and other relay channels. In the key negotiation stage, group users use relevant observation information of the reference channel to negotiate and generate a group key that is kept secret from the relay nodes.

[0009] Furthermore, the group of users includes three legitimate users: Alice, Bob, and Carlo.

[0010] During the channel estimation phase, in time slot T1, the relay node Relay sends training sequence S1 to enable legitimate users Alice, Bob, and Carlo to obtain their respective estimates of the relay channel; in time slot T2, legitimate users Alice and Bob simultaneously send training sequence S2 to enable the relay node Relay to obtain superposition state information about relay channels h1 and h2; in time slot T3, legitimate users Alice and Carlo simultaneously send training sequence S3 to enable the relay node Relay to obtain superposition state information about relay channels h1 and h3.

[0011] During the key negotiation phase, the relay node Relay first uses its own observation information to generate auxiliary information to enhance the common information of legitimate users in the group; then, the legitimate user Alice uses the observation information of the reference channel h1 to generate auxiliary information so that the legitimate users in the group can negotiate and generate the group key.

[0012] Furthermore, in the channel estimation stage, during time slot T1, the relay node transmits a training sequence S1 so that legitimate users Alice, Bob, and Carlo obtain their respective estimates of the relay channel. Specifically, this includes: legitimate user Alice obtaining an estimate of h1. The legitimate user Bob obtains an estimate of h2. The legitimate user Carlo obtains an estimate of h3.

[0013]

[0014]

[0015]

[0016] Where h1, h2, and h3 represent the channel gain between Relay and legitimate users Alice, Bob, and Carlo, respectively; Y A Y B Y C These are the signals received by legitimate users Alice, Bob, and Carlo, respectively; N A N B , N C S1 is the additive white Gaussian noise at the locations of legitimate users Alice, Bob, and Carlo; S1 is the training sequence transmitted by the relay node Relay in time slot T1. T Represents the transpose of a vector or matrix.

[0017] Furthermore, during the channel estimation phase, in time slot T2, legitimate users Alice and Bob simultaneously transmit training sequence S2, enabling the relay node Relay to obtain superposition state information about relay channels h1 and h2. At this time, the relay node Relay obtains the estimated value.

[0018]

[0019] in, This refers to the signal received by the relay node Relay in time slot T2; S1 is the additive white Gaussian noise of the relay node Relay in time slot T2; S2 is the training sequence sent by legitimate users Alice and Bob in time slot T2.

[0020] Furthermore, during the channel estimation phase, in time slot T3, legitimate users Alice and Carlo simultaneously transmit training sequence S3, enabling the relay node Relay to obtain superposition state information about relay channels h1 and h3. At this time, the relay node Relay obtains the estimated value.

[0021]

[0022] in This refers to the signal received by the relay node Relay in time slot T3; S3 is the additive white Gaussian noise of the Relay in time slot T3; S3 is the training sequence sent by legitimate users Alice and Carlo in time slot T3.

[0023] Furthermore, during the key negotiation phase, the relay node (Relay) first uses its own channel estimate. Auxiliary information is generated and transmitted through a common channel, enabling legitimate users Alice, Bob, and Carlo to obtain relevant observations about the reference channel h1. Then the legitimate user Alice uses Slepian-Wolf encoding to exploit... Auxiliary information is sent and transmitted over a public channel, enabling legitimate users Alice, Bob, and Carlo to negotiate and generate a group key.

[0024] The beneficial effects of this invention are as follows: This invention can achieve efficient and low-cost group key generation and has high security, making it particularly suitable for star network scenarios such as drone communication.

[0025] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0026] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0027] Figure 1 Flowchart for generating group keys;

[0028] Figure 2 This is an N-node system model;

[0029] Figure 3 It is a three-node system model;

[0030] Figure 4 A time slot allocation diagram for sending training sequences to each node;

[0031] Figure 5 The curve shows the key rate as a function of the signal-to-noise ratio.

[0032] Figure 6This relates the key rate to the number of users in the group. Detailed Implementation

[0033] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0034] The model considered in this invention is as follows Figure 2 As shown, the model considers a star network, which includes N (N≥3) legal nodes U1, U2, ..., U3. N The group consists of one relay node (Relay) and one eavesdropping node (Eve), all equipped with a single antenna. There are no direct links between group users (i.e., they are not within each other's communication range), and they can only communicate via the Relay. To ensure the security of group communication, the N group users need to generate a group key in the presence of Eve. It is assumed that there is a noise-free public channel between the nodes; Eve can also access the public channel through which legitimate nodes exchange information. Furthermore, the eavesdropping node Eve is a passive node and will not send signals to interfere with legitimate transmissions. It is assumed that Eve is at least half a wavelength away from legitimate users, which ensures that the observations of the eavesdropping node and the legitimate nodes are independent of each other.

[0035] Let h 1,R h represents the channel gain from node U1 to the Relay. R,1 Given the channel gain from Relay to node U1, h can be obtained based on channel reciprocity. 1,R =h R,1 =h1; Similarly, node U i The channel gain between the relay and the channel can be expressed as h. i (i = 1, 2, N). The wireless channel is modeled as a time-varying Rayleigh block fading channel, meaning the channel gain remains constant within the coherence time T and changes to other independent random values ​​in the next coherence time. It is assumed that the noise received by all nodes is independent and identically distributed zero-mean circularly-symmetric complex Gaussian (ZMCSCG) white noise with variance... Channel gain h i (i = 1, 2, N) is a group with variance of The ZMCSCG random variable, i.e.

[0036] by Figure 3 Taking the three-node system model shown as an example, the key generation process of this invention consists of two steps: the first step is channel estimation, and the second step is key negotiation. The physical layer group key generation flowchart is shown below. Figure 1 As shown, the detailed process is as follows:

[0037] I. Channel Estimation

[0038] This step consists of three time slots, allocating the coherence time T into three time slots T1, T2, and T3, i.e., T = T1 + T2 + T3, as shown in the time slot allocation. Figure 4 As shown. In this embodiment, three legitimate nodes are used as an example. It is assumed that the transmission power of legitimate nodes Alice, Bob, and Carlo, and the relay node Relay, is all P. Therefore, ||S1|| 2 =PT1, ||S2|| 2 =PT2, ||S3|| 2 =PT3.

[0039] 1. In time slot T1, Relay sends the same training sequence S1 to Alice, Bob, and Carlo. Alice, Bob, and Carlo receive signals Y respectively. A =h1S1+N A Y B =h2S1+N B and Y C =h3S1+N C At this point, Alice can obtain an estimate of h1. Bob can obtain an estimate of h2. Carlo can obtain an estimate of h3.

[0040]

[0041]

[0042]

[0043] 2. In time slot T2, Alice and Bob simultaneously send the same training sequence S2 to the Relay. The Relay receives the superposition state information of relay channels h1 and h2. At this point, Relay can obtain an estimated value.

[0044]

[0045] 3. In time slot T3, Alice and Carlo simultaneously send the same training sequence S3 to the Relay. The Relay receives the superposition state information of relay channels h1 and h3. At this point, Relay can obtain an estimated value.

[0046]

[0047] Therefore, we can obtain All are ZMCSCG variables, and

[0048] II. Key Negotiation

[0049] After the channel estimation phase, Alice, Bob, and Carlo still lack common randomness. Therefore, Relay needs to send auxiliary information to enable Alice, Bob, and Carlo to obtain relevant observations about channel h1. Since Relay possesses joint observation information about channels h1 and h2, as well as h1 and h3... Therefore, it will estimate Quantized into binary sequence Where Δ represents the quantization interval; then the quantized... (Right now The signal is sent to Alice, Bob, and Carlo via a common channel. Because a noise-free common channel is considered, Alice, Bob, and Carlo can receive it accurately. If we let the quantization interval Δ approach 0, then Alice, Bob, and Carlo can obtain... At this point, Bob combines his own channel estimation values. and information obtained through public channels Obtain an estimate of channel h1. Carlo combines its own channel estimates and information obtained through public channels Obtain an estimate of channel h1. Therefore, the three legitimate users obtained relevant observations about channel h1. This related observation can be used to generate group keys.

[0050] because Given the estimated channel h1 for different received noise levels, key negotiation is required to enable legitimate users to negotiate and generate a key at a rate of R. G Group key K G Alice uses Slepian-Wolf coding, first estimating its own information about channel h1. Quantized into binary sequence Bob and Carlo also quantized their respective observations into binary sequences. and Then Alice randomly... The typical set of sequences is divided into non-overlapping subsets, each subset containing multiple sequences. Typical sequences are generated, each containing two indices: the index of the subset it belongs to and the sequence index within the subset. Alice then uses the sequence index within the subset as the key K. G Then, the subset index number is sent as auxiliary information to Bob and Carlo via the public channel. Alice needs to send it via the public channel. By combining their own relevant observations with information transmitted over public channels, Bob and Carlo can accurately recover the bit information.

[0051] Because the subset index number and the sequence index number within the subset are independent of each other, even if Eve obtains the subset index number, she still doesn't know the sequence index number within the subset, meaning she cannot obtain any information about the key. Furthermore, Relay has already... Transmitted through a common channel, therefore This should be considered public information to ensure the security of the group key K. G Security. By making the quantization interval Δ approach 0, the key rate can reach R. G ,Right now

[0052]

[0053] Note that the generated group key K G The key is kept secret from the relay node, thus providing a high level of security.

[0054] Experimental Verification: The method of this invention was verified using the Matlab simulation platform. For ease of analysis, it was assumed that the time occupied by each time slot was T1 = T2 = T N =5, the variance of the relay channel gain is 5. noise variance

[0055] Figure 5 The simulation shown is a curve illustrating the change in key rate as a function of signal-to-noise ratio (SNR). As can be seen from the curve, the key rate of the key generation method proposed in this invention increases with increasing SNR.

[0056] Figure 6The simulation shown illustrates the relationship between key rate and the number of group users. As can be seen from the figure, the key rate decreases with increasing group users. This is because an increase in the number of group users leads to a greater required coherence time T, and noise superposition reduces the number of relevant observations from group users.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A physical layer cooperative group key generation method based on joint interference, characterized in that: It includes two stages: channel estimation and key negotiation. In the channel estimation stage, group users obtain their respective relay channel gain information, and relay nodes obtain superposition state information about the reference channel and other relay channel gains. During the key negotiation phase, group users negotiate and generate a group key that is kept secret from the relay node using relevant observation information of the reference channel. The group of users includes three legitimate users: Alice, Bob, and Carlo. In the channel estimation stage, In the time slot, the relay node (Relay) sends the training sequence. This allows legitimate users Alice, Bob, and Carlo to obtain their respective estimates of the relay channel gain; During the time slot, legitimate users Alice and Bob simultaneously send training sequences. Enables the relay node (Relay) to obtain information about the relay channel gain. and Superposition state information; in During the time slot, legitimate users Alice and Carlo simultaneously send training sequences. Enables the relay node (Relay) to obtain information about the relay channel gain. and Superposition state information; During the key negotiation phase, the relay node Relay first uses its own observation information to generate auxiliary information to enhance the common information of legitimate users within the group; legitimate user Alice reuses the reference channel The observation information generates auxiliary information to enable legitimate users within the group to negotiate and generate a group key; In the channel estimation stage, In the time slot, the relay node (Relay) sends the training sequence. This allows legitimate users Alice, Bob, and Carlo to obtain their respective estimates of the relay channel gain. Specifically, this includes: legitimate user Alice obtaining... The estimated value The legitimate user Bob receives the right to... The estimated value The legitimate user Carlo received the right to The estimated value : in , , These represent the channel gain between Relay and legitimate users Alice, Bob, and Carlo, respectively. , , These are the signals received by legitimate users Alice, Bob, and Carlo, respectively. , , Additive white Gaussian noise at the locations of legitimate users Alice, Bob, and Carlo; For the relay node Relay Training sequences transmitted in time slots Represents the transpose of a vector or matrix; In the channel estimation stage, During the time slot, legitimate users Alice and Bob simultaneously send training sequences. Enables the relay node (Relay) to obtain information about the relay channel gain. and The superposition state information allows the relay node (Relay) to obtain an estimated value. : in, For the relay node Relay Signals received in the time slot; for Additive white Gaussian noise in relay nodes under time slots; For legitimate users Alice and Bob Training sequences transmitted in time slots; In the channel estimation stage, During the time slot, legitimate users Alice and Carlo simultaneously send training sequences. Enables the relay node (Relay) to obtain information about the relay channel gain. and The superposition state information allows the relay node (Relay) to obtain an estimated value. : in For the relay node Relay Signals received in the time slot; for Additive white Gaussian noise in the relay under time slots; For legitimate users Alice and Carlo in Training sequences transmitted in time slots.

2. The physical layer cooperative group key generation method based on joint interference according to claim 1, characterized in that: During the key negotiation phase, the relay node Relay first uses its own channel estimate. Auxiliary information is generated and transmitted through a public channel, enabling legitimate users Alice, Bob, and Carlo to obtain information about the reference channel. Related observations Then, the legitimate user Alice uses Slepian-Wolf encoding to exploit... Auxiliary information is sent and transmitted over a public channel, enabling legitimate users Alice, Bob, and Carlo to negotiate and generate a group key.

Images