Physical layer authentication method based on mixed frequency hopping and channel phase response
By introducing hybrid frequency hopping and channel phase response methods in the physical layer authentication of wireless communication systems, the problem that existing systems are difficult to resist illegal access when facing attack strategies is solved, and higher authentication performance and anti-interference ability are achieved.
Patent Information
- Application Number
- CN202411724486.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-27
- Publication Date
- 2025-03-21
AI Technical Summary
When existing wireless communication systems face attack strategies such as simulated attacks and jamming attacks, they are difficult to effectively resist spoofing attacks such as illegal access and data tampering.
The physical layer authentication method based on hybrid frequency jump and channel phase response is adopted. By introducing frequency jump in the authentication process, the frequency jump mode is generated by nonlinear transformation based on the timestamp and shared key, ensuring the random change of carrier frequency and increasing anti-interference ability.
It improves the authentication performance under various attack strategies, enhances the anti-interference ability of the system, and enables legitimate users to maintain a high authentication success rate under jamming attacks.
Smart Images
Figure CN119676703A_ABST
Abstract
Description
Technical field:
[0001] The invention belongs to the technical field of wireless communications, and mainly relates to a physical layer authentication method based on mixed frequency hopping and channel phase response. Background technology:
[0002] Due to the openness of wireless media, it is common for illegal users to impersonate legitimate users to conduct illegal access, node cloning, data tampering and other deception attacks. As the underlying guardian of the communication system, wireless physical layer authentication (PLA) uses the unique attributes of the channel or device to identify attackers, providing the first line of protection for secure communications.
[0003] CN2021114639491 discloses a physical layer identity authentication method and system based on channel phase. The method utilizes the reciprocity of channel phase response of legitimate nodes to exchange information, hides the key information in the information interaction stage, and uses binary hypothesis test to complete the authentication in the final identity authentication. Meanwhile, the hypothesis test statistic is directly calculated by using the closed expression of the mean and variance of the hypothesis test statistic given in the method, which effectively improves the identity authentication performance and efficiency.
[0004] The above scheme uses a fixed carrier frequency through full authentication. In this process, Eve can easily detect the identity authentication and then use simulation attacks and jamming attacks. Jamming attacks can be easily launched through software defined radio (SDR), and the rapid development of jamming strategies, such as optimal jamming, reactive jamming, and intelligent jamming, has posed challenges to the anti-jamming strategies of real-world wireless networks. Summary of the invention:
[0005] In order to overcome the above-mentioned shortcomings, the present invention provides a physical layer authentication method based on hybrid frequency hopping and channel phase response.
[0006] The technical solution adopted by the present invention to solve its technical problem is:
[0007] A physical layer authentication method based on hybrid frequency hopping and channel phase response, comprising an authenticating end and an authenticated end, wherein the authenticated end and the authenticating end are both configured with the same shared key, and the authenticated end and the authenticating end both set the carrier frequency through a frequency hopping mode, the method comprising:
[0008] The authenticated end performs up-conversion on the authentication signal through a fixed carrier frequency and then sends it to the authenticating end; the authenticating end performs down-conversion on the received signal;
[0009] The authenticating end sends an authentication response signal to the authenticated end on the updated carrier frequency according to the frequency hopping mode;
[0010] After receiving the authentication response signal, the authenticated end generates a response signal according to the signal and its own frequency hopping pattern, and sends it to the authenticating end;
[0011] The authentication end calculates a test statistic after down-converting and low-pass filtering the response signal; finally, the test statistic variable is compared with a preset threshold value, thereby authenticating the identity of the authenticated end.
[0012] The frequency hopping pattern is generated according to a pseudo-random number n, which is calculated by TOD and a key using a nonlinear transformation; the pseudo-random number n is generated in the following steps:
[0013] Assume that the available frequency points are N h , we determine the carrier frequency f in each authentication process through FH n , where n = 1, 2, ... N h , so we can get
[0014] n=Mod(G(k A ,TOD),N h )+1
[0015] Among them, Mod and G(·) represent modular operation and nonlinear transformation respectively.
[0016] Due to the adoption of the above-mentioned technical solution, the present invention has the following advantages:
[0017] The present invention proposes a physical layer authentication method based on hybrid frequency hopping and channel phase response to improve the authentication performance under various attack strategies. The technical solution introduces frequency hopping (Frequency Hopping, FH) in the authentication process. The frequency hopping pattern is generated based on timestamp and shared key through nonlinear transformation to ensure that the carrier frequency used in each authentication process changes randomly. It is difficult for Eve to effectively perform interference attacks or passive attacks on the correct carrier frequency. In addition, considering that the time-varying characteristics of the wireless channel may not be well matched, especially for some quasi-static channels, FH can provide fast time-varying characteristics because the carrier frequency is updated in different authentication processes. The method increases the anti-interference ability of the system, so that legitimate users can still maintain a high authentication success rate under interference attacks. Description of the drawings:
[0018] Figure 1 It is a diagram of the authentication scheme model;
[0019] Figure 2 This is the identity authentication flow chart from Alice to Bob;
[0020] Figure 3 It is a comparison diagram of the detection probability of the present invention and the traditional channel phase-based PLA scheme under passive attack;
[0021] Figure 4 Comparison of detection probability between the proposed method and the traditional phase-based PLA scheme under mixed channel attack and constant interference at different signal-to-noise ratios
[0022] Figure 5 Comparison of detection probability between the proposed scheme and the traditional phase-based PLA scheme under mixed channel attack and constant interference at different JSRs Specific implementation method:
[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.
[0024] exist Figure 1 and 2 In , the authenticated end (legitimate user Alice) sends the authentication request to a public channel with a fixed carrier frequency, such as the kth frequency point. Here, the carrier frequency should be known to Alice and the attacker (Eve), because identity authentication is a public process for all possible users. Therefore, the up-converted authentication request signal is expressed as
[0025] x 1 =s R exp(2πf k t)
[0026] After the authentication end receives the authentication request signal, the authentication end (legal user Bob) will obtain the down-converted request signal. Then, Bob sends the authentication request to the user on the updated carrier frequency according to the FH mode. Inspired by FHSS, we generate the frequency hopping pattern based on the pseudo-random number n, which can be calculated by the timestamp (time of day, TOD) and the key using nonlinear transformation. Assume that the available frequency points are N h , we determine the carrier frequency f in each authentication process through FH n , where n = 1, 2, ... N h , so we can get
[0027] n=Mod(G(k A ,TOD),N h )+1
[0028] Where Mod and G(·) represent modular operation and nonlinear transformation respectively. The nonlinear transformation function G(·) is used to map TOD and shared key to a set of available frequency points, ensuring the randomness and diversity of frequency selection.
[0029] Alice calculates n according to the same process as Bob and determines the FH mode. Since Alice can obtain the same FH as Bob, Alice can receive the inquiry signal at the correct carrier frequency. Alice needs to receive the inquiry signal at the carrier frequency f n Send a response signal to Bob, expressed as:
[0030] x 2 =s A exp(2πf n t)
[0031] Eve will not attack the channel during the authentication request process for two reasons: First, since the channel is only used for authentication, continuously sending request signals or interference signals on the carrier frequency will be detected by Bob. Therefore, Bob may use anti-interference methods. Second, the start time of the legitimate authentication process is uncertain, so attacking the carrier frequency before the authentication process begins is inefficient.
[0032] Bob can receive the response signal of the carrier frequency, and after down-conversion and low-pass filtering, calculate the test statistic. Finally, Bob gets
[0033] The following is the performance analysis of the present invention:
[0034] Eve has two main attack categories: passive attacks and interference attacks. Based on these two attack categories, we consider two attack strategies of Eve, which may be used by Eve to threaten the authentication process in real scenarios.
[0035] 1) Passive attack only: In this strategy, we assume that Eve only tries to illegally pass the identity authentication by imitating Alice's behavior, which has been considered in the previous scheme. Specifically, in addition to using a forged key k E In addition, k E ≠k B , Eve starts the identity authentication process with the same steps as Alice,
[0036] 2) Mixed passive attack and constant jamming. In this strategy, Eve will transmit jamming signals to continuously attack the response signal. Specifically, when a legitimate authentication request is detected, Eve will send a jamming signal at the carrier frequency of the authentication request in an attempt to disrupt the response signal from Alice. J It can be expressed as:
[0037] ω J =ω EB
[0038] where ω EB The interference power is The noise modulated interference signal is When Alice does not send an authentication request, Eve will launch a passive attack and try to pass the authentication illegally.
[0039] The simulation experiments consider different signal-to-noise ratio (SNR) and interference-to-signal ratio (JSR) conditions, as well as different attack strategies. In the simulation, we utilize the channel phase-based PLA scheme as the baseline scheme. In addition, we consider two attack strategies of Eve, namely, using only passive attack, hybrid passive attack and continuous jamming attack, and hybrid passive attack and reactive jamming attack. We will study the authentication performance through the indicators of detection probability and ROC performance. In addition, we assume that Alice, Bob, and Eve are geographically located in a rich scattering environment. Without special instructions, we set the false alarm probability to p FA =0.01, the number of subcarriers N = 32, σ h =1, SNR = 10dB and N h =8. The average value is taken after 10^5 Monte Carlo times to display the simulation results.
[0040] A. Passive-aggression
[0041] exist Figure 3 , studied the comparison of detection probability under passive attack at different signal-to-noise ratios. Here, we determined the false alarm probability as p FA =0.01 to determine the threshold T. It can be observed that the present invention can significantly improve the detection probability. This is because FH makes it difficult for Eve to send a response signal at the correct carrier frequency. Therefore, the superior authentication performance of the present invention is verified.
[0042] B. Mixed passive attack and constant interference attack
[0043] exist Figure 4 In Figure 2, the detection probability comparison between the present invention and the traditional phase-based PLA scheme under different signal-to-noise ratios (SNRs) is shown for mixed passive attacks and constant interference. Here, JSR=10dB is set. It can be seen that the present invention improves the authentication performance because the effects of both passive attacks and constant interference can be eliminated by the FH gain. In addition, the theoretical curve and simulation curve of the detection probability are very consistent, which verifies the correctness of our performance analysis.
[0044] exist Figure 5In the figure, the detection probability comparison between the present invention and the traditional phase-based PLA scheme under mixed channel attack and constant interference at different interference-to-signal ratios (JSR) is shown. The signal-to-noise ratio is set to 10dB here, and T is calculated by fixing the false alarm probability. It can be found that the identity authentication performance of the system can be significantly improved by the present invention. Moreover, in the high SNR area, the performance improvement is significantly increased. This is because the FH gain is used in the present invention to effectively solve the impact of high JSR. Finally, the theoretical results of the detection probability are in good agreement with the simulation results, which proves the correctness of our performance analysis.
[0045] in conclusion:
[0046] Considering the various attack strategies that Eve may use during the PLA process, this paper proposes a new PLA method based on hybrid frequency hopping and channel phase. Specifically, FH is inserted in the channel phase-based PLA process to achieve FH gain, thereby improving the authentication performance.
[0047] In addition, we also conduct theoretical performance analysis on the present invention. The simulation results show that we can obtain better authentication performance under three attack strategies and prove the correctness of the theoretical results.
[0048] The parts not described in detail in the above content are prior art, so they are not described in detail.
Claims
1. A physical layer authentication method based on hybrid frequency hopping and channel phase response, characterized in that: The method comprises an authenticating end and an authenticated end, wherein the authenticated end and the authenticating end are both configured with the same shared key, and the authenticated end and the authenticating end both set the carrier frequency through a frequency hopping mode. The method comprises: The authenticated end performs up-conversion on the authentication signal through a fixed carrier frequency and then sends it to the authenticating end; the authenticating end performs down-conversion on the received signal; The authenticating end sends an authentication response signal to the authenticated end on the updated carrier frequency according to the frequency hopping mode; After receiving the authentication response signal, the authenticated end generates a response signal according to the signal and its own frequency hopping pattern, and sends it to the authenticating end; The authentication end calculates a test statistic after down-converting and low-pass filtering the response signal; finally, the test statistic variable is compared with a preset threshold value, thereby authenticating the identity of the authenticated end.
2. The physical layer authentication method based on hybrid frequency hopping and channel phase response according to claim 2, characterized in that: The frequency hopping pattern is generated according to a pseudo-random number n, which is calculated by TOD and a key using a nonlinear transformation; the pseudo-random number n is generated in the following steps: Assume that the available frequency points are N h , we determine the carrier frequency f in each authentication process through FH n , where n = 1, 2, ... N h , so we can get n=Mod(G(k A ,TOD),N h )+1 Among them, Mod and G(·) represent modular operation and nonlinear transformation respectively.