130 results about "Covert communication" patented technology

The invention discloses an encrypted communication system and method based on cognitive multi-carrier spread spectrum, and belongs to the field of covert communication. The encryption communication system comprises a transmitting device and a receiving device. The transmitting device comprises a data encryption module, a constellation encryption modulation module, a multi-carrier spread spectrum module, a frequency hopping module and a cognitive power distribution module. The receiving device comprises a band-pass filtering module, a de-hopping frequency module, a de-spreading module, a constellation decryption demodulation module, a data decryption module and a coherent combination module. The data encryption module is divided into an interleaving coding unit and a double-rule reversible cellular automaton encryption unit. The cognitive power distribution module continuously scans a wireless electromagnetic environment and carries out real-time spectrum analysis to give power spectrum density results sensed under all frequency hopping frequency sets. According to the invention, continuous detection and dynamic response to the spatial frequency spectrum state can be realized, and the communication concealment, the anti-interference performance and the resource utilization efficiency in a complex electromagnetic environment are remarkably improved by utilizing the frequency spectrum hole.

The invention discloses a covert communication optimization method based on deep reinforcement learning under limited character input, and belongs to the technical field of wireless communication. According to the method, an optimization problem which takes the minimum average bit error rate as a target function and takes hidden requirements, power and the like as constraints is constructed on a hidden communication model of a transmitting end, a receiving end, an intelligent reflecting surface and a monitor. Firstly, the bit error rate of a receiving end is given, the detection performance of a monitor is analyzed, and the KL divergence upper bound and the corresponding hidden constraint are deduced. The objective function and the constraint set of the constructed problem are non-convex, the optimization problem is trained and solved by constructing the optimization problem into a deep reinforcement learning model, the modulation order which is difficult to optimize by a traditional algorithm is optimized by using the advantages of deep reinforcement learning, a deep deterministic strategy gradient algorithm is selected to train the model, and then the error rate is minimized. And the covert communication performance is improved.

The invention provides an unmanned aerial vehicle covert communication method and system supported by a movable antenna, and the method comprises the steps: calculating the maximum communication rate of a legal user under the support of the movable antenna according to a communication scene of the movable antenna; according to a movable antenna communication scene, calculating a minimum detection error rate under multi-illegal-guard cooperative detection; based on the maximum communication rate and the minimum detection error rate, a joint optimization problem of time slot segmentation, beam forming, unmanned aerial vehicle trajectory and movable antenna position is established, and the optimization objective is to maximize the minimum throughput of legal users under the condition of satisfying covert communication constraints; an iterative algorithm based on block coordinate descent and continuous convex approximation is adopted to obtain optimized time slot segmentation, beam forming, unmanned aerial vehicle trajectory and movable antenna position parameters, and the parameters are applied to covert communication of the unmanned aerial vehicle. According to the method provided by the invention, the concealment requirement of unmanned aerial vehicle communication can be well met, and the network security is improved.

The invention discloses a covert communication system based on a generative diffusion model, and belongs to the technical field of covert communication. In order to solve the problems of insufficient concealment and poor anti-noise performance in the prior art, hidden transmission and reliable recovery of information are realized by constructing a diffusion generation and classification discrimination module. The sending end carries out noise addition and shaping on the original bit waveform by using a forward diffusion process to form a noise-like hidden signal; and a receiving end recovers a signal structure through a reverse denoising process, and accurately judges bit information through a classifier. According to the method, a Gaussian approximation hidden waveform library is constructed by adopting a signal pair training model which is consistent in statistics but distinguishable in structure, and random sampling mapping and boundary smooth splicing are combined, so that transmission signals are difficult to distinguish from noise in a frequency domain and a feature space; therefore, the avoidance capability, the anti-interference robustness and the information recovery accuracy under the low signal-to-noise ratio of the detection means are remarkably improved.

The invention discloses an unmanned aerial vehicle ISAC system beam and three-dimensional trajectory joint optimization method for covert communication. Aiming at the condition that potential monitors exist in a network architecture in which an unmanned aerial vehicle performs downlink information transmission to a plurality of ground users, a communication system model is firstly constructed, and then an optimization problem conforming to a scene with user scheduling, a communication and sensing integrated waveform and an unmanned aerial vehicle flight path as constraints is constructed by taking maximization of an average covert communication rate of a system as a target; then, based on a BCD method, an original optimization problem is decoupled into sub-problems about user scheduling, a common inductance integrated waveform and a UAV three-dimensional flight path, and convex approximate fitting is carried out on each non-convex sub-problem; and finally, solving by adopting an iterative algorithm to find a global suboptimal solution of the whole optimization problem, an optimal sensing integrated waveform and a UAV flight trajectory. According to the invention, the security of information transmission is improved, the communication quality and concealment are maximized, and concealed transmission of information is realized.

The invention provides a hierarchical medical scene-oriented dynamic interference cooperative communication optimization system and method, and relates to the technical field of medical data communication security. The hierarchical medical scene-oriented dynamic interference cooperative communication optimization method comprises the following steps: S1, based on hierarchical medical scene differences of emergency treatment, ICU and common wards, realizing covert communication by using native physiological data transmission mutual interference signals of multiple devices in a medical monitoring network; s2, different communication security thresholds and data timeliness indexes are set for different levels of scenes; and S3, constructing a dynamic interference coordination framework, and realizing interference intensity adaptation by adjusting the transmission power (Pi) of the medical equipment and the dedicated channel gain (hj, iva). According to the invention, through linkage with the HIS system, differentiated safety thresholds and timeliness indexes are set for emergency treatment, ICU and common wards, and priority requirements of different scenes are accurately met; parameter synchronization can be rapidly completed during cross-scene transfer, and the problem of connection lag of a traditional scheme is solved.

The invention relates to the technical field of low-power wide area network communication and information hiding, and discloses a LoRa-based covert communication method, which comprises the following steps of: at a transmitting end, generating a key-driven perturbation sequence according to covert information to be transmitted, constraining perturbation parameters through an undetectable controller, and transmitting the perturbation sequence to a receiving end; performing symbol-level perturbation modulation on the linear frequency modulation slope of the LoRa signal, and embedding a low-speed synchronous beacon in a preamble symbol counting tolerance range; at a receiving end, conventional data is demodulated through a standard LoRa receiving process, a frequency offset residual error, a phase residual error and a symbol fitting error after de-spreading are extracted in parallel, related detection is carried out by using a key consistent with a sending end, and hidden information is extracted from a residual error domain; the undetectability controller dynamically adjusts perturbation magnitude and embedding density based on a distribution difference metric. The objective of the invention is to solve the problem that communication reliability and hidden undetectability are difficult to guarantee at the same time in a LoRa system.

The invention relates to the technical field of covert communication, in particular to a bionic covert communication method based on multi-sea-area dolphin voiceprint feature library matching, which comprises the following steps of: constructing a dynamic voiceprint feature library associated with sea area coordinates, dolphin species and voiceprints, and adjusting acoustic parameters in combination with real-time environment monitoring; communication information is encoded in a natural variation range of acoustic characteristics of the dolphin, bionic signals highly conforming to the sound scene of a target sea area are synthesized and emitted, low-recognizable and low-monitorable hidden data transmission between underwater equipment is achieved, meanwhile, false alarm of a marine mammal protection system is avoided, and the safety communication requirement of equipment such as an unmanned underwater vehicle is met.

The invention discloses a signal depth detection method, a signal depth detection device, signal depth detection equipment and a medium for a low interception waveform, and relates to the technical field of signal identification. According to the method, the covert communication signal can be effectively detected without using signal energy and periodic characteristics, so that the use of the signal energy and the periodic characteristics of the frequency domain is avoided, and the covert communication signal of variable parameter spread frequency hopping can be effectively detected under the condition of low signal-to-noise ratio.

The embodiment of the invention provides a steerable antenna-based covert communication system transmission rate enhancement method and related equipment, and belongs to the technical field of wireless communication. The method comprises the following steps: introducing an antenna pointing vector and a deflection angle pair to represent the three-dimensional direction of a single steerable antenna, establishing a channel model related to the antenna deflection angle pair, and deducing a hidden rate expression of a legal user; deducing a hidden constraint condition expression of the illegal user side by using the channel model; according to the concealment rate expression and the concealment constraint condition expression, constructing a joint optimization problem taking maximization of the concealment rate of the legal user as a target and taking concealment constraint, transmitting power constraint and antenna steering angle constraint as conditions; and solving the joint optimization problem to obtain an optimized transmitting beam forming vector and a deflection angle pair of the steerable antenna. The antenna orientation is dynamically adjusted, the spatial degree of freedom is fully excavated, and the transmission rate of the system can be remarkably improved on the premise of strictly ensuring the communication concealment.

This application discloses an intelligent reflective surface and a covert communication system, belonging to the field of wireless communication technology. The intelligent reflective surface includes multiple intelligent reflective surface units arranged in an array; each intelligent reflective surface unit includes: a first substrate, a second substrate, and a third substrate; a metal patch and a varactor diode, located on the side of the third substrate opposite to the second substrate; the metal patch includes a first patch and a second patch, and the varactor diode is located between the first patch and the second patch, with its negative and positive terminals electrically connected to the first patch and the second patch, respectively; a metal ground plane, located between the first substrate and the second substrate; a first bias line and a second bias line, located on the side of the first substrate opposite to the second substrate; the first bias line is electrically connected to the metal ground plane and the first patch, respectively, and the second bias line is electrically connected to the second patch. This application can achieve precise control of electromagnetic waves, reduce electromagnetic energy loss, improve energy transmission efficiency, suppress electromagnetic wave leakage, and improve communication covertness.

This application provides a method and apparatus for detecting covert communication behavior, relating to the field of network security technology. On one hand, the method uses a dynamic time warping algorithm to determine the minimum cumulative distance between the packet length-timestamp sequence and the standard response traffic template sequence in the packet length dimension. This quantifies temporal misalignment differences, thus solving the problem of missed detection caused by the lack of temporal analysis capabilities in traditional methods. On the other hand, based on the arrival timestamp of the packet length-timestamp sequence, the method determines the differential entropy and the maximum time span of sudden events. The differential entropy can amplify the minute temporal fluctuations caused by the mechanical packet sending of tunnel traffic, while the maximum time span can identify deliberately lengthened idle periods in tunnel traffic. Combining these two methods can accurately capture gradual covert communication such as slow tunnels. Therefore, this method can improve the accuracy of detecting covert communication behavior.

A multi-party password book distribution method based on secret sharing, a sender uploads a password book to an interstellar file system through public key encryption, adopts secret sharing to secret split information obtained by splicing a public key and a Hash of an expected receiver, a receiver obtains a secret share through biological feature recognition technology, and obtains a sender public key through a judgment function to download an original password book from the interstellar file system. According to experimental results and security analysis, the scheme can guarantee high time efficiency and resist impersonation attacks, and guarantee the safe transmission of the password book. The present application solves the security problem of password book distribution by adopting a shamir threshold scheme, changes the threshold for safe password book distribution, dynamically solves the entry and exit of receivers, solves the problem that original covert communication can only perform one-to-one communication, and realizes one-to-many communication.

The invention discloses a covert communication method based on a simultaneous transmission and reflection reconfigurable intelligent surface, and the method comprises the following steps: in a system, a base station sends an NOMA signal to a first communication user through a direct connection link and an ASTAR-RIS reflection link, and sends a signal to a second communication user through an ASTAR-RIS transmission link, the first communication user is used as an energy collection node to perform energy collection and signal decoding by using the SWIPT technology; and when the second communication user fails to decode successfully, the first communication user forwards a signal of the second communication user by using the collected energy, and the second communication user sends interference to the monitor at the same time to weaken the detection performance of the monitor. According to the method, ASTAR-RIS, NOMA and SWIPT technologies are combined, the communication spectrum efficiency and the energy utilization rate can be improved, meanwhile, the detection performance of a monitor is effectively reduced, and the reliability and the practical value of a covert communication system are improved.

The application discloses a method for realizing covert communication by using a terahertz high-speed data transmission, which combines information hiding technology with a terahertz high-speed data transmission system, uses original data of a terahertz high-speed data transmission channel as a carrier, carries out digital sampling on an analog signal which needs to be separately transmitted, modifies values of a data part of the carrier, matches the data to be hidden with a function value of the carrier data, hides marking information in the data containing the hidden information, and further improves quality of the carrier data at a receiving end, and saves channel resources for transmitting the analog signal. The information hiding process is carried out at a front end of the terahertz high-speed data transmission system, and does not change a terahertz wireless communication system. The hiding method is simple and flexible, and PSNR is improved by 3 dB compared with a least significant bit replacement method under the condition of the same hiding capacity.

The application discloses a UAV dynamic spectrum sensing and covert communication method suitable for resisting environment, and relates to the technical field of UAV communication; the application extracts a sensing quality index and an interference influence index based on initial interference signal characteristics, calculates a UAV single-machine fusion weight by combining an entropy weight method, dynamically weights and fuses single-machine sensing data of each UAV, and can further introduce an interference suppression factor to generate interference-spectrum double-feature fusion features to extract single-machine sensing data; the application can adaptively distribute fusion weights according to interference levels and sensing accuracy, avoids fusion errors caused by strong interference UAVs, fully develops the advantages of airspace diversity of multiple machines, significantly improves spectrum sensing accuracy and robustness, reduces multiple-machine data redundancy, and improves sensing real-time performance.

The invention relates to a high-security hidden communication system, and belongs to the technical field of information security. According to the system, the mark feature and the structural feature of encrypted data are eliminated through a strong encryption technology, the key feature of the encrypted data is eliminated, the key security is ensured, the ciphertext security is improved, and the risk problem brought by side channel analysis to the data encryption security is solved; a double-layer covert channel is realized through a multimedia steganography technology and a flow simulation technology, the concealment of communication behaviors is greatly enhanced, and the problem of insufficient concealment of a single-layer covert channel is solved; the hidden communication technology with both concealment and anonymity is realized by combining the hidden channel with the anonymous network, and the problems that the anonymous network has obvious traffic characteristics and network boundary nodes are easy to expose are solved.

The invention discloses a multi-user hidden networking method based on double time scale constraints. The method comprises the following steps: 1, slicing time-frequency network resources to obtain an available time-frequency slot set; 2, obtaining a basic random sequence M < k > under the action of a system clock and a user authentication key; 3, performing cyclic shift transformation on the basic random sequence M < k > to obtain an extended sequence family NL * K; step 4, carrying out orthogonalization processing on the extended sequence family NL * K to obtain a decision sequence family HL * K, and guiding multiple users to access the network; 5, authorized user access protocol performance analysis is carried out, and dual-time-scale constraint is carried out to achieve the optimal networking throughput; step 6, reliability and security analysis is carried out on the covert communication system; and 7, analyzing the tolerance of the covert communication system, and solving by using an improved SA-PSO algorithm. According to the method, multiple users are guided to asynchronously access the covert communication network through dynamic management and allocation of spectrum resources, and the method has the characteristics of high efficiency, flexibility, stability and accuracy.

The application discloses a kind of based on affine frequency division multiplexing covert communication method and system.The method includes: transmitting end and receiving end respectively carry out channel estimation, obtain channel state information, and construct frequency domain channel matrix;Using channel reciprocity, both sides independently generate the same Chirp parameter codebook, avoid eavesdropper reconstruction;Transmitting end generates corresponding modulation symbol according to the input modulation bit;According to the amplitude of the diagonal element of frequency domain channel matrix, index bit is selected to the starting position of the Chirp parameter codebook;Transmitting end carries out affine frequency division multiplexing modulation according to the Chirp parameter codebook selected by index bit to constellation symbol and transmits;Receiving end reconstructs Chirp parameter codebook using its own CSI and completes matching decoding and modulation decryption.The application realizes shared password book without the need of privacy information exchange, makes full use of waveform parameter degree of freedom, improves the spectral efficiency and communication security of system, and is suitable for high-speed mobile communication data covert transmission.

The application discloses a kind of transmission power optimization methods, products and equipment for multi-cooperative monitoring underwater acoustic covert communication, comprising: estimating when sending node sends preset symbol, each listening node listens to the received signal, according to received signal, the transmission power observed by each listening node is calculated, and then the decision statistics of each listening node is calculated;Select the fusion strategy corresponding to the underwater acoustic covert communication environment where it is located, fuse the decision statistics of each listening node to obtain joint decision statistics;Determine whether joint decision statistics meet preset condition, if yes, establish transmission power optimization model, the joint false alarm rate of multiple listening nodes cooperative monitoring is lowest as the goal of transmission power optimization model, with total communication throughput greater than or equal to preset threshold as constraint condition, transmission power is disturbed in each communication time slot Control;The optimal transmission power is obtained by solving.This application is applicable to underwater acoustic covert communication scene with multiple listening nodes.

The application belongs to the technical field of unmanned aerial vehicle communication sensing, and specifically discloses a method for jointly scheduling communication and sensing resources of an unmanned aerial vehicle in a covert communication scenario, which comprises the following steps: establishing a communication performance model and a radar sensing performance model; combining covert communication constraints and no-fly zone avoidance constraints to build a joint optimization problem of communication and sensing resources; solving the closed-form optimal solution of sensing power and communication power, and reducing variables of the joint optimization problem; introducing a segmented hovering flight structure to discretize the continuous flight trajectory of the unmanned aerial vehicle, and combining the closed-form optimal solution to convert the joint optimization problem into a discrete optimization problem; using a block coordinate descent algorithm to alternately and iteratively solve the discrete optimization problem, and outputting an optimal user association strategy, an unmanned aerial vehicle hovering time and a continuous flight trajectory of the unmanned aerial vehicle. The application can improve the covert communication capability and comprehensive sensing accuracy of the unmanned aerial vehicle under the premise of meeting the covert communication demand and physical no-fly zone constraints.

The present application relates to a kind of industrial equipment electromagnetic radiation covert communication detection data processing method, belong to communication data processing technical field.The method is first compared with the similarity of each environmental data variation and noise variation, determine the relative influence weight of each environmental data to noise, then based on the electromagnetic intensity value of recent data determines the stable change period in recent data, with environmental data under stable change period as reference, compare the deviation of current time environmental data with reference and determine adjustment factor in combination with relative influence weight, determine the adaptive detection reference suitable for current detection according to adjustment factor, effectively eliminate the influence of noise variation on electromagnetic intensity signal detection quantity due to the fluctuation of current environmental state relative to recent stable state, by improving electromagnetic radiation data processing method, provide basis reference for more accurate detection of covert communication in industrial scene.

The invention relates to the technical field of covert communication and network security, in particular to an under-chain covert communication method and system based on blockchain network messages, and the method comprises the steps: building a dual-message covert communication model; designing a coding strategy; carrying out concealment processing; designing a decoding strategy; according to the method, the problems of high cost and easy information exposure of an on-chain covert communication method based on a block chain are solved, low-cost, high-concealment and high-bandwidth covert communication is realized, and the method has a wide application prospect.

This invention discloses a generative acoustic scene underwater covert communication method based on message latent variable injection, comprising: acquiring a message to be sent and acoustic scene condition information of a target local sea area; inputting the message to be sent into a trained message encoding module for encoding processing to obtain message latent variables; injecting the message latent variables into a trained condition generation module so that the condition generation module generates an acoustic scene underwater acoustic payload waveform carrying the message to be sent under the constraints of the acoustic scene condition information; processing the acoustic scene underwater acoustic payload waveform to obtain a covert communication frame suitable for transmission, and transmitting the covert communication frame; thereby, by simultaneously realizing acoustic scene camouflage and message carrying during the generation of the acoustic scene underwater acoustic signal, underwater covert communication that balances the acoustic scene adaptability of the target local sea area, the low distinguishability of the generated signal, and the reliability of legitimate reception recovery after underwater acoustic propagation is achieved.

The application discloses a kind of concealed communication detection methods based on federal learning, including the following steps: the sample data transmitted by several time slots antennas is stored in the form of matrix;Determine global model, center server initializes global model;Center server distributes initialized global model to user;Participating node downloads global model from center server, and uses local data to train and update local model with downloaded global model as local model;Participating node uploads local model to center server, and center server receives all local models and carries out model aggregation update, forms new global model;Center server distributes new global model to all training nodes, and carries out iterative training;User detects local data with the final updated global model, judges whether concealed communication data is contained in physical layer signal, and completes classification detection task.The application saves communication resources and protects data security.

This invention relates to a covert communication method based on block parameter uncertainty, belonging to the field of wireless communication technology. The method includes: constructing a covert communication model in a multi-user dynamic access scenario and deriving covert communication judgment rules for eavesdroppers; based on the covert communication judgment rules, analyzing the general conditions for covert communication parties to evade hypothesis testing; and based on the general conditions for covert communication parties to evade hypothesis testing, introducing an equivalent power variance under the condition that the interference source uses a pulse-shaping transmission strategy to obtain the optimal transmission power. This invention addresses covert communication scenarios where interference sources exist. Combining block parameter uncertainty, it utilizes the general covert conditions of intersecting manifold spaces and employs a roll-off coefficient to construct an equivalent power model for pulse shaping, achieving the optimal covert communication power for the transmitter.

The application discloses a decision fusion method and system in a multi-listening scenario in covert communication and belongs to the technical field of wireless communication. The method comprises the following steps: configuring a limited total block length for each listening node, and dividing the total block length into a detection block length and a transmission block length; each listening node performs local signal sensing, generates a local decision result by using the detection block length, and sends the local decision result to a fusion center by using the transmission block length; the fusion center allocates an optimal fusion weight for each decision result based on the local detection performance and the transmission performance of each listening node according to the criterion of minimizing the global detection error probability; the fusion center calculates a weighted sum based on the fusion weight and the corresponding decision result, compares the weighted sum with an optimal decision threshold of the fusion center, and makes a global decision on whether the target signal exists. The application realizes the optimal performance of a whole link from sensing to fusion, and improves the reliability and accuracy of signal detection.

The application claims a kind of unmanned aerial vehicle assisted short packet covert communication method based on ground node cooperative interference, the theoretical lower bound of detection error probability is deduced, and then the exact robust concealment constraint condition is built.In terms of system optimization, the highly coupled non-convex objective problem is decomposed, and a joint optimization scheme of unmanned aerial vehicle transmission power, interference beam forming, multi-user scheduling decision and flight trajectory is designed to ensure the balance between covert communication and multi-user resource allocation fairness.Meanwhile, by integrating continuous convex approximation and semi-positive relaxation technology, combined with generalized Benders decomposition algorithm, effective decoupling of discrete decision variables and continuous physical variables is realized, and an alternating optimization solution strategy with strict theoretical convergence guarantee is proposed.Numerical simulation and theoretical analysis results show that the application significantly outperforms existing benchmark schemes in improving the average transmission rate of the worst user, with significant superiority.

We disclose a novel methodology and wireless network for covert wireless RF communications between an agent device and a client device in the presence of an adversary device which attempts to detect the existence of the transmission of the RF communication between the agent and client. The methodology comprises: providing an intelligent reflecting surface (IRS) to reflect wireless radio frequency (RF) communication signals transmitted from the agent device to the client device, the IRS comprising a two-dimensional array of individually controllable RF reflecting elements; providing a jamming device which radiates jamming signals with random power to confuse the adversary device in detecting the existence of the communication between the agent device and the client device; and establishing a covert RF communication link between the agent device and the client device using the IRS that optimizes the transmission probability, transmit power at an agent, and the reflection matrix of an IRS for covert RF communications.

The invention provides a cooperative interference probability optimization covert communication method driven by a diffusion model. The method comprises the following steps: constructing a covert communication system comprising a legal sending end, a legal receiving end, an eavesdropper and a friendly interference node, and setting a channel model and a signal transmission strategy of the covert communication system; the detection error probability of the eavesdropper is calculated; constructing an optimization problem by taking maximization of the safety energy efficiency of the covert communication system as a target; modeling the optimization problem into a double-layer Markov decision process, solving the double-layer Markov decision process through a hierarchical deep reinforcement learning algorithm based on diffusion model enhancement, and solving to obtain the maximum safety energy efficiency of the covert communication system. According to the method, the concealment, the transmission safety and the interference energy efficiency of the covert communication system can be comprehensively measured. According to the method, a layered deep reinforcement learning framework based on diffusion model enhancement is designed, the interference duration proportion and the interference power are optimized at the same time, and the concealment and the safety are improved in a more efficient mode.