37 results about "Pseudo randomness" patented technology

The invention provides a digital image encryption method based on a chaotic system and a nucleotide sequence database. The method comprises the following steps: image pixel positions are scrambled by chaotic mapping index sequence; an image pixel value undergoes DNA coding, and the DNA-coded image pixel value and a DNA sequence in a nucleotide sequence database undergo base operation; and the DNA-coded pixel undergoes base replacement according to a quanternary hyperchaos sequence generated by a hyperchaos Chen system, and confusion and diffusion properties are further enhanced by iteration of a ciphertext feedback and chaotic system. By means of sensibility and pseudo-randomness of chaotic mapping to initial conditions, by combining inherent spatial configuration and unique information processing capability of DNA molecules and through transformation and operation between two chaotic sequences, a DNA sequence database and pixel gray value, the purpose of confusion and diffusion is achieved so as to realize encryption of digital images. It shows through experimental results that the method has a large keyspace, has strong sensitivity to a secret key and can effectively defense attack operations such as statistical analysis, exhaustion analysis and the like.

The invention proposes an incoherent frequency compensation and demodulation method and a demodulation device which have low power consumption, high performance and use the pseudo-randomness of the received signal phase and the PN code to realize the wireless digital communication data demodulation which has short distance, low power consumption and low packet loss rate through the carrier frequency error compensation and data recovery; the demodulation device is composed of a digital low-converter, a channel filter, a phase arithmetic unit, a phase differentiator, a frequency compensator and a PN code de-spreading correlator; the intermediate signal is converted into the plural baseband signals which are processed with channel outer band noise filtration so that the amplitude-time signal is converted into the phase-time signal; the phase differentiator is adopted to differentiate the phase-time signal; the frequency compensation circuit compensate the carrier frequency according to the phase difference signal and the phase average signal; the carrier frequency and the phase recovery circuit are avoided; the PN code correlator group processes the matching demodulation towards the semi-cosine shaping OQPSK and MSK signals of the DSSS directly to recover the baseband data; the incoherent frequency compensation and demodulation method and the demodulation device has the advantages of simple circuit, less quantity of hardware, easy low power consumption integration, good demodulation performance and being applicable to the wireless satellite navigation and the short-range wireless communication device with batteries as the power supply.

The invention provides an OPC UA (OPC Unified Architecture) key exchange method based on chaotic RSA encryption, and relates to industrial data communication and information security. The method is mainly used for securely exchanging key information between an OPC UA client and a server in order to complete a conversion process from asymmetric encryption to symmetric encryption. According to the method, a large prime number meeting requirement is generated according to the pseudo randomness of a chaotic sequence in order to replace a step of generating a prime number in traditional RSA. Through the establishment of a security channel between the OPC UA client and the server, a security mechanism of current communication is negotiated, and then key exchange is carried out. Through generation of the large prime number by the principle of chaos in the method, the encryption efficiency between OPC UA systems is increased. Moreover, the security of a key in an exchange process is ensured through design of a strict authentication and communication flow; symmetric encryption communication between OPC UA is realized; and the security and timeliness required in an industrial information exchange system are realized.

The invention provides a color two-dimensional bar code encryption and decryption method in a high-dimensional chaotic system. According to the method, application methods of a DNA sequence and an SHA-256 algorithm in the high-dimensional chaotic system are defined, and the DNA sequence and the SHA-256 algorithm are applied to encryption and decryption of a color two-dimensional bar code. An encryption method relates to steps such as generating a key and an initial value; carrying out coding through utilization of DNA; carrying out exclusive or operation on color two-dimensional bar code and key matrixes; carrying out color two-dimensional bar code matrix value substitution; carrying out decoding through utilization of the DNA; and synthesizing the encrypted color two-dimensional bar code. A decryption method is reverse operation for the encryption method. From a simulation experiment, it is observed that the method provided by the invention has relatively high pseudo-randomness, forgery prevention and attack resistance.

The invention discloses a light DFT-S-OFDM secure transmission system based on a digital chaos. The system comprises three encryption steps all together, i.e., insertion of an OFDM synchronous training sequence, DFT matrix signal preprocessing and subcarrier mapping, wherein an OFDM synchronous training sequence and a subcarrier mapping mode are both generated by a chaotic system, DFT matrix element parameters m and n are generated by the chaotic system, by use of initial value sensitivity and pseudo randomness of the digital chaos, encryption processing is performed on DFT-S-OFDM signals, and thus secret transmission is realized. On one hand, since a security system secret key space is huge, the security of high-speed information transmission can be effectively enhanced, and at the same time, since a DFT matrix can substantially reduce a peak average power ratio (PAPR) of OFDM signals, the performance of the transmission system is also improved; and on the other hand, since multiple iteration optimization and multiple discrete Fourier transformation operation are unnecessary in a DFT matrix signal processing system, the whole system has the following advantages: the system architecture is simple, the calculation amount is small, the transceiver cost is low, and transmission of sideband information is unnecessary.

The invention relates to an image encryption method based on a five-dimensional hyper-chaotic system. The method comprises the steps of generating a first random sequence, a second random sequence anda third random sequence based on the five-dimensional hyper-chaotic system; Scrambling the plaintext image by using the generated first random sequence to obtain a scrambled image; Calculating to obtain a diffusion sequence by using the generated second and third random sequences and the obtained scrambled image; And transforming the diffusion sequence to an image matrix to complete encryption ofthe image. According to the embodiment of the invention, based on the five-dimensional hyper-chaotic system, the pseudo-randomness of the sequence and the scrambling effect of the image are improvedthrough the new chaotic sequence generation method and the new image scrambling method, so that the image has higher encryption security.

The invention provides a mark generating method for generating a unique mark for a data entity according to the service logic of an information system, comprising the following steps of: designing a name generator used for the information system according to the service logic of the information system; using the name generator to generate a name for the data entity; and using an information digest algorithm to generate an information digest from names generated by the name generator, and using the information digest as the unique mark of the data entity. In addition, the invention also provides a mark generating device. The mark generating method and the mark generating device can solve the problems of the unpredictability and the pseudo-randomness of services of the traditional unique mark generation type and can also ensure the characteristics of the mark, such as the uniqueness, the length fixity, the information hiding and the like, based on business rules.

Provided are a node device of a beacon-enabled Wireless Personal Area Network (WPAN) managing a channel resource and a method thereof. The node device may generate a pseudo random binary sequence (PRBS) and generate a hopping sequence based on a number of available channels using the PRBS, thereby generating a hopping sequence having a characteristic of pseudo randomness and selecting a channel to be hopped, using the hopping sequence.

The invention discloses a multisource input true random number generator circuit structure. Multiple noise generating circuits of different types are used as noise sources; with input selection of an option switch, the noise is input into a sampling correcting circuit; on one hand, the input result enters into an output processing module, and on the other hand, the input result enters into a random number counter; the random number counter counts the generated random number, and feeds back the output result to the option switch; then the signals are randomly selected from the multiple noise generating circuits and then output. In the process, due to the randomness of selection from the multiple noise sources, the randomness of the sampling correcting output, and the randomness of application of the random number counter, the pseudo-randomness generated by the original single noise generating circuit due to long-time working can be eliminated wholly. Proved by the theory and experiments, the true random number generator utilizes multiple noise sources and the random number counter to realize feedback, so that the randomness of the long-range data is better than the original random number generator realized by the single noise source.

The invention provides a forming method of a radio frequency stealth transmitting beam based on a four-dimensional antenna array. Only simple timing sequence design is needed to achieve similar multiple input multiple output MIMO and phase controlled MIMO arrays and even better detection performance, a radar is different from a traditional radio frequency stealth radar, and good radio frequency stealth performance can be given to the radar due to pseudo-randomness of timing sequence. The invention further provides a forming system of the radio frequency stealth transmitting beam based on the four-dimensional antenna array based on the forming method. The forming system has the characteristics of being simple in structure, and easy to realize. According to the forming method and system of the radio frequency stealth transmitting beam based on the four-dimensional antenna array, the generation condition of four-dimensional antenna timing sequence is controlled, under the condition that aradiation signal with good radio frequency stealth performance is ensured, orthogonality among sub-arrays of transmitting antennas or different radio frequency switches is easily realized, a receiving end receives an echo and carries on the signal processing, and information of multiple targets can be simultaneously obtained.

The invention relates to a method for designing a fully randomized silicon-based waveguide optical grating on the basis of a chaotic particle swarm optimization algorithm. Uniform optical grating design parameters are made inhomogeneous, the overall variation of the optical grating is designed as the change of each periodic block, and a coupling efficiency value under the case of each parameter isan adaptation degree in the particle swarm optimization algorithm; when a particle swarm evolves to the next generation, each particle updates itself by tracking two optimal solutions including pbestand gbest; when a boundary position value is taken as a particle value, chaotic variable processing is conducted, and a global search function is achieved; an initial value is provided for a chaoticvariable, and a group of random sequences with ergodicity and pseudo-randomness are generated through iteration of a chaotic iterative equation; a coupling efficiency standard required for the opticalgrating is set, when a particle swarm optimization result reaches the required standard, the process stops automatically, and the particle value corresponding to the adaptation degree is the demandeddesign parameter value. Systematic design of the fully randomized optical grating is achieved, and design parameters and the coupling efficiency of the optical grating can be effectively and quicklyobtained.

The invention discloses a radar signal design method capable of resisting intermittent sampling and forwarding interference, which comprises the following steps of: starting from the angle of waveform design, coding each symbol in a time domain by adopting a chaos sequence with good pseudo-randomness, and adding a part of signal data in each path in the time domain into equivalent redundant codes according to random arrangement. The MIMO radar performs multi-channel sending and receiving and multi-channel matched filtering on the anti-interference radar signal, so that the pseudo-randomness of the radar waveform pulse is increased, the correlation between the radar echo and the intermittent sampling interference is reduced, and the intra-pulse correlation of the radar signal is reduced, and therefore, and the radar signal has the characteristic of resisting the intermittent sampling interference, therefore, the interference of ISRJ false targets can be effectively reduced and meanwhile, the method does not conflict with a common filter design method, and can be used in a superposed manner.

The invention relates to a radar signal optimization method and device, computer equipment and a storage medium. The method comprises steps of carrying out the optimization design of signal waveform key parameters, the number of subcarriers, the number of chips and a chaotic initial value through employing the initial value sensitivity and pseudo-randomness of chaotic coding and reducing the correlation between adjacent pulse signals. According to the method, the correlation between adjacent pulses of the radar signal is low, even if an interference party identifies and copies the signal pulse, a certain time is needed in the identifying and copying process, the interference party cannot obtain matching gain with the subsequent pulses, and the interference party can not obtain the matchinggain with the subsequent pulses; therefore, the method has excellent copy-and-forward interference resistance. According to the method, a waveform optimization method is adopted to improve the anti-copy-and-forward-interference performance of the radar, extra calculation does not need to be carried out during signal processing, and the method is more suitable for engineering application.

The invention provides a lightweight key sequence generator based on a chaotic system and an FPGA, and solves the problem that the precision of the chaotic system is limited by hardware resources. Thelightweight key sequence generator comprises a sequence generator module based on a Logistic chaotic system, two nonlinear shift registers, three data selection modules, a filter function H module and an output function Z module. According to the lightweight key sequence generator, a Logistic chaotic sequence is digitalized and is combined with a nonlinear feedback shift register through a certain algorithm; the chaotic system and the non-linear feedback shift register are well combined, and the FPGA-based hardware implementation ensures the pseudo-randomness of the sequence and the securityof the system, enables the code scale to be smaller, and occupies less hardware resources.

The invention provides an image encryption method based on a fractional order Lorenz chaotic system, and a storage medium, belonging to the field of image processing. The method comprises the following steps: constructing the fractional order Lorenz chaotic system, and generating three chaotic sequences; scrambling the pixel position of a to-be-encrypted image P by using any two chaotic sequences; and performing chaotic encryption on a scrambled image pixel value by taking fragment combinations in the three chaotic sequences. According to the invention, the chaotic sequence generated by a new system is utilized to encrypt a gray level image, and an analysis result shows that a new fractional order system has more advantages in application in related fields such as image encryption and communication secrecy, and has more complex dynamic characteristics, stronger pseudo-randomness and unpredictability, strong attack resistance, larger parameter space and higher safety.

The invention discloses an encryption method for a digital archive. The encryption method comprises the following steps of: generating a chaotic matrix by taking a secret key fused with fingerprint information and a user input sequence as an initial state of a system, scrambling the positions of image pixel points through the pseudo-randomness of the chaotic matrix, and executing mod operation on the scrambled image and the chaotic matrix at a corresponding position. Therefore, encrypted pixels are changed, a pixel correlation is reduced, and original image information is protected. Meanwhile, the use of the fingerprint information also ensures the uniqueness of the secret key, and encryption security is improved.