48 results about "Lorenz system" patented technology

A system and method for encoding zero and one bits for transmission, including generating a first signal from a non-linear chaotic system to represent the one bit, with the signal's embedded vectors being within the non-linear system's attractor set, and generating a second signal from the non-linear system to represent the zero bit, with the signal's embedded vectors being outside the non-linear system's attractor set. The second signal encoding the zero bit can be generated by adding together two chaotic signals arising from the non-linear system initialized with different initial conditions, and weighting the second signal to have approximately the same energy as the first signal. One suitable chaotic systems is a Lorenz system. Systems and methods for decoding a transmitted stream of signals compare a detection statistic of the received stream of signals to a threshold value that depends on the chaotic system.

The invention relates to a chaotic signal generating circuit, comprising a microcontroller, a signal isolating circuit, three D / A switching circuits; each D / A switching circuit comprises 16-bit shift registers and 16-bit DAC registers and shift registers in each D / A switching circuit are connected in series to form a 48-bit shift register. Serial digital signals output by an SPI interface of the microcontroller are transmitted to a serial data input terminal of a first D / A switching circuit through the signal isolating circuit; clock signals and latch control signals output by the SPI interface are respectively transmitted to a clock input terminal and a latch control signal input terminal of the D / A switching circuit through the signal isolating circuit. In the invention, based on the chaotic circuit of the microcontroller, the Euler algorithm is adopted to carry out discretization processing on the continuous state equation of the improved generalized Lorenz system; as a result, theoperation algorithm which can be appropriately realized by the microcontroller is established and folding directions of chaotic attractors and system operation modes are optional.

The invention relates to a 4-neighborhood exclusive or image encryption method based on a hyper-chaos Lorenz system. The method is characterized in that RGE three components of an original color image are extracted, the grey levels of all pixel points in the RGE three components are recorded as a two-dimensional matrix PR, a two-dimensional matrix PG and a two-dimensional matrix PB, scrambling is carried out on the matrix PR, the matrix PG and the matrix PB respectively by means of chaos sequences generated by the hyper-chaos Lorenz to obtain an image pixel matrix PR1, an image pixel matrix PG1 and an image pixel matrix PB1 after scrambling, and 4-neighborhood exclusive or encryption is carried out on the matrix PR1 through reusing of the processed chaos sequences of the Lorenz, the matrix PG1 and the matrix PB1 respectively, so the encryption process is completed. The scrambling and 4-neighborhood exclusive or encryption are carried out on the color image through the hyper-chaos Lorenz system, so the method has the advantages of being large in secret key space, good in safety and strong in plaintext attack resistance and is suitable for image secret communication.

The invention discloses a method for constructing image passwords based on neuron chaotic response encoding. Firstly, the invention converts the digital passwords into the position initial values ​​of the Lorenz system through logarithmic transformation, and obtains the chaotic time series; combined with the user number, the temporal chaos The sequence is linearly transformed to obtain a low-level time series to construct a chaotic square wave excitation signal; the excitation signal is used as the input current of the Hodgkin-Huxley neuron to encode the chaotic response of the neuron, and the moment when the neuron pulse is emitted is recorded; finally Obtain the time interval sequence of neuron pulse firing, convert the one-dimensional time interval sequence into a two-dimensional image code through grayscale mapping, and according to the row and column parameters of the image code. The invention makes full use of the chaotic initial value sensitivity of the Lorenz system and the chaotic parameter sensitivity of the pulse distribution of the neuron model, ensures the irreversibility of the image password, and effectively enhances the security of the identity authentication system.

The invention relates to a different-dimensional switchable chaotic system design method and a circuit; a four-dimensional hyper-chaos system is constructed by adding variables and feeding back control items based on a three-dimensional generalized Lorenz system family; and a switchable different-dimensional chaotic circuit is designed through a plurality of switch controllers in Multisim software. An analog circuit constructed by the invention is convenient to use and easy to realize by hardware, and has relatively lower cost; the designed switchable circuit not only can flexibly realize the switching between a three-dimensional chaotic system and the four-dimensional hyper-chaos system, but also can return to realize the switch among three chaotic systems in the same dimension; and the systems can serve as practical chaotic modulation and chaotic encryption signals, and can be widely applied to the field of information security cryptography with higher requirements on confidentiality and reliability.

The invention discloses an image encryption method based on a Lorenz system optimal sequence and K-L transformation, and a Lorenz chaotic system is selected as a key generator. At the same time, the K-L transformation method is introduced, which effectively improves the performance of the encryption result in the adjacent pixel correlation test. At the same time, this method is relatively easy to implement in subsequent hardware implementations, and finally the Lorenz-based system proposed in this paper is obtained. The image encryption algorithm of optimal sequence and K-L transformation has achieved a good balance between algorithm security and algorithm speed. The encryption algorithm of the present invention is simple and easy to implement, solves the problem of slow image replacement algorithm speed, and at the same time avoids the problem of insufficient security of the image scrambling algorithm, and achieves a good balance between algorithm security and algorithm speed The balance of the image; the index of image pixel correlation is further improved, and the security of the finally obtained image encryption algorithm is further improved.

The invention discloses a feedback switching encryption method based on a double chaotic system. By discretizing the Qi hyperchaotic system, the Qi state variables corresponding to each output channel after the Qi system is discretized are obtained; according to the system state variable output by the Lorenz system, the Whether it is necessary to generate a switching signal, and at the same time, perform an encryption operation on the original bit stream corresponding to the Qi state variable and the image data to be encrypted, and obtain the encrypted ciphertext; according to the generated ciphertext, add a feedback switching link, and according to Feedback results determine whether switching signals need to be generated; the purpose of using the Lorenz system and Qi system, a pair of chaotic systems, to improve the unpredictability of switching signals and the randomness of encryption sequences is achieved, and the security of image data encryption is enhanced.