120 results about "Logistic map" patented technology

The invention discloses a DCT domain-based color image digital watermark embedding method and a DCT domain-based color image digital watermark extracting method. The DCT domain-based color image digital watermark embedding method comprises the following steps: before embedding a color watermark image, utilizing Logistic mapping to scramble the coordinates of components R, G and B of the color watermark image; embedding each component of the scrambled color watermark image as watermark sequences to a host image; and according to luminance, contrast and texture complexity, classifying image blocks of the host image. By utilizing human visual characteristics, the watermark components of different strengths can be embedded into image block DCT coefficients of different classes. The watermark image produced by the method has the characteristics of good perception effect and strong robustness and has good resistance to some conventional attacks.

Disclosed is a novel circuit able to generate any logic combination possible as a function of the input logic signals. The circuit is described as a 2 input logistic map circuit but may be expanded to 3 or more inputs as required. Further disclosed is a universal logic array with variable circuit topology. A metallization layer and / or a via interconnection between cells in the array elements produce a circuit topology that implements a Boolean function and / or chaotic function and / or a logic function. The novel circuit provides a circuit topology for secure applications with no obvious physical correspondence between control signal values and input to output mapping. Further disclosed is a network which has a power signature independent of input signal state and output transition. This provides a very useful circuit to protect data from decryption from power signature analysis in secure applications.

The invention discloses a medical image robust watermarking method based on SIFT-DCT, and belongs to the field of multimedia signal processing. The method comprises the steps of firstly, carrying outsymbol encryption on a watermark in a frequency domain by utilizing the properties of a Logistic Map; secondly, extracting an eigenvector by performing SIFT-DCT on a medical image to perform watermarkembedding, associating the eigenvector with a binary watermark to obtain a binary logic sequence, and storing the binary sequence in a third party; and thirdly, extracting an eigenvector by performing the SIFT-DCT on the to-be-tested medical image again, and associating the eigenvector with the binary sequence stored in the third party to carry out watermark extraction. The method is a medical image digital watermarking technology based on the SIFT-DCT, has relatively good robustness, and is especially outstanding for geometric attacks such as rotation, translation, shearing and the like; and watermark embedding does not change contents of original encrypted volume data, so that the method is a zero watermarking technology.

The invention discloses an image encryption method based on fractal and DNA sequence operation, which mainly comprises the steps of: scrambling an original image by utilizing a scrambling sequence generated by adopting a fractal method; then acquiring a DNA template matrix by utilizing a corrected natural DNA sequence; then encoding the scrambled image, and carrying out DNA sequence add operation on a result and the DNA template matrix; and finally utilizing a chaos template matrix generated by Logistic mapping and a matrix obtained after DNA decoding to interact to obtain an encrypted image. The image encryption method has the advantages of high security, good encryption effect and large secret key space, and can effectively resist exhaustive attacks, statistical attacks and differential attacks. And the algorithm is easy to implement, the cost is low, and the encryption results can be transmitted through the Internet.

An image duel scrambling method based on three-dimensional Logistic mapping belongs to the field of digital image processing. The image positive scrambling process comprises the steps that firstly an IMAGE to be scrambled with the size of M*N is obtained, 5*M*N three-dimensional Logistic mapping function values are respectively obtained according to a three-dimensional Logistic mapping formula, the Logistic function values of last M first dimensions, last N second dimensions, and last M*N third dimensions of the 5*M*N three-dimensional Logistic mapping function values are obtained and sorted in an ascending mode respectively, and position sequences of an index 1, an index 2 and an index 3 are obtained; pixel position scrambling is conducted on the IMAGE by utilizing the sequences of the index 1 and the index 2, and an Image is obtained and converted into a single-dimensional image; an xor operation is conducted on the image and a result obtained through a reminder operation of the index 3 and 255, an image pixel value is changed to obtain an image fig, and the size of the fig is converted into the size of the IMAGE to obtain an image FIG which is a scrambling image. According to the image duel scrambling method based on three-dimensional Logistic mapping, the function value sequences of the three-dimensional Logistic mapping are utilized to respectively change the pixel position and the pixel value of the scrambling image, dual scrambling to the image is achieved, and the image duel scrambling method has the advantages of being high in generality and good in safety.

The invention relates to a robust watermarking method on the basis of DFT (discrete Fourier transform) and a Logistic Map, and belongs to the field of multimedia signal processing. The robust watermarking method includes preprocessing and embedding watermarks and then extracting and reducing the watermarks, and particularly includes steps of (1), generating a binary encrypted matrix by the aid of the Logistic Map; (2), obtaining encrypted watermarks; (3), performing DFT for an original image and extracting feature vectors; (4), generating a binary logic sequence by the aid of the feature vectors and the chaotically encrypted watermarks to complete the process for preprocessing and embedding the watermarks; (5), performing DFT for an image to be measured to extract vectors of a feature; (6), extracting watermarks by the aid of a Hash function and the binary logic sequence generated when the watermarks are embedded; (7), generating a binary encrypted matrix by the Logistic Map; and (8), solving the reduced watermarks so as to complete the process for extracting and reducing the watermarks. The robust watermarking technology has a high practical value in the aspect of protecting personal information of patients during remote medical treatment.

The invention discloses an encrypted face recognition method based on a ciphertext domain. The encrypted face recognition method belongs to the field of multimedia signal processing. The encrypted face recognition method comprises the steps of: firstly, encrypting face images in a frequency domain by using nature of a Logistic Map; extracting face eigenvectors through performing DTF transform on encrypted images; and performing encryption on a face to be detected in a transform domain, extracting encrypted feature eigenvectors in a DFT transform domain, and carrying out face recognition through calculating similarities among the eigenvectors. The encrypted face recognition method is an encrypted face recognition technology based on the ciphertext domain, and has good resistance to conventional attack, geometric attack, occlusion, lighting and the like attacks.

The invention relates to a quantum chaos-based parallel image encryption method. The invention aims to solve the defects of a current traditional serial chaotic encryption algorithm. According to the method of the invention, a sequence generated by hyperchaotic Lorenz mapping and Chen mapping is used as an input sequence for parallel encryption; a generated intermediate ciphertext is adopted as the input of quantum logistic mapping; three-dimensional Baker scrambling operation is performed; and therefore, plaintext information can be hidden. As indicated by experimental simulation, the encryption speed of the algorithm of the invention is higher than that of the traditional serial encryption algorithm, the algorithm of the invention can effectively resist statistical attacks and differential attacks to achieve a very good encryption effect.

The present invention discloses a noise auxiliary encryption and signal recovery method of a broadband access network. The method is characterized in that noise signals of pilot frequency subcarriers and preambles, namely M+1 noise QAM symbols n1 to n(M+1), and the distribution of the pilot frequency subcarriers are obtained by the one-dimensional logistic mapping (chaotic mapping), and an N*N switching matrix Msw is obtained according to the distribution of the pilot frequency subcarriers. During the encryption process, an original signal and the noise signal are switched by the switching matrix Msw, so that not only the noise signal is inserted in the original signal, but also the distribution of the original signals is changed. At a receiving terminal, the pilot frequency subcarriers and the preambles loaded with the noise signals recover the original signals by a method reverse with a sending terminal. According to the present invention, and during the encryption process, the noise signal used for signal recovery is added in a useful signal randomly, and the original useful signal itself is disturbed and reconstructed, so that an invalid intruder can not obtain all useful information from an encryption signal if not having a secret key.