4 results about "Collision resistance" patented technology

The invention relates to a three-dimensional model fingerprint generation method and system, a terminal and a storage medium. The method comprises the following steps: identifying a file type, analyzing a file structure for the file type containing structured entity information, and extracting triangular mesh entity data; executing a block sampling strategy based on the file size for the file type which does not contain the structured entity information; counting the total number of triangular facets for the triangular mesh entity data, and selecting an adaptive hierarchical sampling strategy according to the total number of the triangular facets; triangular surface area sampling is carried out on a triangular mesh entity, a sampling block-jumping block alternating traversal mode is adopted, and compared with an existing mode, the performance is improved by 69-83 times; besides, a two-level Hash structure is adopted, the first level is to calculate the MD5 value of the area accumulated sum for each sampling block, the second level is to calculate the overall MD5 value for the connection sequence of all block level MD5 values, and the two-level structure enhances the uniqueness and collision resistance of fingerprints.

The invention provides a Hash function construction method based on dynamic feedback quantum walk. The Hash function construction method comprises the following steps: step 1, realizing Hash function initialization based on dynamic feedback quantum walk; 2, realizing dynamic feedback quantum walking evolution; 3, obtaining the probability distribution of the final quantum state corresponding to each vertex on the two-dimensional grid points through projection measurement; and 4, executing a post-processing method, processing the probability of each vertex on the two-dimensional lattice points through interception and modulo operation, and connecting to obtain a final hash value. According to the method, the message is mapped into the initial parameter of the coin operator, so that the sensitivity of the hash function to the initial message is improved; meanwhile, a dynamic feedback mechanism is introduced to adjust coin operator parameters, the quantum walking evolution process is controlled to optimize quantum state probability distribution, and collision resistance and uniformity of a hash function are improved. According to the method, a high-safety and high-robustness scheme is provided for Hash function construction based on quantum walking.

The present invention relates to a method for implementing hashing with high preimage resistance, collision resistance, and avalanche effect using a neural network model. A message hashing method according to an embodiment of the present invention comprises the steps of: generating a first random number dataset by setting each element of a vector having a first length as a random number, and generating a second random number dataset by setting each element of a vector having a second length shorter than the first length as a random number; supervised learning of a merge block using a first training dataset in which input / output data is composed of the first random number dataset; supervised learning of a hash block using a second training dataset in which input / output data is composed of the first and second random number datasets, respectively; generating a plurality of units by dividing a target message by the first length and sequentially inputting the plurality of units into the merge block serially connected by the number of units; and determining a digest having the second length by inputting the output of the serially connected merge block into the hash block.

The invention discloses a bionic thin-walled structure crashworthiness analysis method based on finite element simulation, particularly relates to the technical field of computer-aided engineering simulation, and is used for solving the problem that the crashworthiness of a complex bionic thin-walled structure is difficult to systematically evaluate in the early stage of design in the prior art. The method comprises the following steps: establishing a three-dimensional geometric model, carrying out finite element grid division, constructing a finite element model for collision simulation, then applying a dynamic impact load to execute collision calculation, extracting node coordinate data, and converting a structure dynamic deformation process into topological characteristic evolution through persistent coherence analysis; a distance-based filtering process is adopted to generate a filtering complex sequence, a persistence graph is obtained by calculating homology group evolution, quantitative indexes, including an average life cycle and persistence entropy, representing topological feature persistence are extracted, then a performance balance graph is constructed, Pareto leading edge distribution is recognized through a non-dominated sorting algorithm in multi-objective optimization, and the performance balance graph is obtained. And the scheme screening of the collision resistance of the bionic thin-wall structure is realized.