2results about How to "Reduce space complexity" patented technology

This disclosure provides a data storage method and apparatus. The method includes: acquiring target data to be stored; reading a bitmap structure from a database based on a target identifier in the target data; and determining the mode of the bitmap structure. When the bitmap structure is determined to be in a variable-length mode, writing a target time from the target data into a newly added time unit in the data portion of the bitmap structure, wherein the data portion of the variable-length bitmap structure contains at least one time unit. When the bitmap structure is determined to be in a fixed-length mode, setting corresponding data bits in the data portion of the bitmap structure based on the target time in the target data, wherein the storage location of each data bit in the data portion of the fixed-length bitmap structure corresponds to a time point. This method can reduce the space occupied by data storage, thereby reducing storage costs, and improve the efficiency of data retrieval, thereby reducing query latency.

This invention discloses a method, device, and medium for security assessment of number-theoretical transformation modules based on bypass analysis. The method includes: collecting first and second bypass curves generated by the target device during number-theoretical transformation and subsequent polynomial multiplication, and constructing a leakage template accordingly; constructing a number-theoretical transformation factor graph based on the inter-layer mapping relationship of butterfly operations from layer i to L of the number-theoretical transformation; obtaining first and second probability distributions through template matching using the first and second bypass curves respectively; merging the two probability distributions as prior conditions to update and iterate the number-theoretical transformation factor graph; constructing a lookup table for the layer i butterfly operation; reversing the variable node values ​​of the preceding butterfly operation based on the updated factor graph, and recursively backtracking to the first layer input to recover the key; and finally assessing the security of the number-theoretical transformation module based on the recovered key. This method combines number-theoretical transformation factor graphs, probability inference, and lookup table reverse reasoning, improving assessment efficiency and accuracy.