Ciphertext search method based on word-for-word indexing

Abstract

The invention discloses a ciphertext search method based on word-for-word indexing, which comprises the following steps: building word-for-word index information of character-type encrypted attribute in a base table, wherein the word-for-word index information is composed of partial characters selected after plaintext with encrypted attribute is encrypted word for word; and during searching, firstly converting the original search condition related to the encrypted attribute into a middle search condition of the word-for-word index information related to the encrypted attribute, then carrying out primary search in the base table by using the middle search condition, and finally carrying out precise search in the middle decrypted result by using the original search condition. The invention can previously search the content of ciphertext attribute without encryption to obtain a middle result set with relatively high accuracy, thus the method reduces the expenditure for decrypting the middle result set and has higher search performance.

Description

technical field [0001] The invention belongs to the technical field of database application in computers, and specifically relates to a method for efficiently retrieving encrypted character type data. Background technique [0002] Outsourced database is an emerging data management model. In this mode, enterprises or users store data in the database service provider (Database Service Provider, referred to as DSP) side, and use the data through the Internet, thereby reducing the cost of data management and maintenance. However, since the database is stored on the DSP side, the sensitive and important document data in it usually needs to be encrypted for security reasons. Because the encrypted ciphertext document data loses the original features of the plaintext, it must be retrieved by special ciphertext retrieval technology. The existing ciphertext retrieval technology can be divided into two categories, one is the ciphertext retrieval technology without index, and the othe...

AI Technical Summary

Problems solved by technology

However, most of the existing index-based ciphertext retrieval techniques can only deal with numerical data, and for character-type document data, there is still a lack of efficient ciphertext retrieval methods.