Ciphertext multi-keyword grading security retrieval method

Abstract

The invention discloses a ciphertext multi-keyword grading security retrieval method. A ciphertext file set and indexes uploaded by a data owner in a cloud storage server are subjected to grading retrieval. A data user sends a retrieval request to generate a trap door vector; the data owner enables the trap door vector to form a security trap door vector by using a homomorphic encryption algorithmand uploads the security trap door vector to the cloud storage server; the authorized data user can obtain a decryption key and calculate a ciphertext of a trap door and a security index inner product for the cloud storage server; an encrypted correlation score sequence is returned and is decrypted and sorted; first k file identifiers with highest correlation scores are selected to be sent to thecloud storage server; and finally most correlated files are returned to the data user through the cloud storage server. According to the method, the problem of user privacy and data security in a cloud environment is solved; the communication overhead is reduced; and the ciphertext retrieval problem is solved.

Description

Technical field [0001] The invention relates to network ciphertext retrieval, in particular to a multi-keyword hierarchical secure retrieval method for ciphertext. Background technique [0002] At present, the use of hierarchical multi-keyword homomorphic encryption technology to achieve the retrieval of the three comprehensive indicators of ciphertext in terms of security, accuracy and efficiency is the main challenge of the current ciphertext retrieval technology in the cloud environment. The new multi-keyword hierarchical retrieval method has more advantages in the retrieval of document keywords: on the one hand, multi-keyword retrieval provides refined retrieval results; on the other hand, multi-keyword retrieval solves the privacy and data of users under cloud storage The issue of security is also the basis for realizing advanced query functions. [0003] The premise of the comprehensive advantage of this method is that the cloud storage server, as a trusted third party, has ...

AI Technical Summary

Problems solved by technology

In December 2016, JD.com experienced a large-scale data leak, and about 12G of user data information flowed out. These security threats not only seriously hindered the development of cloud computing, but also seriously hindered the efficient use of cloud data

Moreover, there are few literature reports on the solution that can not only perform ciphertext retrieval in terms of efficiency, security and accuracy, but also meet the needs of users.

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