Certificateless Public Key Encryption Scheme With Keyword Search

Currently,cloud server is a powerful platform for data processing and data storage in the era of big data.The function of cloud servers providing storage capabilities for big data has raised widespread concerns about data security and privacy protection in the cloud.Cryptography is an important technology for securing data,which guarantees confidentiality,integrity,undeniability,etc.Therefore,it is important to research and design cryptographic solutions that meet the requirement of users.Searchable encryption is one of the key encryption techniques in cryptography that allows users to encrypt and upload data to a cloud server,while the server can search for files in the cloud via ciphertext.This technology provides operability for encrypted data and has high practical application value.Analyzing existing searchable cryptographic schemes based on traditional public key cryptography system and identity public key cryptography system that have certificate management issues or key escrow issues.Certificateless traditional public-key cryptography system can overcome not only the certificate management problems of traditional public key cryptography system,but also the key escrow problems of identity traditional public key cryptography system.Based on the needs of data privacy protection of the certificateless public-key cryptography system,it is one of the current hot topics in cryptography research to research and design certificateless searchable encryption schemes to meet the different requirements of users.Combining with the needs of delegation,deniable authentication and ciphertext equality test based on the certificateless cryptosystem,this paper researches the searchable encryption scheme.Specific researches include:(1)A delegation-based certificateless searchable encryption scheme was designed.This scheme adds delegation function to the server comparing to the regular certificateless searchable encryption scheme.The scheme is not to verify the user's legitimacy through a trusted user management center,but to verify the user's legitimacy through the delegation to the server by the data recipient,only users who pass the legitimate verification can perform keyword searches.Under the random oracle model,it is proved that the scheme meets the indistinguishability of adaptive selection keywords.Finally,the simulation experiments and analysis of the scheme were carried out.(2)A certificateless deniable authentication searchable encryption scheme was designed.There are existing certificateless searchable encryption schemes that do not achieve identity privacy protection for senders.In order to solve this problem,a deniable authentication searchable encryption scheme that enables deniability is proposed.In this scenario,the recipient uses its own private key to simulate the cryptographic algorithm to generate a cyphertext,this kind of cyphertext and the cyphertext generated by the sender that using the cryptographic algorithm will make it impossible for third parties to distinguish which party ultimately generated it to achieve deniability and protect the identity of the sender's privacy.Under the random oracle model,it is proved that the scheme not only meets the indistinguishability but also the deniability of the adaptive selection keywords.Finally,the simulation experiments and analysis of the scheme were carried out.(3)A certificateless searchable encryption scheme that supports the ciphertext equality test function was designed.The ciphertext equality test enables the comparison of ciphertext equality between different public key cryptographic data in a cloud environment.However,the existing encryption schemes for ciphertext equality test that do not support keyword search functionality and are costly for communication and inefficient to search.To address this issue,a certificateless searchable encryption scheme has been designed to support the ciphertext equality test function.The scheme supports both keyword search and ciphertext equality comparison between different public key cryptographic data.