Research On Ciphertext Retrieval Algorithm In Electronic Mail System

With the progress and development of cloud computing,cloud storage services have become a widespread concern.By storing data in the cloud servers,enterprises and individuals can obtain high-quality email services at a lower cost.Therefore,many companies choose to outsource email services to cloud service providers.However,the email data in the cloud server is usually stored in plaintext,which may face the leakage of sensitive data in the email.A simple solution is to encrypt emails before outsourcing them to cloud servers.However,traditional encryption schemes will destroy the structure of the original data,thus preventing users from querying emails stored in the cloud server,leading to cloud service provision The data processing capacity of the business is limited to a certain extent.However,encrypted email will definitely limit the ability of the cloud service to process data to a certain extent.In this case,effective retrieval encrypted emails containing specific keywords has become an important research subject.The main researches in this paper are as follows:(1)A ciphertext retrieval scheme based on identity authentication for designated server is proposed.The keywords in the scheme are encrypted with the identity information of the designated mail storage server and the data receiver,which can resist offline keyword guessing attacks.In addition,the data receiver generates a trapdoor and sends it to the designated mail storage server for search,ensuring the safety of the retrieval mode.Under the random oracle model,the scheme satisfies keyword privacy security and ciphertext privacy security.(2)A ciphertext retrieval scheme based on identity authentication in encrypted E-mail system is proposed.The scheme uses searchable encryption technology to achieve keyword retrieval of encrypted mail.Combining the advantage of key management based on identity encryption technology,the key management of encrypted mail system is realized.In addition,the scheme performs authentication at the encryption keyword stage and the trapdoor generation stage at the same time,and searches for encrypted mail on the designated server,which satisfies higher security requirements.(3)An identity-based multi-keyword ciphertext retrieval in email system is proposed.The public key searchable encryption that supports multi-keyword search enables data users to retrieve the encrypted data they need from untrusted mail servers.This scheme can realize the effective search of multiple keywords in encrypted email.Under the random oracle model,the scheme satisfies keyword privacy security and trapdoor security.