Research On Public Key Authenticated Encryption With Keyword Search In Cloud Computing Environment

In recent years,internet user data has been growing exponentially.Relying on big data and cloud computing technology,the third-party cloud platform has become an ideal choice to deal with the huge amount of data and concurrency.However,users lose control of their data after storing it in semi-trustworthy and curious cloud servers,and their sensitive data is vulnerable to theft.To ensure data security,users store data in the cloud in cryptographic form.However,this practice causes the problem that data on the cloud cannot be efficiently retrieved and shared.Public key encryption with keyword search(PEKS)is a new type of cryptographic language that provides keyword search while ensuring data privacy and security.It is believed that cloud servers can steal users’ sensitive data through trapdoors.To solve the above problems,this thesis improves the public key authenticated encryption with keyword search algorithm from the practical requirements of security in the cloud environment and carries out research on the public key encryption with keyword search scheme in cloud computing environment by combining authentication encryption theory.The main contributions of this thesis are as follows:(1)This thesis proposes a proxy searchable public key authenticated encryption with keyword search scheme to solve the issues of public key encryption with keyword search in third-party ciphertext search authority sharing and inside keyword guessing attacks from cloud servers during the sharing process.Proxy re-encryption technology to ensure that user private key or data is not exposed when sharing data in the cloud,and to prevent any unauthorized third parties from gaining access to or stealing user data during data transmission.So as to resist keyword guessing attacks inside the cloud server.In the design of encryption algorithm,the data sender is required to use its own private key to authenticate the keyword ciphertext to eliminate the ability of adversaries to obtain the keyword ciphertext at will.This thesis investigated the security of this scheme,and demonstrated that it meets the criteria of search trapdoor and ciphertext indistinguishability in the random oracle model.Through theoretical computational analysis and simulation experimental analysis,the performance and practicality of this scheme are further improved compared to the traditional PEKS scheme in the cloud environment.(2)To solve the problems that traditional public key authenticated encryption with keyword search causes serious data redundancy and increased storage cost to the receiver in a multi-user situation,this thesis proposes an identity-based anonymous broadcast authenticated public-key encryption with keyword search scheme.This scheme effectively simplifies the key management of traditional PEKS scheme using identity-based encryption system,and simplifies the public key authenticated encryption with keyword search scheme in multi-user sharing situation using broadcast encryption technique.Meanwhile,this scheme achieves O(1)complexity in the trapdoor generation algorithm to greatly reduce the storage cost of the receiver set members,and uses the server public-private key pairs to realize the scheme for transmission in a security channel free.Under the random oracle model,this scheme’s security proof is demonstrated,with keyword guessing attack and anonymity security among receivers being taken into account.In this thesis,the computational cost and communication cost of the scheme are analyzed by theoretical calculations and simulation experiments.Finally,this scheme is shown to be more secure and efficient compared to the traditional multi-user PEKS scheme.