Research On Efficient Public Key Searchable Encryption Scheme

With the population of cloud computing technology,tremendous data is outsourced in the cloud server in the encrypted form to ensure data security and user privacy.Cloud storage service brings convenience to users,at the same time it also brings security challenges.Traditional encryption technology can protect data privacy.However,it is very hard to search over encrypted data.Searchable encryption as a solution has been proposed,it allows user to retrieve the encrypted data by keywords,thus greatly reduce the user's communication and computation overhead,and meanwhile ensures the confidentiality of the data.Searchable encryption is divided into symmetric key cryptography based searchable encryption scheme and public key cryptography based searchable encryption scheme,public key cryptography based searchable encryption has solved the key distribution problem in symmetric key cryptography based searchable encryption and thus received a lot of attention recently.This thesis firstly introduces the research background of public key cryptography based searchable encryption and its research significance,and analyzes the state-of-the-art of searchable encryption,and introduces some related basic knowledge,including the basic knowledge of mathematics and cryptography and basic knowledge of provably security.Then this thesis analyzes the design philosophy of classical PEKS schemes and Re-dPEKS schemes,describing the formal definition and security model of PEKS schemes and Re-d PEKS schemes,and analyzes the computational efficiency and security performance of PEKS schemes and Re-dPEKS schemes.Finally,this thesis makes a deep research on the computational efficiency and security performance of the public key searchable encryption,and proposed an efficient ElGamal based public-key encryption with keyword search scheme and an efficient ElGamal based proxy re-encryption with keyword search scheme.These two schemes use discrete logarithms to construct their encryption algorithms,and also uses the keyword registration technology,so it has high computational efficiency,and can resist offline keyword guessing attacks.