Research On Searchable Public-key Encryption For Cloud Storage

With the flourish of the mobile Internet industry and the Internet of things technology,data over the internet gradually presents the characteristics of high growth rates,large-scale and multi-type.As one of the key technologies to reduce data management costs and improve data usability,cloud storage has attracted much attention from the industry and academia.More and more companies,individuals or government agencies are increasingly willing to outsource their valuable data to the cloud for enjoying high-quality services anytime,anywhere.However,data security and user's privacy are greatly threatened and challenged because the data is out of the actual control of the owner and the cloud may be incredible.Meanwhile,continuous information leakage events remind that security designs are urgently needed to facilitate the application of cloud storage.Searchable encryption can achieve a secure search of encrypted data without disclosing the data privacy,thus effectively balancing the contradiction between data security and data usability.Unfortunately,most existing searchable encryption schemes still suffer from weak security or inefficiency in practical applications,especially searchable public-key encryption.Starting from the requirements of security and application in cloud storage systems,we research on the searchable public-key encryption with practical security,and have obtained certain research results in terms of resisting keyword guessing attacks,pairing-free,forward security,and lightweight search.These research results provide a theoretical foundation and technical guarantee for promoting the wide application of searchable encryption technology.The main contributions of this dissertation are summarized as follows.(1)To address the problem of the keyword guessing attack,a searchable public-key authenticated encryption scheme is proposed based on bilinear pairing.The scheme can resist the keyword guessing attack by ensuring only legitimate users can produce keyword ciphertexts by leveraging Diffie-Hellman shared secret key to encrypt data.(2)To reduce the computation costs of the overall scheme,a pairing-free searchable public-key authenticated encryption scheme is proposed based on dual-server architecture.The scheme inherits the security properties of a searchable public-key authenticated encryption scheme and is very practical because it avoids the use of bilinear pairings.(3)To address the problem of the file-injected attack,a forward secure searchable public-key authenticated encryption scheme is proposed based on the design idea of the symmetric searchable encryption scheme.The scheme has a strong security level because it can resist the inside keyword guessing attack and support forward security.(4)To improve the search efficiency,a lightweight searchable public-key authenticated encryption scheme with forward privacy is proposed by leveraging the hidden structure.The scheme inherits the security properties of a searchable public-key authenticated encryption scheme with forward security,and its search performance is closed to that of some practical searchable symmetric encryption schemes.To sum up,four practical and secure searchable public-key encryption schemes are proposed to address the shortcomings of existing schemes.These proposed schemes are provable security,and have better efficiency in comparison with other schemes.