A Searchable Encryption Scheme Resilient To Keyword Guessing Attacks In An Open Channel

With the popularity of big data technology,more and more people are encrypting data and storing it on cloud platforms.This allows users to obtain increasingly powerful storage capabilities and high-speed data processing capabilities in the cloud without revealing their privacy.However,the traditional retrieval method needs to download the ciphertext and decrypt it locally,which not only reduces the retrieval efficiency,but also leads to security problems.Searchable encryption technology is a technology that can realize the search for specific keywords in ciphertext and avoid the risk of data leakage under the premise of ensuring data security.This method can provide users of cloud computing services with better data protection,and provide better convenience for data management and use of cloud platforms.However,most of the existing searchable encryption schemes cannot resist keyword guessing attacks when the communication channel can be monitored and hijacked or the cloud server is honest and curious.In response to the above problems,this thesis studies public key searchable encryption technology,identity-based encryption technology and certificateless encryption technology,and proposes three methods that can resist four known keyword guessing attacks in open channels(choose key word guessing attack,offline keyword guessing attack,online keyword guessing attack and internal keyword guessing attack).The main contributions of this thesis are as follows:(1)A public key searchable encryption scheme against keyword guessing attacks in open channels is proposed.The scheme can defend against four known keyword guessing attacks.While greatly improving the security of the public key searchable encryption scheme,the encryption keywords and trapdoor generation algorithm of the scheme are also greatly improved.(2)A public-key searchable encryption scheme against keyword guessing attacks in an identity-based public channel is proposed.This scheme introduces the identity-based cryptosystem into the first scheme,uses identity as the public key,simplifies the key management operation,and has higher scalability.Like the first scheme,this scheme can resist four known keyword guessing attacks,and compared with other identity-based searchable encryption schemes,this scheme’s encryption keywords and trapdoor generation algorithms are more efficient.(3)A searchable encryption scheme that is resistant to keyword guessing attacks in an open channel without certificates is proposed.This scheme introduces a certificatefree cryptographic system.This scheme not only does not require complex and cumbersome digital certificate authentication and maintenance,but also protects the user’s identity from being leaked.In terms of security,this scheme can still resist the four known keyword guessing attacks and is superior to similar schemes in terms of encryption keywords and trapdoor generation efficiency.In summary,this thesis mainly focuses on the security of public key searchable encryption,solving the known four kinds of keyword guessing attacks,and proposes three versions of searchable encryption schemes against known four kinds of keyword guessing attacks,and all three schemes have good efficiencies.