Research On Traceable Attribute-based Encryption Technology For Cloud Computing

With the widespread application of cloud computing technology,more and more users store data in the cloud through cloud services.However,the separation of ownership and management of cloud data from each other,and the semi-trusted nature of cloud service providers,make the sharing of cloud data face significant challenges.As a scalable one-to-many encryption mechanism,attribute-based encryption provides a secure data sharing method for cloud storage.However,in attribute-based encryption,different users may have the same decryption key,and the semi-trusted attribute authority may also distribute the decryption key to illegal users,which causes the problem of key leakage.In order to locate the source of the key breach and determine which user(s)or attribute authority did,traceability can be added to the attribute-based encryption.Therefore,research on traceable attribute-based encryption technology for cloud computing has important theoretical significance and application value.The main research work of this paper includes:(1)This paper introduces the research background and significance of traceable attribute-based encryption,analyzes the research status of attribute-based encryption at home and abroad,and outlines the related theories of attribute-based encryption.(2)Aiming at the key leakage in ciphertext-policy attribute-based encryption and the application scenarios for resource-limited mobile devices,we study the online/offline ciphertext-policy attribute-based encryption scheme with user and attribute authority accountability that supports large universe of attributes on the prime order group.We embed the user's identity information into his(her)private key to achieve accountability,and use online / offline encryption technology to transfer most of the encryption overhead to the offline stage to save the resources of mobile device.The scheme is proven selectively secure in the standard model.We also perform a performance comparison analysis with related schemes.(3)Aiming at the problem of key leakage in ciphertext-policy attribute-based encryption and the privacy requirements of access policies,we study the traceable ciphertext-policy attribute-based encryption scheme with hidden access policies thatsupports large universe of attributes on the composite order group.We embed the user's identity information into his(her)private key to achieve white-box traceability,and hide specific sensitive attribute values in the access policies into ciphertext to achieve policy hiding,and use decryption test technology to improve decryption efficiency.The scheme is proven adaptively secure in the standard model.We also perform a performance comparison analysis with related schemes.The innovations in this article include:(1)An online/offline ciphertext-policy attribute-based encryption scheme with user and attribute authority accountability that supports large universe of attributes is proposed.The scheme achieves accountability by embedding the user's identity information into his(her)private key,and uses online / offline encryption technology to transfer most of the encryption overhead to the offline stage.The scheme is proven selectively secure in the standard model.It has the characteristics of accountability of user and attribute authority,online / offline encryption,large universe of attribute and high expressiveness of access structure.Performance and security analysis shows that the scheme has stronger accountability and the encryption overhead is mainly in the offline stage,which is suitable for application scenarios where mobile devices with limited resources are used for encryption.(2)A traceable ciphertext-policy attribute-based encryption scheme with hidden access policies is proposed.We embed the user's identity information into his(her)private key to achieve white-box traceability,and hide sensitive attribute values in the access policies into ciphertext to achieve policy hiding,and use decryption test technology to improve decryption efficiency.The scheme has features such as user traceability,policy hiding,large universe of attribute,adaptive security and high expressiveness of access structure,which is suitable for application scenarios where access policies with high privacy requirements.Performance and security analysis shows that the scheme optimizes the decryption operation,reduces the decryption overhead and improves the decryption efficiency.