Research And Application Of Multi-authority Ciphertext-policy Attribute-based Encryption

For the inefficiency of attribute based encryption and the need for privacy protection for access control policies.In this paper,we propose an efficient Multi-Authority Attribute-Based Encryption scheme,and give several solutions to enrich our system according to the reality.The main contributions of this paper are as follows:1.We propose an efficient Multi-Authority Attribute-Based Encryption scheme called MA-CPABE.Compared with the existing schemes,this scheme has improved the efficiency of encryption and decryption while reducing the storage burden.At the same time,learn from the previous literature,we use attribute index instead of attribute to achieve privacy of the access control policy.Finally,the scheme is proved to achieve CPA security.2.Based on the above attribute-based encryption MA-CPABE,we propose a scheme called AMA-CPABE to supports arbitrary-state attribute-based encryption.In this scheme,an attribute can correspond to multiple attribute values instead of boolean values.Then,inspired by the idea of hierarchical attribute encryption,we give another implementation of weighted attribute based encryption AMA-CPWABE.For each attribute value,it has different weight according to its importance;the attribute value with high weight in the user key can decrypt the ciphertext corresponding to the lower weight attribute value.We have a detailed analysis of the above two schemes in terms of efficiency,storage,and security.Compared with other schemes,AMA-CPWABE have greater advantages on both efficiency and user privacy protection.3.We propose an attribute-based encryption scheme H-MA-CPABE that supports horizontal attribute management.Compared with the existing multi authority attribute –based encryption schemes,the H-MA-CPABE scheme has been improved in the following aspects: First of all,the amount of computation is reduced when encrypting data,and by outsourcing the decryption to the cloud,the decrypt burden of the client is highly reduced.The efficiency of encryption and decryption are improved.Secondly,when user's attributes are revoked by attribute authority,The system only update the non-revoked user's key without the need to update the ciphertext;Finally,unlike the previous multi-authority attribute based encryption,in this scheme,the central authority can manage the attribute authorization rights of the attribute authority(AA).