Study On Outsourced Multi-Authority ABE With Updatable Policy

Attribute-Based Encryption(ABE)has a significant advantage over the traditional public-key cryptography,because it implements one-to-many encryption rather than one-to-one encryption.ABE is considered an important tool for solving data security issues and achieving fine-grained access control issues.So ABE program is more and more applied to the actual,but there are some problems.First,the traditional single authority ABE programs cannot meet the different agencies in a distributed application environment requirements,easy to form a system bottleneck;Second,when ABE is applied to the cloud storage system,there still have a challenge that the design of the user's attribute revocation mechanism;Third,because the security of the ABE scheme is based on mathematical,the key generation,encryption and decryption of the scheme involves a large number of complex mathematical calculations.Although domestic and foreign scholars put forward a lot of outsourcing ABE program,but mainly for decryption outsourcing program,to ensure security of the system and not revealing the information,the system will outsource the main calculation to the cloud service provider,and finally the user can restore the message by simply calculating,but the key generation and encryption also involves a large number of exponential operations and paired operations,the calculation is still large,which virtually give users and data owners to bring great challenges.Based on the above-mentioned problem,this paper proposes a multi-authority ABE scheme with policy update and outsource in cloud storage,which can solve the security problem caused by the single attribute authority and solve the application problem of ABE scheme.In some of the existing programs,when some of the attributes changed,the work of the ciphertext update is done primarily by the data owner,which is time consuming and inefficient.In our scheme,the data owner generates an update key,uploads it to the server,and the server completes the ciphertext update according to the update key,which provides an efficient and flexible ciphertext update strategy.In order to solve the ABE program there are a lot of computational problems.The scheme proposed in this paper will be key generation,encryption,decryption are outsourced,to achieve the user to minimize the amount of calculation.Then the security analysis of the program,finally through the experiment to prove the correctness and efficiency of the program.