Research On Key-insulated Aggregate Signature And Its Applications

With the development of information technology,digital signature has been widely used in every field of daily life,and various types of signatures applicable to different occasions have emerged.In some special applications,we need to transmit and verify many signatures,which can lead to a large amount of resource consumption.So aggregate signature is generated,the aggregate signature can save the bandwidth used in information communication,save the storage space of signatures,and reduce the workload of signature verification.With the rapid development of computer network and electronic commerce,more and more passwords have been used on mobile devices,the key leakage has become a serious problem in the security of cryptographic system.In order to reduce the harm caused by the key leakage,the key-insulated mechanism is proposed,which updates the user's private key in each time period by means of an assistant.Even if the attacker gets the key of some period,he can't get the key of other period,so the key-insulated mechanism has forward security and back security.The key-insulated aggregate signature can be widely used in every field of daily life.Protection of users' keys is essential in any password usage scenario.Key insulated signature can effectively protect the privacy of users.and aggregate signature can meet the needs of various occasions that need to collect multi-user's information,in the information today,people use the network more and more to meet their various needs,aggregate signature can be well adapted to this large data age.Therefore,the key-insulated aggregate signature can make reasonable use of resources in many situations and guarantee the key security of multiple users,so it has a good application prospect.This thesis studies the aggregate signature and key-insulated system,committed to the design of a more secure and efficient signature scheme,the results achieved are as follows:1.In order to overcome the problem of key leakage in identity-based aggregate signature,this thesis proposes an identity-based key-insulated aggregate signature scheme without using bilinear pairs.It has the nature of aggregate signature,and satisfies key-insulated security,strong key-insulated security and secure key update.Because there is no bilinear pair in the whole scheme,the calculation is smaller and more efficient.2.In the certificateless signature system,key leaks are also unavoidable.On the basis of the above identity-based signature scheme,this thesis further proposes a key-insulated certificateless aggregate signature scheme without using bilinear pairs,which solves the problem of certificate management and key escrow.This thesis analyzes the security of the three kinds of attackers,such as user attackers,negative dishonest KGC,positive dishonest KGC,and it also has higher efficiency.3.In order to improve the security of the scheme,this thesis attempts to introduce a parallel key-insulated mechanism to reduce the harm caused by the key leakage of helper's key.