Research On Structure-based Group Key Agreement Scheme In Cloud

Cloud environment brings great changes to the society,and provides new ideas in saving computing resources and broadening storage ways.Under the help of cloud,data sharing becomes the best convenient method of getting information,and has the advantage on collecting data and analyzing data.In the process of data sharing,the security of shared data and the privacy of shared members are matters of concern.On one hand,encrypting data by the session key is a convenient way.In addition,the received messages need be authenticated in order to guarantee the data validity.Additionally,each member provides the equal session key part to realize undistinguished agreement.On the other hand,some people reject data sharing because worrying about exposing privacy,which lead to less data.Meanwhile,a member in data sharing group maybe upload illegal data that not only has a bad influence on collecting information,but also wastes download resources,and is contrary to the original aim.So,two protocols are designed to solve above problems in this paper,which are as follows:(1)A spiral queue-based group key agreement protocolIn this thesis,a group key agreement protocol is presented based on a novel math structure named spiral queue.Each member is correspondence to point of coordinate system one by one.Using divide and conquer idea,members are divided into several subsets by comparing with the vertical and horizontal coordinates.After two rounds communication,each member can derive the same session key.The proposed protocol can derive session key among an arbitrary number group through the unlimited spiral queue structure.Because of the same level and operation of each member,members are load-balanced.Meanwhile,to prevent information being tampered and ensure the availability of information after transmission,it is necessary to provide an authentication service.(2)A structure key-based anonymous and traceable data sharing protocolIn this thesis,a structure key-based data sharing protocol is presented,which use spiral queue structure.All group members derive a session key by spiral queue structure and decrypt data by the session key to protect the shared data.In addition,to dispel user's anxiety and protect privacy,group members use a phony-ID in communication both session key agreement and data sharing.Note that,the phony-ID is computed by hash function,so the real ID cannot be inferred.Meanwhile,the trusted party(TTP)is adopted in the proposed protocol in order to trace the illegal data source.According to matching the receiving message against the storing message,TTP can trace the real ID.