Research Of Multi-tags Anti-collision Algorithm And Security On Key Technologies Of RFID System

RFID is a kind of contactless automatic identification technology to obtain the information of the target,which enables a reader to identify tags via radio frequency communication.Compared with the traditional identification technology,RFID has a lot of advantages of non-contact,anti-interference,strong penetrating power,identifying fast-moving objects,tracking objects in time.RFID technology,which improves the efficiency of management and operation,has wide applications in many fields,such as logistics,tracking,public transport services etc.Two key technologies of the algorithm of tag anti-collision and security authentication protocols in RFID are discussed and studied profoundly in this paper.The main contents are:(1)Based on frame slotted ALOHA algorithm,a novel grouped adaptive allocating slots(GAAS)anti-collision algorithm is presented to solve the problem of collision between multi-tag in radio frequency identification(RFID)system.First reader needs to obtain the time slots chosen randomly by tags and send the results to each tag;Then the tags rectify the time accordingly to the instruction;Moreover the reader skips free and collision time slots,and adaptively distributes valid ones;Finally the tags will be quickly solved in GAAS.When the number of unidentified tags is very large,the tags can be disposed by grouping approach and the frame size can be adjusted dynamically to reduce the processing time.The simulation results show that GAAS has higher identification efficiency and stability,and lower amount of communication.(2)An adaptive searching prefix(AS)anti-collision algorithm for RFID based on encoding is proposed to reduce the identified time of the object tag.The reader makes full use of the collision information to adaptively generate a valid query prefix by asking the tags return the collision coded information.With no idle slots for tags to identify,it reduces the number of queries.Besides,AS has solved the problems of redundant data in the communication between the reader and the tags and other related issues.(3)An authentication protocol with synchronous updated-keys based on Hash function is proposed to tackle security privacy problems in this paper.An updated mechanism of the dynamic tag keys is introduced and a self-synchronized scheme is designed in the protocol,which has achieved the second verification for the tags.The proposed protocol is verified and analyzed by the BAN logic and the attack models in detail.Moreover it has been compared with the existing schemes of security properties and its storage and computational performance.(4)Considering with the security problems for low-cost tags failing to some complexity cryptographic functions of protocols,a novel lightweight security protocol based on chaotic encryption is presented in this paper.By the method of synchronous dynamic updated-keys,the encrypt information is achieved by chaotic sequence.It reduces the cost of the tags,also effectively improves the security of the system.