Research On Key Generation From Wireless Channels Based On Reed-Solomon Codes

With the increasing numbers of mobile terminal devices,wireless communication has become an inaccessible part of our life.On the other way,due to the openness of wireless communication,the problem of information security has attracted more and more attention.With the inability of the traditional encryption method based on computational complexity to guarantee the security required by the system because of the rapid development of hardware,physical layer security(PLY)has attracted more and more attention.Key generation technology from the wireless channel is an important branch of physical layer security technology.This scheme uses the nature of the wireless channel to generate shared secret keys between legitimate communication parties to encrypt the transmission information for realizing the confidentiality of communication.Firstly,this paper proposes an information reconciliation scheme based on Reed-Solomon(RS)codes for the possible information leakage in the information reconciliation stage,which transmits the check symbols encoded by linear error correction code to the party requiring bit error correction through the common channel.In this way,the information reconciliation can be completed in case of disclosing the information sequences of the key secrets as little as possibleHowever,due to the diversity and complexity of the wireless channel,the RS codes with a single code rate cannot ensure that most of the requirements of information reconciliation can be completed.If the error correction fails,the key generation rate will be reduced,which will seriously affect the performance of the system.Therefore,this paper adds the concept of code rate adaptation based on the above-mentioned information reconciliation method.When the error correction cannot be realized,the communication parties gradually reduce the number of symbols used to generate the key secrets based on the set parameters.By reducing the code rate of generating the error correction codes can improve the error correction performance and complete the error correction information reconciliation between the communication parties under the condition of reducing the key generation rate as little as possible.Finally,this paper uses Zigbee to build a wireless communication system,which uses a Zig Bee module with a single antenna and raspberry pie to form the legitimate communication parties,Alice and Bob.By alternately sending information sequences in a coherent time,the communication parties detect and collect the received signal strength(RSS),then select the RSS value sequence through the window segmentation mode for single threshold quantization,and finally use RS codes to reconciliation the information of the bit sequence obtained by the legal communication parties for completing the error correction of the bit inconsistency between the communication parties.This paper combines the traditional error correction code method with the physical layer security to realize the key generation technology in the wireless communication process,and verifies the confidentiality of the system through theoretical analysis and simulation,which can meet the needs of the point to point communication environment.Through the experiment of the Zig Bee network system designed in this paper in different scenarios,the information reconciliation scheme with a fixed code rate of RS codes can reach the key generation rate of 6.67bit/s,while the information reconciliation scheme with adaptive code rate can reach the key generation rate of9.93bit/s.