Research On Secure Commutation In Wiretap Channel

With the development of science and technology,the demand of secure communication system is increasing.On the other hand,the improvement of large scale computing ability makes the traditional cryptography based on decoding complexity more and more unreliable.Therefore,the theory of physical layer security has been put forward by some scholars,trying to analyze the security of the information from the signal level from the perspective of information theory,so as to fundamentally eliminate the possibility of stealing secret information.Wiretap Channel theory is an important research field in physical layer security,how to construct the encoding scheme with low complexity and meet the safety and reliability become the focus of research has great practical significance in this model.In this paper,we first study the existing Ploar Code as the encryption code for the communication program,through the construction of the coding information bit selection changes,so that communication can meet the reliability and security.According to the existing schemes need to know the limitations of the main channel and wiretap channel channel state,this paper proposes using fountain codes encoding combined with polarization code,get enough information in the receiver when decoding a stop signal communication to minimize the eavesdropper can receive the.The combined scheme makes it possible to work properly even in the actual channel with time-varying and diversity.Subsequently,the safety encoding scheme in the erasure channel are extended to the additive Gauss channel more generally,while the amount of information on the reliability and leakage were analyzed and proved its security.The wiretap channel model requires that the quality of the eavesdropper must be worse than the main channel.This paper introduces the feedback structure,assuming there is a channel from receiver to the sender,through interactive communication,that even the wiretap channel is better than the quality of the main channel,secure communication can still reach.At the same time,we get the conditions of secure communication in different channels and the way to construct secure coding.