Research On Fountain Code And Wireless Network Anti Eavesdropping Technology

With the continuous development of society,wireless transmission has become an important part of people's daily life.Due to the broadcast nature of wireless communications,the interception of data and malicious use may pose a great threat to wireless communications.Therefore,wireless communications security has become especially important.However,the traditional wireless secure communication schemes mostly realize the information protection and secure transmission by increasing the redundancy by encrypting the shared keys among the legitimate communicators.Once the secret key is leaked or deciphered,it will be generated Huge loss.How to ensure the safety of the transmission of these information has become a research focus of researchers.This thesis first proposed the use of fountain code as anti-eavesdropping code to ensure the safe,effective and reliable transmission of information.Because fountain code has the characteristics of small decoding cost,simple coding and decoding method and low complexity,as a channel coding of wireless communication,fountain code can effectively improve the validity and reliability of wireless transmission.The coding method is that the source randomly selects a certain number of symbols according to the probability distribution to obtain the encoded symbols by EOR.After receiving enough encoded symbols to recover the source message,the source stops sending the encoded symbols.In wireless communication,the error signal generated due to noise is random.Different channel noise in the same source broadcast information will cause different receiving end to receive the correct information symbol.The fountain code is used to prevent eavesdropping on the channel.When the receiver recovers the source symbol,there is a situation that the legitimate receiver ends the decoding before the eavesdropper,causing the eavesdropper to generate a BER and unable to recover the source information.In order to further improve the BER of the eavesdropper,this thesis sends the random code used for encryption at the legitimate receiver and at the same time adds artificial noise,forcing the eavesdropper to open the channel with the legitimate receiver,causing the eavesdropper to receive the information transmission The error rate is greater than the error rate of information transmission between the main channels,which greatly increases the BER of the eavesdroppers receiving the information and ensures the safe transmission of the information of the legitimate receivers.The experimental results show that the scheme proposed in this thesis can increase the BER of the eavesdropper while ensuring that the legitimate receiver receives the message.In particular,adding a small amount of artificial noise can greatly increase the BER of the eavesdropper,BER can be 40% or more,can achieve the purpose of anti-eavesdropping.Therefore,the combination of fountain code and artificial noise is used in wireless transmission,which can not only ensure the reliable and efficient transmission of information,but also prevent the eavesdropper from disclosing the information due to deciphering or stealing the key,ensuring the information transmission Security.