Design Of Feedback Encoding Scheme For Biometric Authentication System Based On Bernoulli Noise

With the rapid development of the information age,the issue of information security has attracted more and more attention.How to carry out reliable identification and ensure the security of users' information has always been an urgent issue in the information age.Traditional authentication methods,such as passwords and physical tokens,are insufficient to combat identity theft or ensure security.The proxy representation of this identity can easily be forgotten,lost,guessed,stolen,or copied.The increasing demand for more reliable and convenient security systems makes people interested in biometric authentication technology.From the perspective of information theory,the fuzzy commitment scheme in biometric authentication system is studied in this thesis,namely J-W scheme.Since the results of two measurements of the same biometric characteristics are rarely identical,encoding is required in the J-W scheme to obtain the original biometric through error correction decoding.According to previous work,the J-W scheme can be equivalent to wiretap channel model and the maximum transmission rate of secure under this model is given.In this model,if the wiretap channel is more capable than the main channel,the secrecy capacity of the channel will be equal to zero.In order to solve this problem,the idea of channel feedback is introduced into the equivalent model of the J-W scheme based on Bernoulli noise,a binary symmetric wiretap channel model with feedback is given,and the secrecy capacity of the improved equivalent model is given.The results show that feedback can increase the secrecy capacity of the system and improve the coding efficiency of the J-W scheme.For the improved equivalent model of the J-W scheme,key-based coding scheme with feedback is used,which uses the feedback message to generate a secret key to encrypt the original message,and the key is only shared among legitimate users.The theoretical and simulation analysis show that even if the wiretap channel is more capable than the main channel,secure communication can be realized.At the same time,compared with the original scheme,the secrecy capacity is increased,that is,the coding efficiency of J-W scheme is improved.In addition,for the improved equivalent model of the J-W scheme,a new coding scheme with feedback-the SK-like scheme,is proposed in this thesis,and the specific coding scheme is given.In SK-like scheme,we divide code words into blocks,the original message only participates in the coding in the first block,and the other blocks send only the channel noise obtained by feedback.Compared with the key-based feedback scheme,although there is information leakage,the complexity of encoding and decoding is reduced,the decoding efficiency is improved,and the transmission rate will not be lost,that is,the maximum coding efficiency of the J-W scheme can be achieved.