Research On Improvement Of Feistel Structure Based On Single Chip Microcomputer

With the rapid development of science and technology,computers are widely used.With the continuous progress of electronic information technology,there has been a computer used to complete a single task,that is,a single chip computer.Thanks to the low power consumption and simple structure design of the single chip computer,its cost is low and its size is small.On this basis,a variety of embedded devices have been widely used in industrial control,the Internet of Things,aerospace and other fields.It is also because of the structure of single-chip microcomputer and embedded equipment that it lacks good data protection capability.At the same time,the communication protocol is relatively simple and vulnerable to attacks from all aspects.Therefore,it is necessary to encrypt and protect the information it transmits.In addition,its operation capability is low and it can only use lightweight encryption algorithms.In order to solve the security problems of the single chip computer and embedded devices,this paper combines the characteristics of various encryption algorithms widely used today,selects the data encryption standard DES encryption algorithm suitable for hardware implementation to be applied to the single chip computer,and expands and improves this DES algorithm in order to achieve better encryption and decryption effects.This paper introduces the principle of the data encryption standard DES encryption algorithm,analyzes the nature of DES encryption algorithm,deeply understands the generalized Feistel structure by studying the widely used DES encryption algorithm and related improved algorithms,explores the encryption and decryption algorithm using the generalized Feistel structure on this basis,and puts forward a preliminary improvement scheme.After continuing to demonstrate,derive and expand the preliminary improvement scheme,an improved Feistel algorithm structure is proposed,which can be used not only on DES encryption algorithm,but also on other encryption algorithms with Feistel structure,such as IDEA,GOST and BLOWFISH.This improved Feistel algorithm structure not only increases the security of the original structure,but also has the matching feature in practical use,which makes the decryption algorithm and encryption algorithm completely consistent,and saves the process of redesigning and implementing the decryption algorithm.This paper further demonstrates the proposed improved Feistel structure from two aspects.The first aspect is to compare and analyze the data processed by the improved Feistel structure and the original structure,and choose the Python programming language to describe it.The f function in the two Feistel structures selects the encryption operation in DES.First,change the key several times to encrypt the text data,analyze the distribution of the ASCⅡ code of the ciphertext,change the text content to compare and analyze the encryption time,then select the "Lena" image commonly used in image analysis to analyze the information entropy of each channel of the ciphertext,and change the one bit key to study the pixel change rate of each channel of the encryption result,Further comparative analysis of encryption time was conducted by changing and increasing the size of plaintext,and it was found that the improved Feistel structure has better security and encryption efficiency than the original Feistel structure.The second aspect is to simulate the extended and improved Feistel structure on a microcontroller using Verilog HDL language.The running process is smooth,the encryption efficiency is good,and the verification of the extended and improved scheme is fully achieved.Through the above two aspects of argumentation,it is further inferred that the improved Feistel structure has the possibility and feasibility of safe use in microcontroller and embedded system encryption or communication encryption.At the end of this paper,the direction of further development and improvement of the improved Feistel structure is given,that is,it can be further extended to the structure of Feistel(n),and the structure and related characteristics of Feistel(n)are also briefly discussed.