Research And Design Of Digital Media File Encryption System Based On Chaotic System

With the rapid development of computer technology,people pay more and more attention to issues such as information security.Because the transmission of information mainly uses two kinds of media files types:text and image as the carrier,and encryption and decryption technology as an effective file protection method.Therefore,it is very important to use the encryption algorithm to encrypt and decrypt these two kinds of media files.Traditional encryption algorithms cannot be well balanced in terms of security and encryption speed,and chaotic systems are widely used in cryptography due to their initial sensitivity and pseudo-randomness.In this context,this paper proposes a chaotic system-based encryption and decryption algorithm for text and image file types.The main research contents are as follows:A text media file encryption algorithm based on chaotic system and AES is proposed for text file types.The original AES key expansion algorithm is improved by using a Logistic chaotic map to obtain a round key sequence,and then XOR with another chaotic sequence generated by Logistic chaotic map to obtain the final extended key.Then,Chebyshev chaotic map is used to dynamically generate the S-box,and the Arnold chaotic system is used to scramble the S-box to construct the S-box in the AES algorithm.The proposed algorithm not only greatly expands in the key space,but also overcomes the shortcomings of the traditional AES algorithm using a fixed S-box and can not effectively resist plaintext attacks.At the same time,the algorithm also guarantees the security and efficiency of encryption.A digital media file encryption algorithm based on multi-chaotic system is proposed for image file types.Firstly,the original image is scrambled and diffused on the row and column by Chebyshev chaotic sequence to obtain the intermediate encrypted image.Then,the chaotic sequence generated by the Lorenz chaotic system is sorted and digitized in order to obtain the gray matrix and the position matrix.The intermediate encrypted image is encrypted by using the two matrices to obtain a final encrypted image.The proposed algorithm performs scrambling and spreading operations at the same time,which can effectively shorten the encryption time.In addition,combining multiple chaotic systems can effectively improve the security of the encryption algorithm.Simulation experiments and security analysis show that the proposed algorithm has good security and encryption effect on image encryption.Based on the above two encryption algorithms,a digital media file encryption system based on chaotic system is designed and implemented.In-depth study of the system architecture,the system is divided into three aspects:algorithm layer,interface layer and application layer.Then,the system is designed as a whole and divided into functional modules.Finally,the system is implemented by C#,and the system test is carried out to verify the correctness and feasibility of the system.The system mainly realizes the functions of file encryption and decryption and encrypted file viewing,thereby protecting the digital media files.