Encryption And Decryption Technology In Fy-iii Weather Satellite Data Transmission

As the second generation of polar-orbit meteorological satellite in China, FY-3 will ready to introduce encryption-decryption technique in Middle resolution spectrum Picture Transmission(MPT) for MPT data used in special conditions only by those who are authorized. To confirm the feasibility of encryption-decryption manipulation and fulfill the needs of receive system on the ground, the process of encrypting-decrypting data should be realized and the data-processing system should be designed and realized.They all base on the principle and algorithm of encryption-decryption.This paper first researches the principle of encryption-decryption and the basic algorithm-Data Encryption Standard(DES). Then analyzing based on the format of data transmission, encryption-decryption basic algorithm and work mode, algorithm is realized by software. Since the realization of algorithm according to individual analysis and understand, it is valided by simulated data before encryption and after encryption that are created by the system of data transmisson in satellite.The realization of kernel algorithm is proved to be right. Then to fulfill the requirement of speed of data process, algorithm is improved based on validity of realization. The speed of data process is obviously increased.The integrity of encryption-decryption system needs key-management, so some functions of key-management are designed and realized. The security of keys is strengthen. Finally, software system is be designed and realized that is used to decrypt data in receive system on the ground.Depending on realization of the kernal algorithm and key-management, the requirement of decryption is finally fulfilled in receive system on the ground.At the end of this paper, basic algorithm is analysed that is applied to American NPOESS satellite.Then compare it with basic algorithm.that is applied to Chinese FY-3 satellite. Find that DES has not advantage of security and efficiency.Through the results of research and analysis,we know that MPT transmission data can be processed depending on DES algorithm and work mode;The security of keys can be man-made strengthened according to key-management;The design and realization of software system can fulfill the requirement of decryption in receive system on the ground.