The Study Of Encryption Mechanism In Digital Trunking Communication System

Recent years, with the rapid development of communication, the research of digital trunked radio communication system becomes more and more important. Digital trunking communication system is mainly used in police, government, national security section and so on. These applications need transmission large amount of secret information, and have high security demand. So the security aspect is absolutely necessary in the whole system architecture to make sure the system's function safely. The digital trunking communication system has a late initial step in our country. Most of them are introduced from abroad. For most of the encryption algorithm is kept secret, it is difficult to know whether it is perfect or not. So the study of encryption mechanism in digital trunking communication system is most significant to the construction and development of digital trunking communication system in our country.The main research part of this thesis is the study of encryption mechanism in digital trunking communication system. Firstly, the security and secrecy mechanism is introduced, including the one-way and two-way authentication process, the encryption process of air interface, the secret key selection and management and the end-to-end encryption process. The end-to-end encryption process is explained as the most important aspects. Secondly, some encryption algorithms are introduced, with the analysis and comparison for these encryption algorithms, the author designs an appropriate project to accomplish the end-to-end encryption. Thirdly, this paper accomplish the design of an encryption scheme which combining the strongpoint of the RSA algorithm and the IDEA algorithm. The main process is as following: first, input the digital signal to the encryption device, and then the digital signal exclusive or with the keying sequence which is generated by key stream generator (KSG) and the KSG is based on the IDEA encrypting and deciphering algorithm, the secret key synchronization is also studied. The IDEA key is encrypted and deciphered with RSA algorithm. In order to obtain high encode/decode rate, the basic algorithms are deeply optimized. So the processing speed and efficiency of RSA algorithm...