基于北斗空时信息的安全通信方法

随着5G大规模商用和6G研发的启动，天地一体已成为未来移动通信发展的共识，然而空口边界被无限扩大，使无线通信安全面临着前所未有的严峻挑战，我国北斗三号卫星导航系统的全球位置信息服务为安全通信与定位导航的学科交叉提供了可能。提出了一种利用用户空时信息进行加密的安全通信方法，该方法是一种利用位置和时间唯一性的加密技术，通过北斗卫星导航系统的定位授时服务获取用户的空时信息，基于短报文业务实现信息共享，在传统加密算法的基础上提供额外安全层。该方法在密钥生成阶段提出了一种基于MD5信息摘要结合Logistic混沌映射的密钥生成算法（MD5-Logistic），使加密过程随位置变化而动态更新。仿真结果表明，该算法生成的密钥具有较高随机性，且有效降低了生成密文与明文间的相关性。在此基础上，为提升对定位误差的容忍能力，引入容忍距离概念，将解密范围从一点扩大为一个区域，使系统的鲁棒性及实用性得到显著提升。最后通过实测得到通信成功率与容忍距离间的关系，并给出合适的容忍距离。

A Secure Communication Method Based on BeiDou's Space Time Information

With large-scale commercialization of 5G and research development of 6G, the integration of space and earth has become the consensus for the development of future mobile communications. However, the air interface boundary has been infinitely expanded, exposing wireless communications security to unprecedented challenges. BeiDou-3 Navigation Satellite System''s global location information service makes the cross-discipline of safety communication, positioning and navigation possible. This article proposes a secure communication method that makes use of users'' space-time information for encryption. This method is an encryption technology that uses the uniqueness of location and time to obtain user''s space-time information through the positioning and timing service of the BeiDou-3 Navigation Satellite System. The method achieves information sharing through short message service, and provides an extra layer of security on the basis of traditional encryption algorithms. A MD5-Logistic chaotic mapping key generation algorithm is proposed, and the encryption process is dynamically updated with position changes. The simulation results show that the key generated by the proposed algorithm possesses high randomness and effectively reduces the correlation between the generated ciphertext and the plaintext. In order to reduce the huge overhead caused by frequent short message communication, the concept of tolerance distance is introduced, and decryption is expanded from one point to an area, so as to improve tolerance to positioning errors and significantly improve the robustness and practicability of the system. Through actual measurement, the relationship between the communication success rate and the tolerance distance is obtained, and suitable tolerance distance is given.