The integration of 6G networks with emerging key technologies such as
blockchain, artificial intelligence, and digital twins continues to improve.
However, it carries many issues with security threats and challenges of 6G
networks. In this article, we analyzed the security issues of 6G networks
and presented some possible solutions. First, we discussed the developments
of mobile communication technology, the research motivation of 6G networks,
the comparison of Key Performance Indicators (KPIs) between 5G/6G networks,
and the key technologies of 6G networks. Next, security threats in the 6G
network were analyzed concerning architecture, major visions and related
applications. This was followed by solutions to security issues in applying
key technologies for 6G networks. We also presented the application of AI in
solving 6G network security problems. Firstly, we illustrated the impact of
AI on 6G networks from two aspects: AI promotes the construction of 6G
networks, and AI brings security threats to 6G networks. Then, we
demonstrated that AI can assist 6G networks in solving security problems in
many ways. Lastly, the is summarized, and the future directions in this area
are proposed.