Decentralizing 6G Security: Existing Challenges and Future Opportunities

6G communications networks will be highly decentralized and distributed in nature. Existing security policies, procedures, and technologies, however, are mostly based on centralized control. Such centralized security will have serious consequences from two perspectives in 6G. First, the security systems will not be able to meet the strict requirements, such as latency, of emerging services, for example industrial and vehicular communications. Second, centralized security will lead to high consumption of resources, such as spectrum, in securing distributed systems in 6G. Therefore, in this paper we discuss intriguing challenges arising from security centralization that lead to another pressing challenge of the time, i.e., sustainability, as a consequence. Furthermore, we evaluate centralized and decentralized artificial intelligence (AI)-based security to demonstrate the resource and efficiency trade-off. Ultimately, this paper presents important research insights and visions that can pave the way toward distributed security in 6G.