Secure 6G Distributed Group Authentication and Key Agreement via Sharding Blockchain

The sixth-generation (6G) network is the core technology of next-generation communication, providing high-quality, low-latency, and broad connectivity communication services for the digitalization and intelligent transformation of future society. The large-scale, low-latency access demands of 6G devices place higher requirements on authentication services. Traditional authentication and key agreement (AKA) schemes rely on a single home network (HN) server for authentication, making the system vulnerable to security and availability issues if the server experiences a crash or is attacked. Moreover, the limited performance cannot meet the authentication throughput demands of 6G. Therefore, this paper presents the first 6G distributed group authentication scheme, called 6G DGAKA. The scheme is mainly based on the Byzantine Fault Tolerance (BFT) protocol and sharding blockchain to achieve group AKA. Firstly, multiple HN servers form an HN committee, which runs BFT to handle authentication requests, ensuring consistency, liveness, and fault tolerance. Secondly, as the system user number increases, we enhance system throughput and scalability by adding more HN committees as multiple parallel shards to process authentication requests. Thirdly, we design a 6G group authentication protocol to achieve efficient batch authentication of multiple devices, while also enabling mutual authentication among devices within the group and preventing malicious behavior from group leaders. Fourthly, we conduct implementation and evaluation, demonstrating that 6G DGAKA offers excellent forward compatibility, high throughput, low latency, and scalability.