NxGenT: A decentralized trust system for B5G and 6G networks based on blockchain and smart contracts

The submitted work contains the following highlights: • We detail NxGenT, a decentralized reputation system for B5G and 6G networks. • We propose a three-phase reputation mechanism based on smart contracts. • We implement NxGenT and release its source code as open-source software. • We analyze NxGenT’s design and resilience against relevant trust attacks. • We evaluate NxGenT’s functionality and performance through experimental analysis. The evolution towards Beyond 5G (B5G) and 6G networks presents highly heterogeneous and dynamic scenarios in which numerous entities, including network operators, service providers and end users, interact in environments of mutual trust. However, the open nature of these networks poses significant challenges regarding security and trust, as traditional centralized mechanisms may prove inadequate or insufficient in such scenarios. In this context, decentralized trust systems are positioned as a promising solution to assess the reliability of entities participating in B5G and 6G networks, thereby enhancing decision-making processes and resilience of these environments. This paper introduces NxGenT , a decentralized reputation system based on blockchain and smart contracts for B5G/6G networks that guarantees the immutability and transparency of the collected evidence on entities’ performance and behavior, while decentralizing and automating the reputation mechanism. NxGenT is a decentralized, trustless system in which entities establish and verify compliance with Service Level Agreements (SLA) and provide feedback or subjective opinions about the entities they interact with in order to compute and assign reputation scores. To evaluate the proposal, we implement a local B5G testbed that deploys the primary components of this type of network, along with a second cloud-based testbed to analyze scalability in networks of different sizes. Finally, we contextualize NxGenT within the 6GENABLERS project as a representative use case of the proposed trust system, thus demonstrating its applicability in real scenarios.