B5GRoam: A Zero Trust Framework for Secure and Efficient On-Chain B5G Roaming

2025-09-19

AI Summary

To address privacy leakage, strong trust assumptions, and scalability bottlenecks in existing blockchain-based roaming settlement schemes for 5G and beyond networks, this paper proposes a zero-trust on-chain reconciliation mechanism. The approach integrates non-interactive zero-knowledge proofs (zkSNARKs) with Layer-2 zk-Rollups to enable verifiable, on-chain roaming settlement without revealing user identities, locations, or network-specific details. Smart contracts enforce logical consistency, while zk-Rollups drastically improve throughput and reduce gas costs. Experimental evaluation demonstrates a throughput exceeding 7,200 transactions per second (TPS), achieving strong privacy guarantees, high efficiency, and decentralized trustworthiness. To the best of our knowledge, this work presents the first zero-trust architectural solution for cross-operator roaming settlement that simultaneously ensures practical deployability and rigorous security guarantees.

Technology Category

• Data Mining & Knowledge Management: Representing, Reasoning, and Using Provenance, Trust
• Planning, Routing, and Scheduling: Scheduling under Uncertainty
• Multiagent Systems: Mechanism Design

Application Category

• Security and Privacy: Blockchains and distributed ledgers
• Responsible Web: Data and user privacy-enhancing technologies for the Web
• Semantics and Knowledge: Provenance, trust, security and privacy, and ethical issues in managing semantic data

Abstract

Roaming settlement in 5G and beyond networks demands secure, efficient, and trustworthy mechanisms for billing reconciliation between mobile operators. While blockchain promises decentralization and auditability, existing solutions suffer from critical limitations-namely, data privacy risks, assumptions of mutual trust, and scalability bottlenecks. To address these challenges, we present B5GRoam, a novel on-chain and zero-trust framework for secure, privacy-preserving, and scalable roaming settlements. B5GRoam introduces a cryptographically verifiable call detail record (CDR) submission protocol, enabling smart contracts to authenticate usage claims without exposing sensitive data. To preserve privacy, we integrate non-interactive zero-knowledge proofs (zkSNARKs) that allow on-chain verification of roaming activity without revealing user or network details. To meet the high-throughput demands of 5G environments, B5GRoam leverages Layer 2 zk-Rollups, significantly reducing gas costs while maintaining the security guarantees of Layer 1. Experimental results demonstrate a throughput of over 7,200 tx/s with strong privacy and substantial cost savings. By eliminating intermediaries and enhancing verifiability, B5GRoam offers a practical and secure foundation for decentralized roaming in future mobile networks.

Problem

• Secure roaming settlement between mobile operators in 5G networks
• Privacy risks and scalability issues in blockchain-based solutions
• Need for trustworthy billing reconciliation without intermediaries

Innovation

• Cryptographically verifiable CDR submission protocol
• Non-interactive zero-knowledge proofs for privacy
• Layer 2 zk-Rollups for high throughput