ZTP: A Scalable and Lightweight Privacy-Preserving Blockchain via Scale-Free Quorums and Geometric Fragmentation

Ensuring data privacy in blockchain systems remains challenging due to the heavy computational and communication costs of traditional cryptographic mechanisms. Existing solutions often suffer from limited scalability, high resource consumption, and inefficient tamper-proof key management. To address these challenges, we propose Zero Trust Privacy (ZTP), a lightweight framework for scalable on-chain privacy and secure distributed key management. ZTP introduces a hybrid quorum protocol using dynamic scale-free graph adjustments and a parallel data and key management mechanism based on the Geometric Fragmentation Technique (GFT), achieving efficient, tamper-resistant shard handling. To further enhance scalability, we incorporate a lightweight consensus protocol with parallel transaction processing, isolating transactions and key access from untrusted blockchain nodes. We implement and evaluate ZTP on a distributed blockchain prototype, demonstrating outstanding performance, achieving up to 49% fault tolerance, and delivering speedups of at least 55 × compared to state-of-the-art blockchain protocols. Our results highlight ZTP's potential for resource-constrained and large-scale blockchain deployments.