Blockchain-Based Transparent Certificateless Data Integrity Auditing with Enhanced Tag Security

The integrity risks posed by data outsourcing in cloud storage have driven the development of remote data integrity auditing (RDIA) technologies. However, traditional schemes rely on trusted third-party auditors (TPAs), leading to potential collusion and single-point failure vulnerabilities. The integration of blockchain alleviates these issues through decentralization and transparency, yet existing blockchain-based certificateless auditing schemes still suffer from security flaws in the tag generation phase. Addressing the tag forgery vulnerability in Miao et al.’s scheme, which stems from the absence of random parameters in the hash function input, this paper proposes a lightweight enhancement mechanism: incorporating a random factor into the hash input during tag generation to ensure dynamic unforgeability of tags. While retaining the efficiency advantages of the original framework, the improved scheme achieves resistance against tag forgery, proof forgery, and collusion attacks under the Computational Diffie-Hellman (CDH) and Discrete Logarithm (DL) hardness assumptions, validated through rigorous formal proofs. Experimental performance analysis demonstrates that the proposed enhanced scheme introduces negligible computational overhead, providing a secure, practical, and transparent auditing solution for multi-cloud storage environments.