Security Analysis and Performance Evaluation of Certificateless Proxy Re-Encryption for Blockchain Applications

Certificateless Proxy Re-Encryption (CL-PRE) eliminates certificate management and private key exposure risks for blockchain data sharing, but existing schemes have critical security vulnerabilities and performance limitations. This research work presents comprehensive security analysis and performance evaluation of CL-PRE schemes for blockchain applications. The primary contribution is discovering a critical public key replacement attack against Wang et al.’s CL-PRE scheme, where Type I adversaries completely compromise message confidentiality by substituting legitimate public keys with adversary-controlled keys, enabling ciphertext decryption without private keys and violating IND-CCA security. The systematic performance evaluation of pairing-free PRE schemes for blockchain environments is conducted through extensive benchmarking of three schemes implemented in Go. Results show self PRE achieves superior security but incurs 13.7% higher execution time than certificateless schemes. To address vulnerabilities, this work proposes a secure CL-PRE framework with enhanced validation mechanisms. The Ethereum implementation reduces on-chain storage by 40% while maintaining provable security. The framework achieves 14.1% better performance than existing secure schemes and reduces gas costs by 14.3%. These findings establish security benchmarks and practical guidelines for blockchain developers, emphasizing rigorous cryptographic analysis importance for decentralized access control advancement.