Hybrid Post-Quantum Cryptography and Ethereum Signatures: A Comprehensive Performance Benchmarking Study

The emergence of Quantum computing has threatened the Elliptic Curve Cryptography (ECC) used by blockchains such as Ethereum. In this paper, we provide a performance benchmarking of a hybrid signature architecture combining Ethereum's built-in ECDSA with NIST-standardized post-quantum cryptography (PQC) signature algorithms. We examine and compare seven PQC algorithms; CRYSTALS-Dilithium, FALCON, and SPHINCS+ across different security levels by integrating PQC signatures into transaction data while preserving ECDSA for transaction authentication. We provide metrics such as key generation, blockchain gas prices, key and signature sizes, and signing and verification in our analysis. The experiments demonstrate key generation times between \SI{8.78}{\milli\second} and \SI{133.60}{\milli\second}, signature timings between \SI{6.14}{\milli\second} and \SI{1675.18}{\milli\second}, and verification times between \SI{2.82}{\milli\second} and \SI{8.29}{\milli\second} is acceptable overhead as compared to ECDSA. The hybrid approach provides a workable and backward-compatible migration path toward quantum-resistant blockchain systems, despite the fact that PQC keys and signatures are significantly larger, they require about 87K and 1,740K gas units for PQC key registration, which is two to eighty-seven times more expensive than standard ECDSA transactions. Finally, we draw attention to the trade-offs in hybrid PQC blockchain systems between cost, security, and performance.