Simulating Quantum Threats to Web3 Cryptographic Primitives using Qiskit

Abstract

Web3 technologies are fundamentally secured by classical cryptographic algorithms like the Elliptic Curve Digital Signature Algorithm (ECDSA), Advanced Encryption Standard (AES), and Secure Hash Algorithms (SHA). The advent of fault-tolerant quantum computers, however, poses a significant threat to these systems. Shor’s algorithm can break the asymmetric schemes that underpin user wallets and asset ownership, while Grover’s algorithm quadratically weakens the security of symmetric ciphers and hash functions. This paper presents an integrated simulation framework, built using Python and Qiskit, to demonstrate these quantum threats in a unified context. We implement simulated attacks against simplified, small-scale instances of RSA, ECDSA, AES, and SHA to model the structural feasibility of these quantum attacks. For Shor’s algorithm, we utilize a classical simulation of the quantum oracles for modular exponentiation and elliptic curve point addition, focusing on the viability of the overall quantum-classical workflow. For Grover’s algorithm, we use standard Qiskit circuit library implementations with simplified oracles. Our findings confirm the theoretical vulnerabilities—successfully factoring RSA-15, solving the ECDLP on a toy curve, and finding keys/preimages in 8-bit search spaces. More importantly, this work highlights the practical simulation challenges and immense resource requirements for breaking production-scale keys, reinforcing the critical need for the Web3 ecosystem to transition towards post-quantum cryptography.