Quantum computers threaten the public-key cryptography that secures blockchain accounts and transactions. Charles Hoskinson has warned that moving blockchains to post-quantum algorithms could reduce throughput by roughly tenfold. NIST is leading the standardization of quantum-resistant algorithms, but technical and governance trade-offs mean the path forward will be slow and strategic.
The Future of Quantum Threats and Mitigation Costs
The primary near-term quantum risk is Shor style attacks capable of breaking ECDSA and RSA signatures used by Bitcoin, Ethereum and many other networks. Agencies such as DARPA have suggested practical, large-scale quantum machines could appear by 2033. Mitigations involve algorithms that use heavier arithmetic, larger keys and bigger signatures. That translates to higher bandwidth, larger blocks or smaller effective throughput and more CPU work for nodes and validators. Charles Hoskinson’s tenfold estimate captures the reality that post-quantum verification and signing are materially more expensive than today’s elliptic-curve operations.
Two Paths to Post-Quantum Security
Broadly there are two practical approaches. Hash-based cryptography relies on hash functions to build one-time or few-time signatures. It is conceptually simple, conservative in assumptions, and attractive for signature-only use cases favored by parts of the Ethereum community. Lattice-based cryptography provides both signatures and encryption and underpins NIST selections such as CRYSTALS-Kyber and CRYSTALS-Dilithium. Cardano and other projects have signaled interest in lattice approaches. Lattice schemes can be more feature-complete and may perform well on parallel and matrix-friendly hardware used in AI accelerators.
The Challenge of Blockchain Migration
Migrating decentralized networks is not a single software update. It requires consensus across node operators, wallets and exchanges, coordinated address migration or fund transfers, and handling keys stored in cold wallets. Bitcoin’s conservative governance and globally distributed user base make a rapid migration unlikely. Any migration must also protect legacy on-chain data and ensure that historical public keys do not expose funds once powerful quantum machines exist.
Preparing for What’s Next
The quantum threat to blockchains is plausible on a multi-year horizon. Practical steps include following NIST standards, testing hybrid signatures, rolling out opt-in quantum-safe addresses, and funding research into efficient implementations. With careful planning and staged upgrades, blockchains can manage the performance trade-offs while protecting long-term value.
