Originally aired on July 19, 2023

The Looming Threat of Quantum Computers to Bitcoin and Blockchain

This episode explores the potential impact of advancing quantum computer technology on the future security of Bitcoin and blockchain. Quantum physicist Pierre-Luc Dallaire-Demers provides insight into how quantum computers work and why they pose a threat to current cryptography methods used in blockchain and finance.

While quantum computers are not faster in terms of processing speed, they enable calculations using the uncertain properties of subatomic particles that allow exponentially more computational complexity. This gives quantum machines the power to eventually break types of encryption previously thought secure, including the cryptographic signatures used in Bitcoin.

Dallaire-Demers explains the exponential growth in qubits and operations per second that quantum computers will achieve in the next 5-10 years. Though the timeline is debated, he warns Bitcoin’s signatures are among the easiest for quantum algorithms to crack. Upgrading blockchain cryptography will be challenging due to coordination difficulties in decentralized systems.

Dallaire-Demers advises cryptocurrencies must prepare now with “quantum-resistant” cryptography or risk losing user confidence as quantum supremacy draws nearer. He believes opportunities may arise for quantum-resistant coins if Bitcoin does not adapt. The episode concludes with a discussion of combining quantum computing with AI, and concerns over unknown advances taking place out of public view.

How do quantum computers differ from classical machines?

• Leverage quantum properties like particle uncertainty
• Allow exponentially more computational complexity
• Enable calculations impossible via classical means

Why does advancing quantum computing threaten blockchain security?

• Will break encryption previously thought computationally infeasible
• Includes signatures used to secure Bitcoin transactions
• Timeline to “quantum supremacy” over classical computers debated

What cryptographic risks do quantum computers pose to Bitcoin?

• Bitcoin signatures among easiest for quantum algorithms to crack
• Could reduce confidence even before attacks feasible
• Upgrading blockchain cryptography presents coordination challenges

What potential opportunities does quantum resistance offer?

• “Quantum-resistant” cryptographic coins could arise
• Chance for new projects if Bitcoin does not adapt cryptography
• But quantum-resistant upgrades advised for most chains

What concerns exist around unknown quantum progress?

• Quantum and AI may also combine in unforeseen ways
• Military may possess undisclosed advanced quantum capabilities
• True capabilities and timeline cannot be predicted