In this conversation, Stephan Livera and Jonas Nick discuss the implications of quantum computing on Bitcoin's security, focusing on the risks posed to cryptographic signatures. They explore the current vulnerabilities in Bitcoin, the potential for quantum attacks, and the need for post-quantum cryptographic solutions. The discussion covers various signature schemes, including hash-based signatures, their trade-offs, and the challenges of transitioning to a quantum-resistant Bitcoin. They also touch on the implications for hardware wallets, multi-signature schemes, and the potential need for block size increases to accommodate new signature sizes.

Takeaways:

🔸Quantum computers pose a real risk to Bitcoin's cryptography.

🔸Current Bitcoin signatures are vulnerable to long-range attacks.

🔸Hash-based signatures are significantly larger than current signatures.

🔸Transitioning to quantum resistance will require careful planning.

🔸The Bitcoin community must reach a consensus on new schemes.

🔸Verification costs will increase with new signature schemes.

🔸Hardware wallets will need to adapt to new signature requirements.

🔸Block size discussions may need to be revisited in light of quantum risks.

🔸The timeline for quantum computing advancements is uncertain.

🔸A gradual transition to quantum resistance may be necessary.

Timestamps:

(00:00) - Intro

(01:49) - How real is quantum risk to Bitcoin?

(04:39) - When could quantum pose a threat to Bitcoin’s cryptography?

(09:56) - Long range vs Short range attacks

(12:37) - How many coins are vulnerable to Long range attacks?

(14:12) - Different types of cryptography and exploring Hash-based signature schemes

(17:00) - Categories of Hash-based signature scheme and their pros & cons

(23:42) - How do Hash-based signatures work?

(32:14) - Would Lightning, Multi-sig, Taproot, Silent Payments, Atomic swaps work in a post-quantum world?

(38:50) - What are Adaptor signatures & how do they affect atomic swapping?

(41:27) - Will we need new Bitcoin hardware wallets?; Signature production & verification

(44:41) - Signature size and Bitcoin block capacity implications

(46:52) - Should we revisit the block size conversation?

(54:57) - Overview of SPHINCS+ & SHRINCS

(59:49) - Transitioning to post-quantum signature schemes; Overview of BIP 360

(1:09:06) - Closing thoughts

Links:

https://x.com/n1ckler

Stephan Livera links:

Hash-based signatures for Bitcoin's post-quantum future? with Jonas Nick | SLP713

Stephan Livera Podcast