Changes to BIP-360 - Pay to Quantum Resistant Hash (P2QRH)

It highlights the potential for a Cryptographically Relevant Quantum Computer (CRQC) to compromise elliptic curve cryptography, which underpins Bitcoin's security. The discourse suggests that breakthroughs in quantum computing could allow attackers to break EC public keys, posing a significant threat to the security and value of Bitcoin. To address this, two scenarios are considered: one where an attacker requires a week to compromise an EC public key, with the attack duration halving every two months, and another more dire situation where an EC public key can be broken in just one second. The discussions propose moving assets from P2TR coins to P2SH addresses as a protective measure and suggest soft or hard forks to disable vulnerable outputs or key spends, enhancing Bitcoin's security against such attacks.

Further elaboration on the topic introduces the P2QRH protocol as a method for enabling quantum-secure transactions while also utilizing Schnorr signatures to mitigate high transaction fees. However, concerns are raised about the effectiveness of this measure in the face of a CRQC emergence, suggesting that a comprehensive move to disable all EC spending is necessary for genuine security. Additionally, the importance of transitioning to quantum-resistant solutions like P2QRH and PQ signature opcodes is underscored, despite potential challenges in adoption due to increased transaction fees and hesitance from wallets and exchanges to support new, costly output types.

The dialogue also touches upon user experience (UX) and developer experience (DX) issues related to transitioning Bitcoin towards quantum resistance, emphasizing the need for clear differentiation between quantum-vulnerable and quantum-resistant addresses to avoid confusion among users. The suggestion to temporarily disable EC opcodes until a robust quantum-resistant solution is adopted reflects the complexity of ensuring Bitcoin's security in anticipation of quantum computing advancements.

In terms of community involvement and the development process, the conversation reveals efforts to enhance Bitcoin's scripting capabilities through BIP drafting and the critique of existing proposals based on their effectiveness in protecting against quantum threats. The critical analysis suggests that disabling key-path spending on P2TR addresses and focusing on script endorsements could offer a path toward securing Bitcoin transactions against future quantum computing threats.

Lastly, the technical discussions explore the feasibility of implementing post-quantum cryptographic methods within Bitcoin, suggesting renaming and conceptual adjustments to proposals aimed at introducing quantum resistance into the network. This includes reconsidering the nomenclature to better communicate the security features of different outputs and the proposal to transition Pay to Quantum Resistant Hash (P2QRH) to a script-only version of Taproot (P2TR), enhancing protection against quantum attacks while leveraging existing infrastructure for easier integration and understanding.