A Post Quantum Migration Proposal

The discussion opens with Antoine Riard expressing skepticism about the necessity and practicality of integrating post-quantum cryptography (PQC) into Bitcoin, especially given its significant performance drawbacks compared to Elliptic Curve Cryptography (ECC). Riard points out that unless PQC is deemed absolutely necessary due to tangible risks, its implementation could be more harmful than beneficial. This stance is rooted in the belief that switching to PQC should only occur if the potential threats from quantum computing to ECC become undeniable and pose an existential risk to the system.

The conversation acknowledges the existence of risks associated with cryptographically relevant quantum computers (CRQCs), but Riard suggests that any move towards PQC would be premature until there's a widespread consensus within the community that these risks are real and imminent. The emphasis is on the hope that, should this consensus ever be reached, it will still allow sufficient time for the ecosystem to adapt and safeguard itself against quantum vulnerabilities.

Riard also clarifies a technical point regarding what constitutes a quantum-vulnerable Unspent Transaction Output (UTXO). He defines any UTXO not protected by an agreed-upon PWC scheme as vulnerable, indicating that both long and short-range attacks by quantum computers could potentially compromise these assets. This part of the discussion underscores the broader implications of quantum computing on the security framework of digital currencies like Bitcoin, highlighting the need for a cautious yet proactive approach in considering transitions to new cryptographic standards.