Post-Quantum commit / reveal Fawkescoin variant as a soft fork

The email exchanges on the Bitcoin Development Mailing List have sparked a debate regarding the implementation of a commit/reveal protocol to safeguard Bitcoin transactions against potential quantum computer threats. The proposed system is specifically designed for instances where wallets, inactive for an extended period, are suddenly exposed to the vulnerabilities posed by quantum computing advancements. This system would enable such wallets to execute a one-time "commitment transaction" followed by a "reveal transaction," effectively transferring their funds to a new, quantum-resistant script. The intention behind this proposal is not to overhaul the current method of transferring BTC but to offer a failsafe for users caught unprepared by quantum computing capabilities.

The discussions also touch upon the feasibility of implementing this protocol without necessitating the acquisition of new BTC through out-of-band purchases for the majority of users. It suggests that users could utilize a small pre-quantum UTXO, which would be economically impractical for a quantum attacker to exploit, to create the required commitment. This approach would circumvent the need for purchasing new BTC, except in cases where users possess only high-value pre-quantum UTXOs and lack smaller denominations for making the commitment. In such scenarios, acquiring a new, minor UTXO out-of-band would become necessary.

These deliberations underscore the community's effort to proactively address the looming threat of quantum computing to Bitcoin's security. By considering both the technical feasibility and economic implications of such a protocol, contributors aim to ensure the longevity and resilience of Bitcoin in the face of evolving technological challenges.