PQC - What is our Goal, Even?

The recent discussions on post-quantum cryptography (PQC) in the Bitcoin community highlight divergent fundamental goals among participants, often leading to ineffective communication. The primary objective should be to enhance the security of Bitcoin against potential threats posed by quantum computing. This involves ensuring that a larger number of coins are securely protected by the time cryptographically relevant quantum computers (CRQC) come into existence. By minimizing the risk of theft, the need for drastic measures such as forking Bitcoin to burn vulnerable coins could be reduced.

Focus needs to shift towards wallets that are least likely to migrate to safer cryptographic practices on their own. These typically include popular wallets listed in app stores such as Bitcoin.com, Trust Wallet, Coinbase Wallet, and Blockchain.com. Such wallets often use static addresses to simplify user experience but at the cost of neglecting robust security upgrades, particularly those necessary for countering future quantum threats. Prioritizing these widely-used wallets can significantly decrease the total number of vulnerable coins, thereby reducing the likelihood of needing community-driven extreme solutions like coin burning.

While it is tempting to aim for the most advanced post-quantum security solutions or to perfect the design of future signature schemes for Bitcoin, these are not immediate priorities. The practical approach does not involve focusing on high-security setups that only benefit a small portion of users or trying to predict the optimal design for a post-CRQC scenario. More pressing is the requirement to safeguard the existing infrastructure and user base. Discussions about adjustments such as witness discounts or increased block sizes to handle larger transaction sizes due to new cryptographic methods are also deemed premature at this stage.