Oddbean

Bitcoin is already relatively quantum proof (current quantum computers can’t crack it). This fud has been going around for years and still nobody has been able to get close. Most legitimate cryptographers in this field don’t see this being a threat for at least 10-30 years.

I guess 30 years is some breathing room, but 10 years, being just 2.5 halving cycles away, would be close enough I’d say it’s time to test candidate algorithms. Especially if there’s a significant chance 10 years is pessimistic.

Bitcoin wallet quantum insecurity would keep bitcoin from being long-term deflationary as only coins that migrate to quantum secure wallets will be safe (if current wallet specs are proven quantum insecure). There will be 21,000,000 bitcoin after all.

There will be 20,999,999.99 coins regardless of Quantum vs non-quantum I disagree entirely. When we moved to new addresses when we softforked to segwit or taproot this didnt create more bitcoin it just required people to move their coins to a new address format for security or capability reasons if they so choosed. If a computer is one day able to guess a private key (more private key options than stars and planets in the known universe) then this would just result in stolen coin. There is no creation of new bitcoin in this process.

I didn't say new bitcoin. 'Lost key' coins are currently out of circulation. Degradation of prior encryption standards by quantum computing would lead to those coins returning to circulation (through network compliant transactions) and would return the "in circulation" total to nearer 21,000,000. Key holders own the coins. They are not stolen if another person can reasonably calculate the private key; e.g. low entropy dice or brain wallets getting spent. For this reason, I wouldn't time lock coins for added security to dates where I consider quantum computing to be a concern.