Re:MicroStrategy buys BTC with abandon, Tether hits $20B, Ma...
by gruez on Monday December 14, 2020 @02:00PM
(#25421638)
> Once we achieve quantum supremacy, is it still impossibly hard to break the private keys?
Yes, because there are mitigations in place (since day one I believe). When you send bitcoin to an address, you don't send to a public key, you send to a hash of a public key. It's only when you need to spend the coins that you need to disclose the public key. According to wikipedia hash functions are considered safe against attacks against quantum computers[1] so any coins stored in addresses that haven't been spent from before should be safe. There's still potentially a window of vulnerability between when a transaction is broadcast and when it's confirmed, but I doubt quantum computers offer enough of a speed-up that it can crack a 256 bit secp256k1 key within an hour or two.
Yes, because there are mitigations in place (since day one I believe). When you send bitcoin to an address, you don't send to a public key, you send to a hash of a public key. It's only when you need to spend the coins that you need to disclose the public key. According to wikipedia hash functions are considered safe against attacks against quantum computers[1] so any coins stored in addresses that haven't been spent from before should be safe. There's still potentially a window of vulnerability between when a transaction is broadcast and when it's confirmed, but I doubt quantum computers offer enough of a speed-up that it can crack a 256 bit secp256k1 key within an hour or two.
[1] https://en.wikipedia.org/wiki/Post-quantum_cryptography