Well this isn't a normal key. It's a key with extremely reduced entropy for the sake of the puzzle. Most of the private key is already known and is in fact all zero.
So this would not be possible with a normal Bitcoin transaction with regular entropy.
Well, no, because "we" think it has half the entropy their length implies. This is widely known, and the length was selected with that information in mind.
Is that true for all of the future? I suppose it's only a matter of time before Satoshi's and all the lost wallets will be broken?
Even if it's 70 years from now before we have the compute to do that, the wallets will be worth so much by then that whoever does that will end up with a level of money that is high enough to menace and threaten entire countries if they are malicious.
Why doesn't Bitcoin require keys to get longer over time? Require 256 bit now but require 65536 bit in 20 years to make any transaction?
I think you underestimate how big the number of 2^128 ECDSA operations are. It is 20 orders of magnitude bigger than the puzzle that was just solved (that took 2 years). There is no way we scale our compute that much in 70 years unless we start building Dyson spheres.
To answer your question that change in bitcoin can happen at any point in time with a protocol update. It would probably won’t even require a hard fork, a soft fork would suffice.
> no way we scale our compute that much in 70 years
Huh? Ask someone in 1950 if we would ever achieve petaflops on a desktop-sized PC. Yet here we are with H100's. About 10 decimal orders of magnitude faster than the state of the art in 1950.
Quantum computing will also happen, and I think 70 years is more than a realistic time frame.
Because this is how the puzzle works. Most of the key bytes are zero. Only the last 66 had to be guessed. And their solution was made public by doing the payment.
So this would not be possible with a normal Bitcoin transaction with regular entropy.