Yes, post-quantum cryptocurrency can be built using Lamport signatures or, I think more likely, a full-fledged post-quantum public key system. But would such a hard fork still be “bitcoin”? Will there be enough coordination to make the jump? Why bet on it? Added: in other words, you have now switched to an argument of the form: this community will respect property rights, which is exactly opposite to the technical argument you started with.
Also, it’s not just about Shor’s algorithm. Grover’s algorithm is a big deal. The advent of quantum computers will dramatically concentrate the pool of hashing power into few hands. I’m not sure what will happen, but I think that there is a good chance that the value of existing cryptocoins will be wiped out, even though the technology will be resurrected after quantum computers become widespread.
Quantum computers actually will not kill bitcoin. It’ll take a significant coordination, but it’ll survive:
https://bitcoinmagazine.com/6021/bitcoin-is-not-quantum-safe-and-how-we-can-fix/
Now, P = NP will kill bitcoin. But I rate that risk as being much lower than scifi gold mining techniques.
Yes, post-quantum cryptocurrency can be built using Lamport signatures or, I think more likely, a full-fledged post-quantum public key system. But would such a hard fork still be “bitcoin”? Will there be enough coordination to make the jump? Why bet on it? Added: in other words, you have now switched to an argument of the form: this community will respect property rights, which is exactly opposite to the technical argument you started with.
Also, it’s not just about Shor’s algorithm. Grover’s algorithm is a big deal. The advent of quantum computers will dramatically concentrate the pool of hashing power into few hands. I’m not sure what will happen, but I think that there is a good chance that the value of existing cryptocoins will be wiped out, even though the technology will be resurrected after quantum computers become widespread.