Hopefully if Bitcoin is still around when a new computing technology is emerging that truly threatens the security of the SHA256 hashing we do now, we can rally enough support to get a mainline fork like P2SH to switch to a more secured hashing system for future blocks. The hashing algorithm CAN be changed, even in the main Bitcoin chain, if the devs and the miners can all agree that the change is necessary for the currency to continue.
If a quantum computer can fullfill the function of bitcoin mining, and accomplishes it far more rapidly than current technology, would this not impact the dynamics of how bitcoin operates in terms of economics?
There are a few academic papers in circulation that point to a possible early prototype of a quantum computer within 2020s to 2030s. Despite the pace of our understanding picking up in this type of computing, there is still a long way to go before they become commercialized to the general public.
So far we just reached the 22 nm node for integrated circuits, it is predicted by 2015 we will hit 15 nm. Quantum Tunneling is predicted to be an issue below this node, some academicians this year proved otherwise, indicating Ohm's law still functions below 15 nm. Maybe the design/approach to computing might be rethought as we shrink further before reaching quantum computers, such as going from an incandescent light bulb to a LED bulb.
I'm certainly not worried about this happening unexpectedly. The bitcoin community is very involved in technology, and I'm sure if something appeared on the horizon as a game-changer, the forums would light up much faster than that technology became available. If the technology improves steadily and we just see continual hash rate growth, it's no issue. The only time I would see a "threat" is if some new technology appears that is hard to obtain, yet able to either break sha256 or at the very least trivialize the current brute forcing of it. Quantum computing has often been mentioned as a potential threat in this way, though I don't know if there is much validity in that concern.
I agree, I think the forums would light up a great deal. I think if the quantum computer does become available, most of the bitcoins would all be mined by then if not all. If a new cryptocurrency (other than the ones available) were to become popular, it may need to consider Quantum computing whereas bitcoin doesn't.
Why would you think a quantum computer would be able to solve SHA256 any faster then a regular computer? The problem is that a quantum computer could potentially compute the private keys of other wallets.
