This should be in all stickys and faq's! Seems like every week lately we have a thread on this same old topic. I know the search engine is very bad on this forum, but i think most of the noisemakers are just too lazy to even use it.
I think at least
this video from the summit should be compulsory to watch before being able to post on this forum.
...except that the speaker got the question about quantum computing wrong. I was in the audience, but I was too much of a pussy to stand up and correct him in front of everyone. Apparently, I should have done so (since he has now been cited by someone), but I'm shy like that -- especially because I was in the back and no one had any idea who I was. Oh well.
The speaker says that ECDSA is not susceptible to QCs -- that's just wrong. ECDSA is most definitely broken by QC's, as well as just
most asymmetric crypto algorithms on which internet security relies. But Bitcoin is better prepared to deal with QCs than most other crypto systems: (1) if you never reuse addresses, then no one knows your public keys and thus there's nothing for a QC to solve. By the time someone gets your public keys, you've already spent the funds, (2) the crypto algorithms in Bitcoin can be changed to quantum-resistant ones. Given that we'll probably have two decades advance notice before QCs with enough qubits exist to even threaten Bitcoin, we'll have plenty of time to make the switch.