Sort:  

I do think that quantum computing is not yet available to most of us, but the mere fact that it is possible to crack the cryptography that most blockchains currently use is very worrying. It is very possible that someone with access to it will suddenly abuse it. I think this is a big challenge for crypto devs to tighten up security for the future.

Better them than me! I have little doubt the day is coming when some fundamental changes have to happen.