If "P=NP" then the blockchain and the cryptoworld will collapse (the same with credit cards, emails, and internet in general). Because it implies that there will be a way to find (crack) a private key in a reasonable period of time. Then the wallets of all people will be compromised.
The solution would be using very very large passwords with the obligation to change them every week or month.
So, cross your fingers for someone to proof that P is not NP.
think again though :)
Give me a hint ☺