It's pretty convincing so far though that P != NP, all NP problems can be reduced to the four color map problem, and that means that if any one NP problem can be shown to be P, then all NP problems can be solved in polynomial time. I believe there are huge bounties and lots of researchers attempting to do this with any number of NP problems.

Of course, it could be that someone does it one day, and if so modern cryptography is useless, but I highly doubt it.