If we suppose that it is found that P=NP, how will security measures need to be changed?
I'd like to know the major security measures that are affected, and how they would need to be changed. We can suppose that passwords can be hacked in time O(n^4), for the sake of argument.
As an example of what I'm partly looking for, we might have an answer like RSA passwords of 1,024 bits would need to be extended to 5 million bits, or SSH would be rendered insecure. I guess I'm attempting to get a scientific measure of changes that should take place without getting into the realm of speculation. So we would probably have to first determine what level of security is adequate, and then compare the necessary changes. So to have this level as part of the question, we can simply use common security practices in effect today.
I'm somewhat of a novice in the realm of IT security, so I'm hoping that someone can help point out what's important to know in this scenario.