Say there is someone claiming to have solved P vs NP, by finding a (computationally feasible, i.e. no huge constants) polynomial solution to a problem in NP:
Apart from a formal proof, is there any kind of challenge comparable to the RSA Numbers, which could be used to "prove" (or at least give strong evidence) that you have indeed found a polynomial solution to a NP problem?
[For comparison: If I claim to have found a solution to FACTORING and present factors for RSA-2048, that might not actually prove my approach, but would make my attempt a lot more credible]