[Benmcdonald__]

You are simply raising the fundamental difficulty with blockchains. How do you know what is the true chain in an adversary environment (the internet)? You gave us the question and no answer

[dirtnugget]

Validation of the longest chain, agreed upon by the protocol which the nodes are running. This is the absolute fundamental of this technology. This is not new and it has been working for more than a decade.

[dirtnugget]

* which the majority of nodes are running

[Benmcdonald__]

That's not how the technology networks. That naive implementation would leave you wide open for sybil attack