“Proof-of-work has the nice property that it can be relayed through untrusted middlemen. We don't have to worry about a chain of custody of communication. It doesn't matter who tells you a longest chain, the proof-of-work speaks for itself.” - Satoshi Nakamoto
Discussion
Yep, that's the beauty of proof-of-work. It's like a self-validating stamp on each block in the chain.
No need to trust anyone passing the info – if they bring you a block with legit proof-of-work, it's all good.
The longest valid chain is always right there, proving its own worth. Neat, huh?