Most proof-of-stake networks choose validators with verifiable randomness, giving larger eligible stakes a larger selection chance.
A validator set is the trust boundary behind a Universal Bridge security model. In a Universal Bridge design, selection is only the first question; the next is how those validators agree.
What the protocol needs
It needs an active validator set, effective stake per member, and a shared random seed. Stake is weight in a deterministic function every node can recompute. On Ethereum, RANDAO supplies the seed; it assigns one proposer and committees for each slot.
Eligibility: a deposit or bond enters the active set; activation and exit rules limit churn.
