user41513: What are similarities and differences between Tendermint consensus and Proof-of-Stak?
For example, in both consensus, a validator is selected randomly (I think in Tendermint consensus they are selected in a round robin process). 
And I think in Tendermint consensus, validators are known and pre-selected, unlike Proof-of-Stake consensus. Is it true? and if yes, what entity does confirm a known validator?

user88750: Yes they are known. They are selected via a round-robin fashion. The Tendermint team intend to add a VRF to randomly select validators:
https://github.com/tendermint/tendermint/issues/763

41513: <p>What are similarities and differences between <strong>Tendermint</strong> consensus and <strong>Proof-of-Stak</strong>?</p>

<p>For example, in both consensus, a validator is selected randomly (I think in Tendermint consensus they are selected in a round robin process). </p>

<p>And I think in Tendermint consensus, validators are <strong>known</strong> and <strong>pre-selected</strong>, unlike Proof-of-Stake consensus. Is it true? and if yes, <strong>what entity</strong> does confirm a known validator?</p>
 88750: <p>Yes they are known. They are selected via a round-robin fashion. The Tendermint team intend to add a VRF to randomly select validators:</p>

<p><a href="https://github.com/tendermint/tendermint/issues/763" rel="nofollow noreferrer">https://github.com/tendermint/tendermint/issues/763</a></p>
