my first question here, so please be patient with me. Thank you in advance.
Q: Why exactly are POW/POS mechanisms needed to secure the blockchain (in bitcoin as well as in other alts)? + what is terribly wrong with my example below and why ? (I feel like I am missing something very important here). Thank you very much.
I mean: - why the block verifying and signing party cannot be just randomly selected node, that would every X minutes put new transactions into the block, calculate hash of block and sign it by its public key, broadcast it to other nodes for inclusion in the blockchain and collect some the reward ? (provided nodes on the network are able to reach some kind of consensus on selected random node - I know it is not easy task - but let's assume it can be done for a moment)
I mean, possible attacks on the network are still there, but it is same as with POW/POS, but:
- if node is selected 'truly randomly' (I know, I know), the attacker would need to have just pure luck if he wants to fork the chain with his crafted transactions, because he does not know when he will have the privilege to sign the block...
- Or he would need to increase its share of nodes in the network significantly (same with 51% attack in POW/POS)
Above can be (?) mitigated to some degree with including check points in every N blocks in the best chain and having the rule of including e.g. hash of N-x block into recent transactions. (at least from what I understand, that is what some POS coins do)
Why there needs to be POW/POS? (electricity burning/(locked) coins in wallet staking)
Thank you very much for putting my thought process back on track.