Long story short: POSA is a consensus mechanism, which KCC uses to verify transactions. However if you get into the finer details, it’s not that easily explained.
Be aware that even this explanation takes a rather shallow approach into explaining everything and might simplify details here and there.
What is a Consenus?
Consensus is the way a blockchain verifies transactions. BTC and ETH use POW(Proof of Work) right now, but ETH plans to switch over to POS (Proof of Stake) in the future, although it has been delayed quite a bit so far.
Proof of Work seems like a decentralized approach, but partly thanks to mining pools the dezentralization isn’t as prelevant as it could be.
Also POW takes a lot of electrical energy, as the higher the price of the underlying coin rises (and with that how high rewards for mining get) the more people want to get in and mine. This raises network difficulty to compensate for the influx of miners.
Just for verifying transaction both BTC and ETH wouldn’t require anywhere near as much electricity. What causes this is the profitability of mining.
Now what is POS?
POS is a different mechanism, where nodes with a certain amount of stake can verify transaction. This is more energy efficient as the consensus relies more on the nodes having a backing in the base currency, than doing hard calculations. POS nodes are rewarded with the base currency just like miners are in POW.
But what is PoSA then?
PoSA is a mix of POS and yet another consensus mechanism called POA.
With PoSA not everyone can simply start a node, the node owner has to submit a proposal to the network first and once over half of the active validators have voted on it, the node itself can also become a validator.
Only the top x amount of validators are able to mine blocks. The order is given by the stake amount to each validator.
This is a more centralized approach than POS but allows for faster block times and with that faster transactions.
PoSA on KCC
On KCC up to 29 active validators are supported. The goal is to have low transaction costs, low transaction delay and high transaction concurrency.
KCC is also an EVM chain, which makes it so that any Dapp build on Ethereum networks can be ported over easily and so that many of the existing tools can also be used for KCC. This allows for developers to use known tools and existing code bases.
