The difference between POW / POS / POA / POA

I’ve been using/involved with crypto for a couple of years now, I think like most people I started off trying to maybe make a bit of money.

But over the past few months I’ve become more and more interested in learning about it more in-depth, learning more about blockchain technology, trying to get more involved with DeFi, DEX and Dapps.

It seems the more you learn the more you realise there is to learn still.

I’ve been trying to learn a bit more about “Proof of’s” , We’ve all heard proof of work and proof of stake but what they actually meant I had no idea, I also didn’t know there was more “proof of’s” than POW & POS.

I thought I’d try and explain what they are, maybe teaching someone new but also someone who knows more than me can correct me.

PROOF OF WORK

Proof of work starts with a block, The Genesis Block or Block zero from there miners have computers running algorithms which solve complex equations in an almost race to get the equation completed first, Once the computer has worked out the correct answer to the equation they broadcast it to the network and that is verified by other miners, once it is verified the block is added to the blockchain, which means they get to submit the next block and get a reward of 6.25BTC. This figure halves at certain intervals, think when you hear bitcoin halvening, this is it, so it used to be 12.5BTC as a reward. The next block always refers to the block before to keep the ledger updated and past transactions noted.

Nodes, Also computers running software will verify transactions one the blockchain (think when you send a cryptocurrency it has to be verified x amount of time before it arrives in the destination wallet) having these nodes stops double spending.

List of POW cryptos - BTC, ETH, LTC, DOGE, XMR and many more.

PROOF OF STAKE

Proof of Stake also starts with a genesis block which other blocks refer to and are added to but miners don’t compete using more and more computing power solving equations but instead stake the native token in a contract with the blockchain. If you have 3 miners that stake 10,20 and 30 coins respectively, miner 3 will get to write the block and mint it to the blockchain they will receive network fees for this.

EDIT - u/xxexoxx665 Correctly pointed out

And if I'm not mistaken in pos the amount of tokens you hold are equivalent to the chance of you getting to mint the next block. The way your phrased it sounds like the biggest whale always gets to do it.

My wording wasn't great.

Users can also pool their coins/tokens together to collectively be given rights to write the block and receive a portion of the rewards respective of their staking percentage.

List of POS cryptos - ADA, SOL, ALGO, XTZ, CELO and again many more.

PROOF OF AUTHORITY

Proof of authority is similar to POS in the sense instead of staking coins/tokens you stake you reputation. Validators are chosen and have to meet certain requirements. They have to verify their real identities, it is difficult to become a validator and they have to be willing to invest money and put their reputation at stake. Having a tough process weeds out unworthy candidates. Once you are chosen and your node is selected is a trustworthy reputation your node then verifies transactions onto the blockchain.

A downside of POA is the lack of decentralisation as a company/project selects the validators.

List of POA cryptos - VET, VEN and CRO I couldn’t find any further examples.

PROOF OF ACTIVITY

Proof of activity combines POW & POS.

It starts out like POW and once a new block has been mined it switches over to POW.

The mining process starts with validators racing to mine a new block but once that block is mined it switches over to POS where a group of validators are selected to validate the block similar to POS the more coins/tokens a validator has the more chance they have of being selected. The rewards are split between the miner and the validators.

List of POA examples - The only one I could find was Decred (DCR)

If anyone can correct me on anything I more than welcome it as it helps me learn and if anyone learnt anything then that’s cool too. Hopefully this is helpful and interesting to someone.

EDIT - As u/Xohduh pointed out SOL runs on POS and POH( Proof of History ), I've never heard of POH and never came across it whilst looking and learning.

I'm still trying to understand how it works but I've found this site and video to help.

https://youtu.be/7UE5UFd-b2c

https://medium.com/solana-labs/how-solanas-proof-of-history-is-a-huge-advancement-for-block-time-178899c89723