PoPP = Proof of Payments Processed
You can find all here: https://support.metalpay.com/hc/en-us/articles/115000369474-What-is-PoPP-
PoS = Proof of Stake
Proof of Stake is a proposed alternative to Proof of Work. Like proof of work, proof of stake attempts to provide consensus and doublespend prevention. Because creating forks is costless when you aren't burning an external resource Proof of Stake alone is considered to an unworkable consensus mechanism
Benefits of PoS:
- No need to consume large quantities of electricity
- Not as much need to issue as many new coins
- Discourage centralized cartels (like Selfish Mining in PoW)
- Reduced centralization risks
PoW = Proof of Work
With Bitcoin, which has made the blockchain technology popular, the so-called "proof of work" algorithm (PoW) was developed. In principle, each participant in the Bitcoin network can participate in the block generation. In order to confirm the transaction and enter a block into a blockchain, a miner has to provide an answer, or a proof, to a specific challenge.
Miners use PoW to validate transactions and mining new coins, but its main goal is to block potential cyber-attacks or suspicious activities within the network. Each times a miner confirm a transaction, he is reward with coins. The only disadvantage in this technique is it’s a costly and intensive process.