What is POW and POS ?
Ans. The first timestamping scheme invented was the proof-of-work scheme. The most widely used proof-of-work schemes are based on SHA-256 and scrypt. The latter now dominates over the world of cryptocurrencies, with at least 480 confirmed implementations.
Some other hashing algorithms that are used for proof-of-work include CryptoNight, Blake, SHA-3, and X11.
What is Proof-of-stake (POS) ?
Ans. Some cryptocurrencies use a combined proof-of-work/proof-of-stake scheme. The proof-of-stake is a method of securing a cryptocurrency network and achieving distributed consensus through requesting users to show ownership of a certain amount of currency. It is different from proof-of-work systems that run difficult hashing algorithms to validate electronic transactions. The scheme is largely dependent on the coin, and there's currently no standard form of it.