Proof-of-stake (PoS) is a type of consensus algorithm of a cryptocurrency’s blockchain network. In a PoS cryptocurrency, block creators are chosen by random selection with the consideration of the user’s wealth in the network and, sometimes, the age of his assets that is often referred to as the “coin age.” Unlike proof-of-work (PoW), miners of PoS cryptocurrencies must have some coins to continue mining. PoS blockchains are much more energy efficient than PoW blockchains and are more engaging in the accumulation of wealth. Bitcoin enthusiasts sometimes offer PoS as an alternative to PoW that might be implemented in Bitcoin’s blockchain. PoS for Bitcoin may be implemented as a hybrid of PoW and PoS to engage people with less powerful computers in the network. Famous examples of PoS cryptocurrencies are DASH, NEO and Stratis.