All cryptocurrencies are based on some type of protocol which is consisted out of rules and regulations for validating transactions. Most of them use POW protocol which relies on miners and their good will, expertise and a lot of spent electricity, to ‘solve blocks’ or validate transaction of funds. They get some coins in return, for their effort. Right now, things are changing for some cryptocurrencies, like Ethereum. They are switching from Proof-of-work protocol to a so-called Proof-of-stake protocol (PoS). New, PoS protocol for Ethereum is called Casper and will bring a lot of new assets to the table.