An alternative to proof-of-work , in which one’s existing stake in a currency or the amount of currency held, is used to calculate the amount of currency one can mine. Rewards for this type of mining are based upon the amounts one has already invested in the particular cryptocurrency in question. Proof-of-stake mining is generally not a stand alone mining method but is used by some cryptocurrency issuers in combination with proof-of-work mining. Peercoin and Novacoin are two major cryptocurrencies that use this combination of mining method.
Malone, J.A (2015). Glossary of Bitcoin Terms and Definitions. United States: Lulu Press, Inc
An alternative method of mining blocks that require miners to demonstrate their possession of a certain amount of the currency of the network in question. This works on the principle that miners will be disincentivized to try to undermine a network in which they have a stake. PoS is less wasteful than PoW, but is still often used together with it to provide added security to the network.