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What is the Proof of Stake and how this concept is (or will be) related with Ethereum?

marked as duplicate by Badr Bellaj, MidnightLightning, AdrianClv, Matthew Schmidt, eth Jun 3 '17 at 0:04

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From Wikipedia:

Proof-of-stake (PoS) is a method by which a cryptocurrency blockchain network aims to achieve distributed consensus. While the proof-of-work (PoW) method asks users to repeatedly run hashing algorithms or other client puzzles, to validate electronic transactions, proof-of-stake asks users to prove ownership of a certain amount of currency (their "stake" in the currency). Peercoin was the first cryptocurrency to launch using proof-of-Stake. Other prominent implementations are found in BitShares, Nxt, BlackCoin, NuShares/NuBits and Qora. Ethereum has planned a hard fork transition from PoW to PoS consensus. Decred hybridizes PoW with PoS and combines elements of both in an attempt to garner the benefits of the two systems and create a more robust notion of consensus.

Vitalik Buterin explains here and here how Ethereum will be related to Proof of Stake.

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    anyone interested in the topic might listen to soundcloud.com/epicenterbitcoin/eb-105 it's absolutely not technical and explains very well how Casper deals with the Long-Range Attack and Nothing-at-Stake issue POS brings. – euri10 Mar 29 '16 at 13:25

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