# Understanding Serenity, Part 2: Casper

DevFeed: [Understanding Serenity, Part 2: Casper](<https://devfeed.tech/articles/understanding-serenity-part-2-casper-16740.md>)

Original publisher: [Read original article](<https://blog.ethereum.org/en/2015/12/28/understanding-serenity-part-2-casper>)

Author: Vitalik Buterin

Published: 2015-12-28T01:54:30Z

Content type: article

Language: en

Sources: [Ethereum Foundation Blog](<https://devfeed.tech/sources/ethereum-foundation-blog.md>)

Topics: [Ethereum](<https://devfeed.tech/topics/ethereum.md>), [Algorithm](<https://devfeed.tech/topics/algorithm.md>), [Protocol (disambiguation)](<https://devfeed.tech/topics/protocol.md>)

Tags: [algorithm](<https://devfeed.tech/tags/algorithm.md>), [consensus](<https://devfeed.tech/tags/consensus.md>), [ethereum](<https://devfeed.tech/tags/ethereum.md>), [proof-of-work](<https://devfeed.tech/tags/proof-of-work.md>), [protocol](<https://devfeed.tech/tags/protocol.md>), [research-development](<https://devfeed.tech/tags/research-development.md>)

## AI overview

This article explains Casper, Ethereum's proof-of-stake algorithm for the Serenity milestone. It presents consensus-by-bet, in which validators receive rewards or penalties based on which blocks they support, and describes how incentives are intended to drive convergence toward a shared state.

## Source excerpt

Special thanks to Vlad Zamfir for introducing the idea of by-block consensus and convincing me of its merits, alongside many of the other core ideas of Casper, and to Vlad Zamfir and Greg Meredith for their continued work on the protocol In the last post in this series, we...