# Casper the Friendly Finality Gadget (FFG) ## Algorithm * validators stake a portion of their Ethers as stake. * validators start validating the blocks. when they discover a block which they think can be added to the chain, they will validate it by placing a bet on it. * If the block gets appended, he validators will get a reward proportionate to their bets. * Malicious validator acts trying to do a “nothing at stake”, the will immediately be punished, and all of their stake is going to get slashed. ## Pros * all Pros of Proof of stake * punish validator trying to do a “nothing at stake” attack, * punishing miners who go offline, unintentionally or not, ## Used in * Casper the Friendly Finality Gadget (FFG), hybrid PoW/PoS that will be implmented first and ease transtion to full PoS. blocks are mined using POW, every 50th block a POS checkpoint where finality is assessed by a network of validators will be used. Read [Vitalik’s note on hybrid PoW/FFG](https://vitalik.ca/files/casper_note.html), his [medium post on minimal slashing conditions](https://medium.com/@VitalikButerin/minimal-slashing-conditions-20f0b500fc6c) and the [FFG paper](https://arxiv.org/abs/1710.09437). * Casper the Friendly GHOST: Correct-by-Construction (CBC): full PoS ### Resources *