https://en.bitcoin.it/wiki/Altcoin#Proof_Of_Stake https://en.bitcoin.it/wiki/Altcoin#Proof_Of_Stake Because these attacks exists, including Peercoin[3] and B

https://en.bitcoin.it/wiki/Altcoin#Proof_Of_Stake https://en.bitcoin.it/wiki/Altcoin#Proof_Of_Stake Because these attacks exists, including Peercoin[3] and Blackcoin[4] proof of stake cryptocurrencies have "master" public keys that control the blockchain. I wonder who would control that ;) This class of cryptocurrency is either insecure or centralized, however proof of stake (based on a PoW currency) is useful in some systems because gaining stake is costly, but it isn't workable for bootstrapping distributed consensus. This would be an interesting though experiment. If they implemented proof of stake based on a proof of work currency, like Bitcoin, what would happen if the new currency took off and Bitcoin started to die? Now there's a threat model that requires unmotivated miners to still secure the network, both networks.