how is proof of stake different from proof of work 
both consensus mechanisms help blockchains synchronize data validate information and process transactions each method has proven successful at maintaining a blockchain although each has pros and cons however the two algorithms have very different approaches under pos block creators are called validators a validator checks transactions verifies activity votes on outcomes and maintains records under pow block creators are called miners miners work to solve a hashing problem to verify transactions in return for solving it they are rewarded with a coin to buy into the position of becoming a block creator you need to own enough coins or tokens to become a validator on a pos blockchain for pow miners must invest in processing equipment and incur hefty energy charges to power the machines attempting to solve the computations the equipment and energy costs under pow mechanisms are expensive limiting access to mining and strengthening the security of the blockchain pos blockchains reduce the amount of processing power needed to validate block information and transactions the mechanism also lowers network congestion and removes the rewards based incentive pow blockchains have goals of proof of stakeproof of stake is designed to reduce network congestion and address environmental sustainability concerns surrounding the proof of work pow protocol proof of work is a competitive approach to verifying transactions which naturally encourages people to look for ways to gain an advantage especially since monetary value is involved bitcoin miners earn bitcoin by verifying transactions and blocks however they pay their operating expenses such as electricity and rent with fiat currency so what s really happening is that miners exchange energy for cryptocurrency which causes pow mining to use as much energy as some small countries 4the pos mechanism seeks to solve these problems by effectively substituting staking for computational power whereby the network randomizes an individual s mining ability this means there should be a drastic reduction in energy consumption since miners can no longer rely on massive farms of single purpose hardware to gain an advantage for example ethereum s transition from pow to pos reduced the blockchain s energy consumption by 99 84 5the first cryptocurrency to adopt the pos method was peercoin several others followed soon after but ethereum was the blockchain where it made the biggest impact 6proof of stake securitylong touted as a threat to cryptocurrency fans the 51 attack is a concern when pos is used but it is doubtful it will occur under pow a 51 attack occurs when an entity controls more than 50 of the miners in a network and uses that majority to alter the blockchain in pos a group or individual would have to own 51 of the staked cryptocurrency it s very expensive to control 51 of staked cryptocurrency under ethereum s pos if a 51 attack occurred the honest validators in the network could vote to disregard the altered blockchain and burn the offender s staked eth this incentivizes validators to act in good faith to benefit the cryptocurrency and the network 1most other security features of pos are not advertised as this might create an opportunity to circumvent security measures however most pos systems have extra security features in place that add to the inherent security behind blockchains and pos mechanisms 1