What Are the Main Differences in Security between Proof of Work and Proof of Stake?

The main security difference between Proof of Work (PoW) and Proof of Stake (PoS) lies in how they deter attacks. PoW relies on computational power, making attacks expensive due to hardware and energy costs.

PoS relies on validators staking their own cryptocurrency, so an attack would require owning a majority of the currency, which is also economically prohibitive. PoW is generally considered more battle-tested and secure due to its longer history.

In PoS, a 51% attack is still theoretically possible if an entity acquires a majority of the staked coins.