Bitcoin utilizes a consensus mechanism known as Proof of Work (PoW). In this system, miners compete to solve complex mathematical puzzles. The first miner to solve the puzzle adds a new block to the blockchain and is rewarded with a newly minted Bitcoin.  

PoW ensures security and decentralization by requiring significant computational power. This makes it difficult for malicious actors to manipulate the network. However, it also consumes substantial energy.  

Proof of Stake (PoS), on the other hand, selects validators based on the amount of cryptocurrency they hold. Validators stake their coins, and those with larger stakes have a higher chance of being chosen to validate blocks. PoS is generally more energy-efficient than PoW, but it can raise concerns about centralization and security, as wealthier individuals or entities could potentially gain significant influence over the network.  

Bitcoin uses Proof of Work (PoW) as its primary consensus mechanism. PoW requires miners to solve complex cryptographic puzzles to validate transactions and add new blocks to the blockchain. This process is energy-intensive but ensures high security and decentralization, as attackers would need immense computational power to manipulate the network.

In contrast, Proof of Stake (PoS) selects validators based on the amount of cryptocurrency they hold and are willing to stake as collateral. PoS is more energy-efficient since it doesn’t require extensive computational work. However, it can raise centralization concerns, as wealthier participants have more influence.

While PoW emphasizes security and trust through computational effort, PoS prioritizes efficiency and scalability, making them suited to different blockchain needs.