Bitcoin is a decentralized digital currency that is based on a proof-of-work system. This system requires miners to solve complex mathematical puzzles in order to confirm Bitcoin transactions. The miners are rewarded with Bitcoin for their work, creating a self-sustaining system.

The puzzles are designed to be difficult, so that only the most powerful computers can solve them. This ensures that Bitcoin remains secure and reliable. It also allows the system to remain decentralized, as miners from all over the world can participate in the process.

This proof-of-work system has been instrumental in making Bitcoin the success it is today. It is one of the main reasons why the currency is used by so many people around the world. As the system continues to evolve, it will become even more secure and reliable.