Blockchains are a chain of blocks that contains information. It was first introduced back in 1991 by two researchers and was first intended to notarize digital documents so it would not be possible to tamper them or change them, and they called it "Digital Timestamps." It was not adopted by many, but in 2008 a coder named "Satoshi Nakamoto" used this idea and technology for his project, "Bitcoin." Bitcoin is a cryptocurrency, "crypto" from the word cryptography means "is the study of secure communications techniques that allow only the sender and intended recipient of a message to view its contents." and currency "is a medium of exchange for goods and services. In short, it's money." Bitcoin also acts as a distributed public ledger, which means all of the transactions are recorded on the blocks, and anyone can see those data, but not anyone can change even one single character.