Blockchain is a decentralized, distributed digital ledger that records transactions in a secure and tamper-evident way. It was first introduced in 2008 as the technology behind the cryptocurrency Bitcoin, but it has since been applied to many other industries.
At its core, blockchain is a chain of blocks, where each block contains a list of transactions. When a new transaction is made, it is verified and added to a block, which is then added to the chain. Once a block is added to the chain, it cannot be altered or deleted, which makes the ledger secure and tamper-proof.
The security of the blockchain is based on cryptographic algorithms that ensure that transactions can only be added to the ledger by authorized parties. Each block is linked to the previous block in the chain through a cryptographic hash, which ensures that any changes to the chain will be detected.
There are two main types of blockchain: public and private. Public blockchains, like Bitcoin and Ethereum, are open to anyone, while private blockchains are restricted to a specific group of users. Private blockchains are often used by businesses to create their own internal ledgers to manage transactions between different departments or partners.
Blockchain has many potential applications beyond cryptocurrency. For example, it can be used for supply chain management, where it can track the movement of goods from the manufacturer to the end consumer, or for identity verification, where it can provide a secure way to store and share personal information. It can also be used for voting systems, smart contracts, and many other applications.