Blockchain is a decentralized, digital ledger technology that enables secure, transparent and tamper-proof transactions. It uses a chain of blocks that hold batches of valid transactions, and every block contains a cryptographic hash of the previous block, a timestamp, and transaction data. This allows for the creation of a permanent and unchangeable record of transactions across a distributed network of computers, without the need for a central authority. Blockchains use consensus mechanisms, such as proof-of-work or proof-of-stake, to ensure integrity and security of the network. This technology is mainly used for cryptocurrency but it has various other potential use cases such as supply chain management, voting systems, digital identity and many more. There are different types of blockchain like public, private and consortium blockchain, with their own unique characteristics and use cases.