A public blockchain is a distributed ledger technology that is open to all users. Anyone can participate in the network, read and write to the ledger, and maintain and verify the network. A private blockchain is a distributed ledger that is controlled by one organization or entity. All participants in the network must be invited and authenticated, and the rules of access must be enforced by the owner. Private blockchains offer greater control and security, as there are fewer participants, and all transactions are subject to strict validation and authentication.