What is the difference between a public and private Blockchain?

Public blockchains are open and accessible to anyone, while private blockchains are restricted to selected people or entities. Public blockchains are typically decentralized, meaning no one entity controls the network. Private blockchains are often managed by a single organization or a consortium of organizations and offer more control over the network, its participants, and the data held within it. Public blockchains are usually faster, cheaper, and more secure than private blockchains because there is no single point of failure. Private blockchains may offer more control and privacy, but at the cost of scalability and security.