Public blockchains, such as Bitcoin and Ethereum, are open to anyone and provide transparency and decentralization. They are secured by a distributed network of nodes and are often used for cryptocurrencies and decentralized applications. Private blockchains, on the other hand, are restricted to specific organizations or groups, offering more control and privacy. They are used in enterprise solutions where access needs to be limited and data confidentiality is crucial. Private blockchains often have faster transaction speeds and lower costs compared to public ones.
source:
https://www.blockchainappfactory.com/blockchain-development-company