Public and private blockchains

A public blockchain is open to anyone. Anyone can read it, send transactions and, on most networks, help run it. Bitcoin, Ethereum, Solana, XRP Ledger and Algorand are all public. No single company is in charge, which makes them hard to shut down or censor, but it also means there’s no one to call when something goes wrong.

A private blockchain, also called a permissioned blockchain, only lets approved members join. A company or a group of firms decides who can read the records and who can add blocks, often using proof of authority. That gives more control over privacy and over who you’re dealing with, which is why many banks test or run tokenization projects this way.

The choice is a trade-off. Public blockchains reach more people and don’t depend on one operator, but you can’t choose who else is on them, and anyone can see the transactions. Private blockchains give you more control, but fewer people can use them, and you have to trust whoever runs them. Some projects try to connect the two. Which kind is right, and which risks matter, depends on what you need the blockchain for.