What is a primary feature of private blockchains?

A primary feature of private blockchains is permission-based access controls. This means that access to the blockchain network is restricted and controlled by a central entity or a predefined group of participants. In a private blockchain, only authorized users can join the network, thereby ensuring that sensitive data and transactions are shared only among trusted parties. This contrasts with public blockchains, where anyone can participate and access the blockchain's data.

This feature is particularly important for organizations that need to maintain privacy and confidentiality while still leveraging the benefits of blockchain technology. The ability to control who can read and write to the blockchain helps in managing compliance and governance aspects, ensuring that only those with the appropriate permissions can interact with the network.

In private blockchains, the lack of open access to all users, the absence of a built-in cryptocurrency (which is more common in public blockchains), and although transactions can be immutable, this is not unique to private blockchains as immutability is a characteristic found in all blockchain types. Thus, permission-based access is a defining feature that sets private blockchains apart.