What two key features define blockchain ledgers?

Blockchain ledgers are characterized by their shared and immutable nature. Being shared means that the ledger is distributed across multiple nodes or participants in the network, allowing for transparency and collective verification of transactions. This decentralization helps prevent fraud and ensures that all participants have access to the same information, fostering trust among users.

Immutability refers to the property that once data has been recorded on a blockchain, it cannot be altered or deleted without the consensus of the network participants. This ensures the integrity of the data, as any attempt to change it would be evident and could be easily rejected by the network. Thus, the combination of being shared and immutable creates a secure and reliable method for recording transactions and other data, which is a fundamental aspect of blockchain technology.