What does immutability mean in the context of blockchain?

In the context of blockchain, immutability refers to the principle that once data is recorded on the blockchain, it cannot be altered or deleted. This characteristic is fundamental to blockchain technology and ensures the integrity and reliability of the data stored. Each block in a blockchain contains a unique hash of the previous block, creating an immutable chain of records. Any attempt to change the information in a block would affect its hash and, consequently, render the subsequent blocks invalid, making such alterations easily detectable.

This immutability is vital for maintaining trust in a distributed system, as it prevents tampering and fraud. In applications ranging from financial transactions to supply chain management, this property enhances transparency and accountability, as all participants can verify the authenticity of the records without relying on a central authority.

In contrast, the other options discuss aspects that do not align with the core definition of immutability in blockchain technology. The ability to frequently update records or alter them for accuracy contradicts the concept of unchangeable data, while the capacity to share data across multiple blockchains pertains more to interoperability rather than immutability itself.