"Blockchain is a shared, distributed ledger on which transactions are digitally recorded and linked together so that they provide the entire history or provenance of an asset. A transaction is added to the blockchain only after it has been validated using a consensus protocol, which ensures it is the only version of the truth. Each record is also encrypted to provide an extra layer of security. Blockchain is said to be “immutable” because the records cannot be changed and transparent because all participants to a trade have access to the same version of the truth."
IBM. July 2nd, 2018