What makes blockchains immutable?
Blockchain is a distributed database, stored on a large number of computers in the form of a set of identical copies. These copies are constantly synchronized, so that any new records in the database are instantaneously distributed throughout the network. New changes are recorded in a single chain of information blocks.
The blockchain system is cryptographically protected — it means that the user can make new changes to the blockchain only based on his own previous actions. “Third party” editing would be impossible for him because of the lack of a cryptographic key associated with another user and known only to the latter.
Therefore, no blockchain record can be rased or changed, because it would response immediately on all nodes of the network, what is practically impossible. So, once been recorded in the blockchain, data can not be falsified or arbitrarily deleted!
