Optiv Cybersecurity Dictionary

What is Blockchain?

Blockchain is a growing list of records, called blocks, linked using cryptography. It's a decentralized, distributed and public digital ledger that's used to record transactions across many computers in a way that the record can’t be altered retroactively without additionally changing all successive blocks and the consent of the network.


Blockchain is a method to record transactions that provides high security by design: transactions are verified with advanced cryptography and spread across many computers in a peer-to-peer network (distributed ledger).


Blockchain was initially developed to serve as the distributed ledger system for the cryptocurrency, Bitcoin. Today, the applications for blockchain are expanding beyond those for cryptocurrency. By design, it's resistant to data modification. However, it does have limits.

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