Blockchain technology is a digital innovation that is poised to significantly alter financial markets within the next few years, within a cryptographic ecosystem that has the potential to also significantly impact trusted computing activities and therefore cyber security concerns as a whole. 

At its core, blockchain is a distributed data store. As opposed to traditional data repositories, which store data in centralized servers and server clusters, blockchain creates copies of its ledger and stores it on thousands and millions of computers, also called nodes. A reasonable number of nodes must validate every new record before it is registered. Once confirmed, the record is stored in the ledger and propagated across the network of participating nodes.

• An append-only sequential data structure
• New blocks can only be appended at the end of the chain
• To change a block in the middle of the chain, all subsequent blocks need to be changed
• Very inefficient compared to a relational database