What is a Blockchain?
A blockchain is a decentralized public ledger that helps facilitate secure digital transactions. It acts as a public database that anyone with the right software can access and read. Data can only be added by the data owners that are verified using cryptographic keys. The data is then added to a block and broadcasted out to be confirmed typically by miners or nodes. Once the block is confirmed it is then part of the blockchain which cannot be altered since it is now public record and copies are held by a global network of computers. Since there is no “official” copy it is extremely hard to change the public ledger the data’s quality is maintained by this database replication and computational trust.
This technology has many great use cases but the most popular is as a use of currency. It is used in cryptocurrencies like Bitcoin, Litecoin, Dash and many other. The reason that it works so well as a currency is that a consensus is required from the members of the global network and once a block has been confirmed and validated it will be permanently recorded. No one, not even a system administrator, can delete any part since it is replicated through the network.