Bitcoin was launched by Satoshi Nakamoto, a pseudonym for the mysterious and elusive publisher(s) of an article describing how cryptography, combined with a distributed public ledger, could be used to implement a digital currency without a central authority to authenticate payments. Traditionally, people can exchange money with those they do not know because both actors trust a third party, usually the validity of a banknote or an intermediary such as a bank or currency exchange. Nakamoto's system has no hard currency and no intermediary, but creates a trustworthy system through innovative use of cryptography and peer-to-peer networking. When one user sends Bitcoin to another, the transaction's details (such as sender and receiver addresses and the amount of funds transferred) are broadcasted to the Bitcoin network, so that the transaction can be validated by all network peers. Once it has been validated by the network, the transaction is packaged into a 'block' of transactions, and added, through the 'mining' process, to the ever-growing list of blocks that form the blockchain ledger. This list is stored by peers in the network. Bitcoin also has a feature whereby new bitcoins are generated and added to the system, having an inflationary effect. These are distributed to miners (in addition to the sum of transaction fees in the block) as a reward for successfully adding transactions to the blockchain. Mining can be done by any user with any computer, but an industry of professional miners has emerged, using dedicated computers developed especially for the purpose. The distributed structure of the system coupled with its cryptographic functionality make Bitcoin incredibly robust. The trust required to enable transactions is achieved through the knowledge that all transactions – past, present and future – are witnessed (albeit automatically) by all users. \cite{Drescher_2017}