value that stays stable over time.

Both the Bank of England[^7] and the central bank of Canada[^8], using Bitcoin as a case study, found that crypto-currencies do not currently fulfill these functions in the way that fiat currencies and e-money do. However, it is of course possible that in the future, a more widespread uptake in a particular crypto-currency may lead it to it satisfying this criteria. This is not necessarily the view held in all jurisdictions throughout the world, we will discuss recent changes proposed to this view in for instance Australia, in Section \[sec:regulation\].

Separate from the *functions* of money, one can also explore particular *qualities* of money that make it suitable for facilitating transactions. In the case of commodity money, these include durability, value per weight unit (portability), and scarcity, and [@graf2015commodity] argues that Bitcoin evaluates well on each characteristic. As these currencies were primarily oriented towards direct, online transactions, we can additionally consider the following qualities in the context, e.g. of online commerce [@drehmann2002challenges]:

-   They should be low cost;

-   they should provide reliable security; and

-   they should offer a degree of privacy in transactions.

See further discussions on these points in [@maurer2013perhaps].

Two 