[cortesoft]

There is one important property of currency that you are missing in your list: accepted. Currency that is not accepted as payment for things has little use as currency. It is easy enough to create something that meets all of your requirements, but unless people are willing to accept the currency in exchange for goods and services, it is useless.

Of course, currency has a very strong network effect. Its value is tied very closely to the number of people who use it.