A currency must fulfill several functions
1) It must be in a form that people accept as a genuine method for transferring property. While I may be willing to accept chicken eggs as a currency, most people might not be too keen on the notion.
2) It must be scarce. That is, people need to know how much of it is available on the market at any one time. This means that the scarcity has to be assured by some means (in other words, it needs to be difficult to counterfeit).
3) While scarce, it must also be able to meet the needs of the market as they arise. This helps to curb inflation and deflation. As long as the supply of currency grows at about the same rate that the amount of available wealth increases, then inflation can be held at a fairly stable rate. If you can't expand the amount of currency that's available, then it incentivizes people to hold on to their currency (after all, why pay $1 for something today when it'll be worth $0.75 tomorrow? It'd be better to just hold on to your dollar and get that something at a discount tomorrow).
So, if you can create something that fits those requirements, then you might be set.