Thanks to everyone that +1'd my logo.
Here's a bit of an improvement, including what I think would be a good slogan.

my thumb up! Great!!!
Lose the digital cash, just make it digital
The cash bit comes from the name.
private instant digital
or
private instant cash
private instant digital, this works
private instant cash, this less so, as cash refers to money in the physical form of currency, such as banknotes and coins.
http://en.wikipedia.org/wiki/CashEdit: though I see now from the link, that cash can mean more than just that, especially in bookkeeping and finance contexts.