Well, it needs secure currency. I agree that physical Imperial Credits are important, but numbers run to high for those to be the only option.
For serious funds transfers, I'd think in terms of a secure chunk of electronics that's physically loaded with value at one location and delivered to another one to be securely unloaded. Possibly requiring physical return to the original location to finalise the transaction, and a final confirmation sent to authorise release of funds.
Think the US checking system.
Although if you can make uncounterfeitable credit notes, you should be able to make a secure electronic wallet.