Cash Flow

As I ease into mooring and dock fees I keep having to expand on the givens.

Money.

Imperial currency is elaborately designed to prevent counterfeiting; but cash has many disadvantages.  Not least of which is a requirement for physical transfer of the funds.  You might notice that we don't do much of that even today at TL8...

Imperial currency, like the US dollar, is a fiat currency.  Its value is really based on a mind game:

A credit is worth something because the seller will accept it in exchange for the goods I want to buy.  Their acceptance is predicated on the belief that they too will be able to exchange it for goods they want later.

The credit transactor makes this electronic, and must be "loaded" with cash at a bank or imperial credit kiosk (think ATM machine) or with secure funds from a direct transfer.

Direct transfers occur by linking transactors through any number of communications systems.  The encryption is robust and trusted.  Trusted is the important part here.

While the computers would be amazing by our GURPS TL8 standard, they're kind of clunky compared to what the state of the art could build if unfettered by backwards compatibility and parts interchange.

The GURPS TL10 (LBB TL: C) computer is the Imperium wide standard.  The reason for this ossification of computer technology is there's a real need to be able get parts for your Type A Free Trader at any place in the Imperium from The Rim to Behind the Claw.  Some of these ships are hundreds of years old!  And people today think a B-52H is a dated design!

These "clunky" centuries old designs are far beyond anything we have today.  The distance technologically is the same as between what you're reading this on and a difference engine.  The state of Traveller art at GURPS TL12 (LBB TL: F) is as advanced again that far from the average.

The handshake for financial transactions is standardized with this in mind.  It's as secure as secure can be, and the only people who really have the hardware to readily crack it are the same people who've a vested interest in seeing it remain secure.

It turns out it's relatively simple to keep ahead of SOTA brute force decryption with an older machine, just keep adding bits to your key until the solution time falls below the level where you're comfortable.  If the people cracking your encryption have resorted to brute force, you've 80% won the match already.

Yes, there is counterfeiting.  Some.  It never gets very big and it never gets very far.  In addition to the black, The Imperium owns the currency.  Because there's a high degree of personal freedom and egalitarianism present in The Third Imperium we tend to forget that it's not a representative democratic republic.  It is a feudal monarchy.  There are several places in Imperial law where the process is very abbreviated; counterfeiting is one such place.  It has zero tolerance for counterfeiters and less sense of humor about it.  Imperial Warrants are issued with, "find them and kill them, do whatever it takes," orders.  Open ended warrants like that are taken very seriously indeed.  In addition, the real organized criminals have come to recognize that devaluing the currency with fake money is too short a con to bother with, and it only hurts their long game.