  Unforgeable quantum money tokens were the first invention of quantum
information science, but remain technologically challenging as they require
quantum memories and/or long distance quantum communication. More recently,
virtual "S-money" tokens were introduced. These are generated by quantum
cryptography, do not require quantum memories or long distance quantum
communication, and yet in principle guarantee many of the security advantages
of quantum money. Here, we describe implementations of S-money schemes with
off-the-shelf quantum key distribution technology, and analyse security in the
presence of noise, losses, and experimental imperfection. Our schemes satisfy
near instant validation without cross-checking. We show that, given standard
assumptions in mistrustful quantum cryptographic implementations,
unforgeability and user privacy could be guaranteed with attainable refinements
of our off-the-shelf setup. We discuss the possibilities for unconditionally
secure (assumption-free) implementations.
