Barcode Cash

The recent discussion about high denomination banknotes has extended into the merit of paper cash.

In so far as paper cash is needed, does it need to be done the old school way? For buying goods in legal market, probably not, an alternative would be to use “bearer numbers” (implemented as QR-code or barcode) that could be printed on paper if people want that.

The way it would work would be something like:

• ATMs are replaced by an online banking facility that debits the client’s account, credits the bank’s account at the central bank (or whoever is the barcode cash clearer), which in response issues a new random number associated with the amount. The number is printed in computer readable form on a ticker the punter puts in their wallet.
• In a shop the punter shows the number (the ticket) which the cash register redeems with the central bank computer. A new number is issued for change and printed on the receipt. These numbers can then be spent at other shops.
• People can also simply give away the printout to others, as long as the recipient trusts the giver not to spend a copy before them.
• Splitting a ticket would require an online app similar to the shop’s cash register.

This reproduces something similar to paper cash but without the need for actual ATMs with a stock of high value banknotes, or a banknote printing and processing infrastructure.

The principal disadvantage is that it requires all non-trusted-parties transactions to be online, to check the value and validity of the number with the centralised issuer/redeemer computer system.

The issuer could be a Bitcoin-like system — you can indeed do all of the above with Bitcoin — though current blockchain technologies add a delay to transaction authorisation that’s impractical for most shop-style settings.

It could be argued this is less anonymous than paper-cash because all redeeming transactions are logged (like in Bitcoin).  Technically that could be done with current cash as well: banknotes have serial numbers that could be tracked to produce interesting meta-data — a government could easily mandate the use of some scanner widget in the cash registers of all legal businesses.