December 15, 2005
Due to a number of high profile money transport robberies in recent years, the Swedish national bank (Riksbanken) is considering adding RFID tags to their banknotes, reports digi.no, quoting nyteknik.se
Several types of tags are under consideration: a passive id-tag for tracking stolen banknotes would form a first step; later they are considering tags that are de-activated during transport and storage and only activated once the banknotes are paid out from a cashpoint.
Posted by andersja
How can passive RFID in individual banknotes be of any use in tracking bundles of stolen banknotes ?
There may be a case for using active RFID or other electronic tagging device on security van armoured boxes, or on pre-packed Automatic Teller Machine cassettes, but "ye cannae change the laws of physics".
It may well be possible to embed Hitachi mu chip type devices in a banknote, although there will be wear and tear problems which will reduce the life of such notes compared with ordinary ones. There will be stress concentrations where the hard , brittle, sharp RFID chip is bonded to the flexible paper or plastic banknote - a good percentage of them will simply drop out of the substrate through normal wear and tear.
Such chips could be used for the individual examination of a suspected forged or stolen note, but whether this is "better" than current printed serial number, ultraviolet inks, and anti-colour photcopier printing techniques , is debatable.
What you certainly will not be able to do is to detect and identify the individual chips within a bunch or stack of banknotes, simply because all the antennas in such close proximity (possibly two or three per millimetre), will interfere with each other, even when perfectly flat in a neat bundle. The problem becomes even worse with flexible antennas, e.g. those printed using conductive ink are ok for labels which are stuck onto more solid packaging, but are useless when bent or folded like banknotes will be. Consequently many of the chips will not even power up properly.
Remember that the distance between adjacent banknote embedded RFID chips will be far less than the wavelength of the licence free Industrial Scientific Medical radio waves which most RFID chips are designed to use.
Even millimetre wave frequencies i.e. 30 to 100 Gighertz will be hard pushed to work with a wad of banknotes, even at very short range. The huge privacy risk of using such millimetre waves at longer ranges, is that they can be used as "see through your clothes" scanners, so anything capable of checking the money in your wallet, can also "see" you or or children "naked". Hopefully there might be some public outcry over this.
The most trivial of metal foil shielding or just a metal container will obscure any banknotes within any wallets or cashboxes from being RFID read remotely.
Is the second part of plan to somehow to make "de-activated" banknotes no longer legal tender ?
This would need a full strong cryptographic handshake in order to prevent attacks on legal banknotes by criminals, terrorists or pranksters, which again, none of the current cheap passive RFID chip designs e.g. EPC generation 2 ,can cope with. How can it be economical for each banknote to be as electronically complicated and expensive as, say, "chip and PIN" credit card ?
Since banks can already optically read the serial number on each note as it is passed individually across a scanner, and since this will still have to be done anyway given that bundles of banknotes cannot be read, there does not appear to be any advantage in this plan.