Proceedings Article | 17 April 2006
KEYWORDS: Computer security, Magnetism, Near field, Antennas, Radar, Information security, Receivers, Global Positioning System, Digital signal processing, Modulation
From historical perspective, the recent advancements in better antenna designs, low power circuitry
integrations and inexpensive fabrication materials have made possible a miniature counter-measure against
Radar, a clutter behaving like a fake target return called Digital Reflection Frequency Modulation (DRFM).
Such a military counter-measure have found its way in the commerce as a near field communication known
as Radio Frequency Identification (RFID), a passive or active item tag T attached to every readable-writable
Smart Card (SC): Passports ID, medical patient ID, biometric ID, driver licenses, book ID, library
ID, etc. These avalanche phenomena may be due to the 3rd Gen phones seeking much more versatile &
inexpensive interfaces, than the line-of-sight bar-code optical scan. Despite of the popularity of RFID, the
lacking of Authenticity, Privacy and Security (APS) protection restricted somewhat the wide spread
commercial, financial, medical, legal, and militarily applications. Conventional APS approach can
obfuscate a private passkey K of SC with the tag number T or the reader number R, or both, i.e. only T*K
or R*K or both will appear on them, where * denotes an invertible operation, e.g. EXOR, but not limited to
it. Then, only the authentic owner, knowing all, can inverse the operation, e.g. EXOR*EXOR= I to find K.
However, such an encryption could be easily compromised by a hacker seeking exhaustively by
comparison based on those frequently used words. Nevertheless, knowing biological wetware lesson for
power of pairs sensors and Radar hardware counter-measure history, we can counter the counter-measure
DRFM, instead using one RFID tag per SD, we follow the Nature adopting two ears/tags, e.g. each one
holding portions of the ID or simply two different ID's readable only by different modes of the
interrogating reader, followed by brain central processor in terms of nonlinear invertible shufflers mixing
two ID bits. We prefer to adopt such a hardware-software combined hybrid approach because of a too
limited phase space of a single RFID for any meaningful encryption approach. Furthermore, a useful
biological lesson is not to put all eggs in one basket, "if you don't get it all, you can't hack it". According
to the Radar physics, we can choose the amplitude, the frequency, the phase, the polarization, and two
radiation energy supply principles, the capacitance coupling (~6m) and the inductance coupling (<1m), to
code the pair of tags differently. A casual skimmer equipped with single-mode reader can not read all. We
consider near-field and mid-field applications each in this paper. The near-field is at check-out counters or
the convey-belt inventory involving sensitive and invariant data. The mid-field search & rescue involves
not only item/person identification, but also the geo-location. If more RF power becomes cheaper &
portable for longer propagation distance in the near future, then a triangulation with pair of secured readers,
located at known geo-locations, could interrogate and identify items/persons and their locations in a GPS-blind
environment.
