Dear Dennis...
EN-Genius Network's Dennis Feucht answers your design
queries in his new Circuit Design Clinic!
April, 2008
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EN-Genius Network presents a new, interactive
analog design service to readers! Send us your design questions (with
relevant data; schematics in JPEG or GIF, please) for some free
engineering advice from EN-Genius Network's circuit
consultant, Dennis Feucht, on how you might solve a design problem or
improve circuit performance. Submissions may be edited for clarity or
brevity, and submitters and their email addresses will remain anonymous
(unless otherwise indicated). Please send your questions to Dennis here.
How To Cheat At Deploying And Securing RFID
by Dennis L Feucht
by Paul Sanghera, et al, Published by Syngress Elsevier
ISBN 13: 978-1-59749-230-0, paperback, 362 pp, $49.95, December 2007
This book covers technical and security basics of RFID. It is apparently the result of a group effort, and my reading of it would place it at a technician level. The presentation of material includes a few formulas here and there, all using pre-calculus mathematics. Yet there is something about this book that might be of interest to engineers: the non-technical aspects of RFID.
But first, a quick sweep through the technical contents. It is roughly the same subject-matter as in the previously reviewed engineering book, The RF in RFID by Dobkin, but presented so that an intelligent high-school student could read and understand it. Various practical aspects are also presented, including RFID labels and printers for them, and RFID peripherals more generally, and how to fix them.
Then beginning with chapter 12 (p 243) titled, “RFID attacks: Tag Encoding Attacks,” the fun begins. One of the authors, from Canada, is a high-level hacker. The book describes Brad “RenderMan” Haines of Alberta as “one of the more visible and vocal members of the wardriving community, appearing in various media outlets and speaking at conferences …his involvement through the years with the hacking community, sometimes to the attention of carious [sic] Canadian and American intelligence agencies. A firm believer in the hacker ethos and promoting responsible hacking and sharing of ideas…” You get the idea; a mature hacker has written the rest of the book, and it is interesting, though it is not directly about RF circuits; it is about social uses and misuses for them.
Two hacking projects are described, both to reverse engineer the SpeedPass RFID tags by Exxon Mobil’s filling-station RFID for trucks. A Johns Hopkins group beat Haines’ group, with superior resources, to the successful hack of the 40-bit encrypted code and encoding format. Phil Koopman, a computer science professor at CMU had cautioned in e-mails about the vulnerability of cheap RFID technology. (Koopman, a former stack-machine architect known to the Forth community of the 1980s, has a great story from his younger days, when he was a “submarine driver” in training, doing some clever technical tricks and popping his sub up in the middle of a US Navy carrier group where it was thought too protected for that to be possible.) The topic leads into discussion of consumer product tags in a cautionary tone, about how clothing tags can be used by thieves to identify wearers by the quality of clothing worn. The use of tags in warehousing and item tracking -- basically as a replacement for bar codes -- dispels some misinformation about them but, overall, raises more ominous possibilities. The story of the Rheinberg, Germany supermarket of the future is told, with a cameo appearance by leading anti-RFID consumer privacy activist, Katherine Albrecht of CASPIAN (http://www.spychips.com and http://www.nocards.org or http://www.nocards.com).
The discussion ranges over inclusion in European currency of RFID in every bill; “Thieves would have a field day with this new technology” using RFID scanners to locate people carrying plenty of money. Similar problems of security and privacy apply to the US Passport RFID, though the volume of concern raised has caused the RFID information to be encrypted and the encryption key put in the bar code of the passport. This requires that the passport be scanned for the RFID information to be decrypted. (But then, why bother with the RFID?) Additional related topics cover chip cloning and fraud, disruption through invocation of the “kill” command from a high-power transmitter which could “kill every tag in the place, causing a large level of retail chaos.” The larger point is that if tag RFID function is disrupted, by whatever means and for whatever reason, is there any backup like there was in the printed code of the bar code system?
Subsequent chapters cover RFID security solutions, using middleware, and finally, the management of RFID. Overall, the last few chapters on RFID hacking were the most interesting and illuminating to me. Other engineers might also find some of it interesting.
Buy the book for this section, then give it to a deserving home-schooling youth to learn about the physics and electronics of RFID.
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