- Van Eck phreaking
Van Eck phreaking is the process of
eavesdropping on the contents of a CRT display by detecting itselectromagnetic emissions. It is named after Dutchcomputer researcher Wim van Eck, who in1985 published the first paper on it, includingproof of concept .cite journal | author=Van Eck, Wim | title=Electromagnetic Radiation from Video Display Units: An Eavesdropping Risk? | journal=Computers & Security | volume=4 | year=1985 | pages=269–286 | url=http://jya.com/emr.pdf | doi=10.1016/0167-4048(85)90046-X ]Phreaking is the process of exploitingtelephone network s, used here because of its connection to eavesdropping.Van Eck
phreaking might also be used to compromise the secrecy of the votes in an election usingelectronic voting . This caused the Dutch government to ban the use of NewVotecomputer voting machine s manufactured bySDU in the 2006 national elections, under the belief that ballot information might not be kept secret. [ [http://www.iht.com/articles/ap/2006/10/30/europe/EU_GEN_Netherlands_Voting_Machines.php Dutch government scraps plans to use voting computers in 35 cities including Amsterdam (Herald tribune, 30. October 2006)] ] [ [http://www.heise.de/english/newsticker/news/80302 Use of SDU voting computers banned during Dutch general elections] (Heise, October 31. 2006)]Basic principle
Information that drives the
video display takes the form ofhigh frequency electrical signals. Theseoscillating electric currents createelectromagnetic radiation in the RF range. Theseradio emission s are correlated to thevideo image being displayed, so, in theory, they can be used to recover the displayed image.CRTs
In a CRT the image is generated by an
electron beam that sweeps back and forth along thescreen . The electron beam excites the phosphor coating on themonitor glass and causes it to . The beamintensity determines the intensity of thepixel (see CRT for a detailed description). The electron beam is deflected by severalelectromagnetic coil s. The voltage in the coils ismodulated at ahigh frequency and contains information related to the video image. (Error: These coils carry signals controlling beam deflection only, not beam intensity modulation, and can not, in principle, radiate any video display information.) These high frequency,high voltage signals create electromagnetic radiation that has, according to Van Eck, "a remarkable resemblance to a broadcast TV signal". What these radiated signals lack is thesynchronizing portion of the TV signal. (The deflection coils mentioned above would emit "only" synchronization signals. The vertical sync is so low-frequency that its probably would not be significantly detectable and would have to be externally recreated.) By supplying externalsynchronization , the radiated signal can be displayed on anothertelevision .In the paper, Van Eck reports that in
February 1985 a successful test of this concept was carried out with the cooperation of theBBC . Using a van filled with electronic equipment and equipped with a VHFantenna array , they were able to eavesdrop from a "large distance".LCDs
In April 2004 new academic research has revealed that flat screens and laptop displays are also vulnerable to an
FPGA -driven electromagnetic eavesdropping. The required equipment for espionage was constructed in a university lab for less than 2000 US dollars.cite journal | author = Kuhn, M.G. | year = 2004 | title = Electromagnetic Eavesdropping Risks of Flat-Panel Displays | journal = 4th Workshop on Privacy Enhancing Technologies | pages = 23–25 | url = http://www.cl.cam.ac.uk/~mgk25/pet2004-fpd.pdf ]Countermeasures
Countermeasure s are detailed in the article onTEMPEST , the NSA's standard on spy-proofing digital equipment. One countermeasure involves shielding the equipment to minimizeelectromagnetic emissions. Another method, specifically for video information,scramble s the signals such that the image is perceptually undisturbed, but the emissions are harder to reverse engineer into images. Examples of this include low pass filteringfonts andrandom izing theleast significant bit of the video data information.Limited use
Van Eck phreaking potentially offers non-proximate eavesdropping options without the interested person having to compromise the affected system's hardware or software. Some may dismiss this possibility as the domain of "tin-foil hat" wearers, but Wim van Eck himself demonstrated a working model of this technology for a paltry $15 in 1985.
In popular culture
*In
Neal Stephenson 's 1999 novel "Cryptonomicon ", Van Eck phreaking (of a laptop LCD) serves as a significantplot device .
*Van Eck phreaking was referenced directly in the "Numb3rs " season one episode "Sacrifice", on an LCD flat screen rather than a CRT monitor.
*Phillip Finch 's 1995 novel "f2f" features the main character Ellis Hoile building a Van Eck scanner, and the device is used to finalize the plot of the book.
*In a fifth season episode of "Alias", a character suggests that they use Van Eck phreaking.
* Is often referred to inCharles Stross ' novel "The Atrocity Archives " as a danger when viewing classified information.ee also
*
TEMPEST --(US government standards for limiting electric or electromagnetic radiation emanations from electronic equipment)
*RINT --(Radiation INTelligence, military application)
*Election fraud References
External links
* [http://upe.acm.jhu.edu/websites/Jon_Grover/page2.htm Van Eck phreaking]
* [http://www.erikyyy.de/tempest/ Tempest for Eliza] is a program that uses your computer monitor to send out AM radio signals. You can then hear computer generated music in your radio.
* [http://www.lightbluetouchpaper.org/2006/03/09/video-eavesdropping-demo-at-cebit-2006/ Video eavesdropping demo at CeBIT 2006] by a Cambridge University security researcher
* [http://eckbox.sourceforge.net eckbox] – unsuccessful or abandoned attempt in spring 2004 to build an open-source Van Eck phreaking implementation
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