[Cryptography] Defeating timing attacks

[Paul Renault]

On 2017-07-16 11:55, Arnold Reinhold wrote:

> A careless repair technician can defeat a Faraday cage by failing to replace one screw (that tiny one that fell behind the desk). A malicious tech can turn an RF gasketed seam into a slot antenna with a few drops of clear nail polish. 

While I'd agree about the 'slot antenna (because of the length of the
slot), a Faraday cage doesn't need to be a perfect, seamless enclosure
to work. 

Quoting from a Gamry Instruments' web page: "the penetration of EM
radiation is limited to oscillations that have wavelengths shorter than
twice the diameter of the opening.  So a 1 cm opening allows 2 cm and
shorter wavelengths, which correspond to 150+ GHz noise."  A missing
small screw's hole, say 3mm diameter, would pass through some 500GHz or
shorter/faster wavelengths but still block all the lower frequencies.

A Faraday cage made out of metal mosquito screens would be plenty fine
for almost all computers.  I've seen some enclosing high-security
government rooms or parts of rooms.  In their case, the screen's
material was copper.  Pure, fingerprint-covered copper.

Paul

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.metzdowd.com/pipermail/cryptography/attachments/20170717/2734f7c0/attachment.html>