5 May
2016
5 May
'16
9:37 a.m.
On 2016-May-05, at 6:17 AM, Noel Chiappa wrote:
A Model 28 teletype with DND (Ca. Department of National Defence) tags on it I was working
on a couple years ago had been modified for what I can only presume to be TEMPEST
qualification.
All the standard wiring and electrical stuff - not just the current loop signal wiring but
even the basic AC line wiring for the motor and such, all the way out to the wall plug -
had been removed and replaced with shielded cable and connectors. The normal keyboard
contacts and print selection magnets were replaced with units enclosed in shielded
housings. The power line had a large noise filter in it's own RF-shielded housing.
From: Erik
Baigar
very interesting reading
If you want to see a great example of why it was important, check out the
so-called 'Berlin Tunnel':
https://en.wikipedia.org/wiki/Operation_Gold
http://www.fas.org/irp/cia/product/tunnel-200702.pdf
Some of the traffic that was intercepted was teletype traffic - which had
been encrypted. However, the equipment that connected the gear to the line
allowed a tiny electronic whisper of the original plain-text onto the line,
along with the encrypted form, and it was possible to read the plaintext off
the line with suitable gear.