|
Authored by: Anonymous on Monday, September 10 2012 @ 12:15 PM EDT |
Yes, there was a big stink in the early 1960's when somebody demonstrated that
they could read signals radiating from shielded Teletype circuits that were
several yards away. The US Navy made a big push for "Tempest"
protection on all classified circuits which changed external signals from 135V
at 60ma, to +/- 7V at 1ma. I was still repairing equipment that had been plugged
into the wrong circuit in early 1977, just before I was discharged. (This
information was declassified in 1993, along with all records from Vietnam.)
Of course the same problem exists for RFID cards, like those embedded in US
passports. They can be read from up to 100 yards away with off the shelf
equipment. Yes, even the Pringles cans for the antenna came off a shelf at the
grocery store.
[ Reply to This | Parent | # ]
|
|
|
|
|