[Cryptography] Regulations of Tempest protections of buildings

[Florian Weimer]

* Perry E. Metzger:

> On Sun, 2 Apr 2017 17:48:54 +0200 mok-kong shen
> <mok-kong.shen at t-online.de> wrote:
>> I wrote previously in a  follow-up to a thread that I vaguely
>> remember to have read
>> that in US a permission is needed for Farady shielding of rooms, 
>> whereupon a few
>> readers doubted its correctness. I have just succeeded to again
>> find the source:
>> 
>> A. Stanoyevitch, Discrete Structures with Contemporary
>> Applications. CRC Press,
>> 2011. On p.301 there is:
>> 
>>       Buildings can be fitted using a special insulation procedure
>>       that protects against tempest devices, but any company or
>>       individual in the US who has this insulation must first
>>       obtain a license from the federal Government.
>
> Although I believe that this book makes such a claim, and that
> the author likely believed it to be true, I'm afraid I do not believe
> there is in fact any law whatsoever that prohibits putting foil or
> metal mesh in your walls.

Such an ad-hoc shielding would not be compliant with the TEMPEST
specifications, which do not seem to be available to the general
public.  So the quote may be phrased awkwardly, but could still be
substantially true.