[Cryptography] Hacking spread spectrum clocking of HW ?

[Bob Wilson]

>>> In the US, for example, even amateur radio operators otherwise allowed
>>> to do way more than the general public aren't necessarily allowed to
>>> transmit spread spectrum outside certain spreading codes.
>> Australian amateurs are allowed to use SS (and I have) provided the
>> authorities have been notified of the spreading code (which sorta defeats
>> the purpose);
> Depends on what you think the purpose is.  If it's to communicate through noisy channels, or just to experiment to improve or even just personally understand the technology, or to provide a public service - then it's within the ambit of the amateur services, at least as they are defined in the US.  If it's defined to include secret communications, it's definitely outside the US definitions.
>
>> we can also use crypto, for sensitive search and rescue
>> messages (and I have).
> I'm not sure that's ever permitted in the US under any circumstances.
>
>                                                         -- Jerry

In the US hams can encrypt under exactly one specified circumstance: 
Control of a space station, meaning a radio station on a satellite. That 
is presumably to keep "outsiders" from taking over control. In general a 
US ham cannot transmit anything intended to conceal information. (That 
exception is the basis for a question frequently appearing on ham 
license exams.)

Back during and at the end of WWI, the US Navy wanted control over all 
broadcasting. That by itself has little to do with cryptography, but a 
combination of that desire implying limiting what hams could do and fear 
that uncontrolled radio operations could include spying for foreign 
powers leads to this denial, which is a connection to crypto. And it 
might explain why this restriction is not found (so far as I know) 
outside the US. So spread spectrum cannot be used to conceal anything. 
But the FCC rules governing the amateur service specifically justify the 
existence and encouragement of the service in large part based on the 
progress in communication coming from hams experimenting and developing 
new techniques, hence exceptions for experiments intended to improve 
technology.

It is hard to write enforceable rules that say you can do X but not if 
your intent is to accomplish Y, resulting in very specific statements 
about what you can and cannot do: That implies they are soon obsolete, 
hence need revision from time to time, and that is definitely what has 
happened with respect to spread spectrum use by hams.

Bob Wilson (WA9D)
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