[Cryptography] 'The intelligence coup of the century'

[Dave Horsfall]

On Thu, 13 Feb 2020, Henry Baker wrote:

> BTW, IBM mainframes had powerful radio side-channels: in the early
> 1960's, one of the programmers that worked with me used to put an
> ordinary portable radio on top of the IBM CPU so that he could
> "listen" to his program go through its paces.  Any change in the
> audio would indicate a problem with the software.

Indeed; apparently once could write programs that played music that
way.  A constant tone meant thatthe program was in a loop, etc...

Who knows what could have been leaking out, and how far?

-- Dave