[hinkley]

Adi Shamir, the S in RSA, has done tons of work on side channel analysis, especially of hardware crypto, for decades. Timing attacks, voltage attacks, EM, you name it.

So it's not unknown. But as a counterpoint I had a shocking moment in the 90's when I learned that Faraday Cages (to prevent TEMPEST attacks) were being designed with a second Faraday cage inside them to protect the light bulbs.

Seems that the interference between a CRT and a fluorescent bulb are sufficient that you can detect information on the power lines leading into the room. So they caged the bulbs to keep them magnetically isolated from the computers.