[keithpeter]

"The processor draws different amounts of current depending on the operation, creating fluctuations that can be measured. Saving data to memory also requires a large amount of current, creating a “loud” operation."

Could you not recompile a kernel or something to make enough side channel 'noise' to jam the cpu/memory related 'signal' from your actual typing? Like the cook banging two saucepans together as Utz and the Critic talked in that flat in Prague? (Utz by Bruce Chatwin).

Heavy on battery, and might not address the pure keyboard side channel signal if I have understood the article correctly.

[korethr]

Though a fictitious example, in the book Cryptonomicon, the protagonist did a similar trick to try to counter the emissions from his computer being read. I don't know how practical that would be IRL, however. I use Gentoo on my daily driver, and even I am not compiling all the time. And a compile job small enough to run in an infinite loop without impacting your ability to get other work done might not make enough making noise, or might have enough of a pattern to it that it could be filtered out.