There have been a number of these side channel attacks, and they're all equally cyberpunk and hard to believe, e.g. this one [0] from 2014:
> We describe a new acoustic cryptanalysis attack which can extract full 4096-bit RSA keys from the popular GnuPG software, within an hour, using the sound generated by the computer during the decryption of some chosen ciphertexts. We experimentally demonstrate such attacks, using a plain mobile phone placed next to the computer, or a more sensitive microphone placed 10 meters away
With acoustic access, attacking the human directly is more advantageous. You can log the sound of every key press and differentiate between them. Then solve the resultant primitive substitution cipher - each key will have a distinct sound signature, solve the mapping. Don't need physical access to the keyboard at any point.
