This reminds me of a paper from a while ago that used the sound of a person typing to get their password. "acoustic keyboard emanations". It seems to be a more

This reminds me of a paper from a while ago that used the sound of a person typing to get their password. "acoustic keyboard emanations". It seems to be a more convincing paper than the OP https://www.cs.cornell.edu/~shmat/courses/cs6431/zhuang.pdf https://www.cs.cornell.edu/~shmat/courses/cs6431/zhuang.pdf