Why I Stopped Trusting SSH Key Files

Earlier today I added my iPhone as an authorized device to a server, and the way I did it is worth writing about — because it's quietly one of the best security upgrades you can make with zero ongoing effort. The key I used never touched a disk, can't be copied off my phone, and only works after Face ID says so. Here's why that matters, and why these keys beat almost everything else people use to…