Next, I created a pair of key files on my remote server to use, so I didn't have to supply a password each time. (howtogeek.com)
However, without encryption keys the files could not be accessed. (newlawjournal.co.uk)
Here we have the key security system, consisting of a round cardboard key tag and key file box — total investment in 1970 dollars, $ 10 for an unlimited supply of listings. (remonline.com)