An anonymous reader asks: "Microsoft Windows, from 2000 forward (except ME) offers secure certificate and private storage at the OS level in what is called a protected store. Offline, it's encrypted by a combination of the user's password and a session key stored on the filesystem. When the OS is running, the private keys stored are available to the logged in user, optionally encrypted with another password. The keys are stored in protected memory, so no applications can access them without going through the Microsoft CAPI calls. This code also is FIPS 140-1 level 1 (the best one can get for software cryptography modules) compliant." Does any other OS provide this kind of feature at the OS-level? If so, who? If not, why?