Eric Hughes <hughes@soda.berkeley.edu> writes: [...]
Such a system would not be completely secure but would provide some protection for files, which is more than they get now...
The keying material for the disk should not be one key for the whole disk. The keying material could easily be one key per track without the keys growing too large.
Actually I was sort of thinking of the keying being done on a per-user basis. The user would supply a key (with the pub key kept online and the private part stored in kernel memory during the user session) that would be used for thier files and the system key would only be used to provide a secure channel between the user and the system (user encrypts thier key pair with the system key and transmits it). I have several ideas on how to close up some of the holes on the OS side, but at the moment I am trying to concentrate on finishing up the details of just the filesystem side so I can get coding. Right now I am working on making the system provide security such that the only way to get at a file is to either have the legitimate user's private key or to have the system private key and run the system as a sort of trojan horse collecting keys as users login. Having the system private key will not give you any sort of "replay" data (you will not be able to use the system key to get any past user keys or much of anything else...) and having the physical hardware without the system private key will give you nothing at all. jim