Messages in this thread | | | From | "van Heusden, Folkert" <> | Subject | RE: crypted swapspace? | Date | Tue, 14 Dec 1999 16:25:27 +0100 |
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> > The most preferable way would be a crypted-filesystem wherein you > > would have a swap- file. > Well, the "hard" part about a crypted filesystem is how do > you get the > key into the system. If it's on disk, the bad guys can find > it, if you > require the operator to enter it, the operator needs to be present at > a reboot.
Well, for general-not-expected-outage; an UPS will do. It's more like the unexpected: some criminal manages to reach the server, unplugs it, etc. Ok, he'll have some expensive hardware then, but the data is at least not readable (and you're also glad you stored those backup-tapes somewhere else).
> But "swap space" is different: It is completely acceptable if the > kernel grabs a random key from the entropy pool on the first swap.
Hmmmm, that's an extremely good point! Didn't think of that. Maybe something like; generate x bytes (where x = pagesize) of random data (from entropy-pool) and do a xor for every page you're about to write down. But then; if some application swapps out 20 pages of a regular pattern; all 0x00's or whatsoever (all 0x34, all 0x8d, doesn't matter). You will be able to re-calculate back the original key. Still, this one-time key is really a fine idea!
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