Hi. Am Freitag, 7. April 2006 19:09 schrieb MAL: > > Do you mean the server's queue or the user's mailbox? > both > I am of course assuming that courier doesn't use the contents of the > mail after it has been queued.
Courier itself never ever should use the contents of a message, only some kind of filter may do this. > Assume clueless users.. it has to be automatically > encrypted/decrypted without user intervention. So we can stop thinking about it. If a user does not have to provide key or even passphrase, every root user can do what the IMAP server does. Or simply look at the password database or modify it to gain access through IMAP. > Given that the maildir format uses only directory > structures/filenames, not the contents of files, it should be quite > possible to enable the delivery agent (can be done with maildrop) and > the IMAP server (would need an encryption patch?) to write/read > encrypted data. The key could be provided only when the services are > started, and cached in memory. Don't forget: root can read the memory. :) > The reason for this requirement is to stop server admins from reading > e-mail, to allow sensitive customer's sites to be managed by a third > party. If you don't trust root: Forget it. You will never be able to sleep at night if sensitive data is on a computer where you don't trust root! > If the above is impossible, are Linux filesystem ACLs able to > disallow access to root? No. > Does this require selinux-type extensions? I don't have experiences with that, but SElinux should be able to restrict root's access in some way. But the administrator of a system who sets this up can also revoke or modify this setup so he can always get through to your data. Just my opinion. I'm always fighting for encryption, but not inside a machine where you cannot trust root. Use disk-encryption für queue and maildirs, that prevents "hacking" by physical access of third-party. And give your customers a modern email app, that can de- and encrypt automatically. That's the right place to start thinking about privacy. cu, Bernd -- The hardness of the butter is proportional to the softness of the bread.
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