>>>> I've got a encrypted partition set up under /secure. I'd like the >>>> partition to be unmounted after no-ones used it for, say, 30 minutes. [...] >>> Of course you have to already have run losesetup. "crypt" will be a >>> dir in /misc but anyone not having permissions won't even be able to >>> see any dir there. [...] >> I don't get this. If you've already provided an encryption key to >> losetup, isn't the filesystem as good as mounted? It seems to me that >> at that point encryption is no more secure than filesystem permissions. >> What are you using encryption to protect against? What is the point >> of using encryption if the filesystem is always unlocked and sitting >> in /dev/loop (even if only root has access)? > Simply that it's invisible unless in use. But there isn't any security in > any other method of auto mounting/unmounting either. If you have a script > providing the passwd to losetup, where's the security? > As far as I'm concerned, you don't have any security unless you're using a > long passphrase contained on a usb or pcmica drive which you keep in your > pocket, and which runs a script to losetup and mount the encrypted partition, > then unmounts it when the usb device is removed. Again, I think a properly designed system can easily be more secure. As I mentioned, pam_mount can mount encrypted filesystems when a user logs in and unmount them when a user logs out using the login authentication. Assuming a good authentication technique (ie: a physical token containing a maximum-entropy 256-bit key or maybe a good, long passphrase) and carefully audited software, this architecture can be made pretty secure. As I mentioned before unmounting and mounting could easily be tied to XScreenSaver for increased protection. -- Mike :wq - Linux-crypto: cryptography in and on the Linux system Archive: http://mail.nl.linux.org/linux-crypto/
