[56] in The Cryptographic File System users list
Re: Protection against superuser?
daemon@ATHENA.MIT.EDU (Alex Raftis)
Thu Apr 23 21:20:08 1998
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From: "Alex Raftis" <alex@echidna.doverpacific.com>
Date: Thu, 23 Apr 1998 18:16:57 -0700
To: cfs-users@research.att.com
Subject: Re: Protection against superuser?
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On Thursday, April 23, 1998 you said:
> sometime ago I downloaded and installed cfs on my workstation. After
> testing it, I still don't get the point of cfs:
>
> In a normal Unix environment, if I want to avoid that other users read my
> files I just have to set the file-access permissions accordingly and
> that's it. Only "root" can still read my files, so I can encrypt (e.g.
> with the "crypt" command) any files I do not want "root" to read. cfs
> makes it a little more comfortable because I do not have to type a
> password for every file I want to encrypt or decrypt, but then the
> protection against "root" is lost because "root" can anytime go to my
> mounted cfs-filesystem and read everything anyway.
>
> So, am I missing something here? What's the point of cfs? How are you
> people using it?
CFS does a couple of very important things for you.
1. Root cannot even read your directories. All root has access to is the
encrypted directories, which he can't read. The plain text files are not
visible to root, at least on my OPENSTEP 4.2 installation. Thus, if you user
level permissions are set such that others can't read directories, only you
will have access.
2. CFS is secure. As far as my knowledge goes, even the U.S. Government
cannot yet break Triple DES. Even thousands of computers on the internet
working in tandem could not break Triple DES. This is opposed to the unix
"crypt" command which is as about as secure as Jenny McCarthy delivering a
singing telegram in the nude. Sure, the transport might distract you a
little, but it's not going to stop you from getting the message. Unix's
"crypt" is based on the German WW II Enigma cipher, and takes a modern
computer about a picosecond to break.
Alex Raftis
---
alex@doverpacific.com
