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Reinaldo de Carvalho wrote:
<blockquote
cite="mid:mailman.23.1272470402.17447.cyrus-sasl@lists.andrew.cmu.edu"
type="cite">
<blockquote type="cite" style="color: rgb(0, 0, 0);">
<pre wrap="">> Is there a way to encrypt all of the Cyrus' user-specific files on the disk?
<span class="moz-txt-citetags">> </span>So that somebody breaking in -- or stealing the server -- has no access to
<span class="moz-txt-citetags">> </span>the messages (and other data) unless a user's password is also available?
<span class="moz-txt-citetags"></span></pre>
</blockquote>
<pre wrap="">Use a encrypted file system to protect data from steal. GPG is the
real solution because any server encryption suffers chicken and egg
problem.
</pre>
</blockquote>
<div align="justify">
<div align="justify"><a
href="http://www.freebsd.org/doc/en/books/handbook/disks-encrypting.html">Encrypted
file systems</a> have the disadvantage of having to be <i>manually</i>
mounted. So, a server reboot will not restore the IMAP-service
automatically. This is not a limitation of a particular implementation,
but simply an inevitable part of the requirement -- any automatic
procedure will leave the data just as open as with an unencrypted FS,
because a stolen server will repeat the procedure upon boot in
whosoever's hands it is booting. You could only hack something together
by storing the procedure (or a key-component thereof) on a <i>different</i>
system, but even then convincing (or coercing) the admin would give
access to all e-mails at once...<br>
<br>
The other disadvantage of relying <i>only</i> on the encrypted FS for
this purpose is that <i>all</i> messages are open, while the FS is
mounted, so a successful hacker (or coercer) penetrating the server at
runtime would have access to <i>everything</i>.<br>
</div>
<br>
The proposed method uses each user's own password to encrypt their
mails -- only the mailboxes of the currently-connected users would be
exposed to a hacker (or coercer).<br>
<br>
PGP, while great, is not an all-covering solution, because it requires
users -- and <i>all their correspondents</i> (!) -- to switch to PGP
as well. That's not an option for many, if only because Yahoo!'s and
Google's services don't support it. Neither do <i>any</i> of the
online merchants, for another example of a substantial source of
e-mails today.<br>
<br>
The proposed method would be entirely on the server, requiring no
cooperation from the user nor their MUA.<br>
<br>
I'm unaware of the "chicken and egg problem" <i>inherent</i> in server
encryption. Perhaps, you can expand on it? If that's what I think you
are referring to, my proposal deals with it -- newly arrived messages
remain unencrypted until the next time the user logs in. However, they
are no worse off, than while still traveling over the Internet, but the
user's <i>archives</i> are now protected.<br>
<br>
I think, my proposed method should be viewed as <i>complimenting</i>
the measures you mention. A particular setup can combine any subset of
them.<br>
</div>
<br>
Yours,<br>
<blockquote>-mi<br>
</blockquote>
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