Interesting People mailing list archives

"the net"... campus-type links, and conceptualizing remote data


From: David Farber <dave () farber net>
Date: Tue, 15 Sep 2009 22:26:07 -0400



Begin forwarded message:

From: "Steven M. Bellovin" <smb () cs columbia edu>
Date: September 15, 2009 8:23:14 PM EDT
To: dave () farber net
Subject: Re: [IP] Re: "the net"... campus-type links, and conceptualizing remote data

The 802.11 WEP protocol is a security disaster.  Even in the climate of
the early 1990s -- and WEP uses RC4, which if I recall correctly didn't
come about until circa 1994 -- it has a number of serious, and mostly
avoidable, mistakes.  Put bluntly, it was badly designed in ways that
were avoidable even with the knowledge and the outlook of the time.
And as someone who was doing security and crypto back then, I'm very
well aware of the attitudes towards security prevailing then.

WEP has three serious weaknesses; two of them were avoidable, even
given its goals and the knowledge of the time.

The problem that has gotten the most attention is the cryptographic
weakness of RC4, especially against related key attacks.  This was not
knowable then.  Indeed, given its efficiency, it would have seemed a
natural choice.

However -- and this certainly was knowable -- RC4 is a stream cipher,
and as such a fundamentally bad choice for encrypting datagrams.
I'll skip the details; see the 2001 paper by Borisov, Goldberg, and
Wagner on 802.11 insecurity.  Basically, though, this was a very
avoidable mistake.

The biggest problem, though, is the lack of key management, which in
turn stems from lack of much consideration of an operational model.
How, in an organization of any size, can you simultaneously roll all of
the keys?  I'll also note that the lack of key management exacerbates
the other two problems.  I'm told that omitting key management was an
explicit design decision by the committee, because it wasn't their
problem; on the other hand, they also omitted the usual accommodations
to a key management protocol, such as an over-the-wire keyID.




-------------------------------------------
Archives: https://www.listbox.com/member/archive/247/=now
RSS Feed: https://www.listbox.com/member/archive/rss/247/
Powered by Listbox: http://www.listbox.com


Current thread: