IP: New results on WEP (fwd)

[David Farber <dave@farber.net>]

>
>To: cryptography@wasabisystems.com
>Subject: New results on WEP (fwd)
>Date: Wed, 25 Jul 2001 19:13:29 -0400
>From: Matt Blaze <mab@research.att.com>
>Sender: owner-cryptography@wasabisystems.com
>
>
>Adi Shamir and his colleagues have some interesting
>new results on RC4 with a practical attack against WEP.
>With Adi's permission, I've made available a (PostScript)
>copy of a draft of his paper at:
>   http://www.crypto.com/papers/others/rc4_ksaproc.ps
>
>(Fortunately, as far as I know WEP isn't used for copy protection,
>so it's still legal to disseminate and traffic in this kind
>of information...)
>
>- -matt
>
>- ------ Forwarded Message
>
>Date: Thu, 26 Jul 2001 00:50:03 +0300
>From: Shamir Adi <shamir@wisdom.weizmann.ac.il>
>Organization: Weizmann Institute of Sciense, Faculty of Mathematics
>To: mab@research.att.com
>Subject: New results on WEP
>
>Dear Matt,
>
>WEP is the security protocol used in the widely deployed
>IEEE 802.11 wireless LAN's. This protocol received a lot
>of attention this year, and several groups of researchers
>have described a number of ways to bypass its security.
>
>Attached you will find a new paper which describes a truly
>practical direct attack on WEP's cryptography. It is an
>extremely powerful attack which can be applied even when
>WEP's RC4 stream cipher uses a 2048 bit secret key (its
>maximal size) and 128 bit IV modifiers (as proposed in WEP2).
>The attacker can be a completely passive eavesdropper (i.e.,
>he does not have to inject packets, monitor responses, or
>use accomplices) and thus his existence is essentially
>undetectable. It is a pure known-ciphertext attack
>(i.e., the attacker need not know or choose their
>corresponding plaintexts). After scanning several hundred
>thousand packets, the attacker can completely recover the
>secret key and thus decrypt all the ciphertexts. The running
>time of the attack grows linearly instead of exponentially
>with the key size, and thus it is negligible even for 2048
>bit keys.
>
>I'll appreciate your comments and suggestions. Please feel
>free to forward this email to your colleagues.
>
>
>Sincerely yours,
>
>Adi Shamir



For archives see: http://www.interesting-people.org/