On Apr 4, 2007, at 03:38 , Dave Korn wrote:

On 04 April 2007 00:44, Perry E. Metzger wrote:

Not that WEP has been considered remotely secure for some time, but
the best crack is now down to 40,000 packets for a 50% chance of
cracking the key.

http://www.cdc.informatik.tu-darmstadt.de/aircrack-ptw/


Sorry, is that actually better than "The final nail in WEP's coffin", which IIUIC can get the entire keystream (who needs the key?) in log2 (nbytes) packet
exchanges (to oversimplify a bit, but about right order-of-magnitude)?


Hi Dave,

this of course is a question of how you value an attack: a key recovery usually is worth more than a decryption oracle.

To send arbitrary packets with the fragmentation attacks described in [1, Section 2.6], you need just a single (suitable) data packet. However, in order to decrypt packets, you need either 2 (connectivity to other networks that you have a host on that you can control, e.g the internet) or approx. 2^7 packets (no access to outside hosts) _per byte_ that you want to decrypt. Our method surely pays of if you want to decrypt more than a handful of packets.

Cheers,
Ralf

[1] Andrea Bittau, Mark Handley, Joshua Lackey
    The Final Nail in WEP’s Coffin
    IEEE Symposium on Security and Privacy 2006,
    http://doi.ieeecomputersociety.org/10.1109/SP.2006.40
---------------------------------------------------------------------
The Cryptography Mailing List
Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]

Reply via email to