Wep 40bit key

[Jim Carter]

On Sat, 15 Feb 2003, Brad Brad wrote:
> Hi, i've got my rebadged orinoco gold working fine unWEPed, however enabling
> WEP kills things.  I read that i can only have 40bit, aparently its key
> length is 5 chars though? my AP won't accept less than 10chars and calls
> that 64bit.  from my understanding 64bit is 40bit + marketing?  any ideas on
> whats happening there?  128 is also 13 char verse 26 char btw.

`iwconfig eth0 key s:abcde` is equivalent to `iwconfig eth0 key
6162-6364-65` with or without the hyphens.  Microsoft Windows XP will take
either 5 ASCII bytes or 10 hex digits without hyphens.  Your access point
probably wants you to translate your ASCII string into hex.  Or generate a
"truly" random hex string and use that both places.  `ipsec ranbits 40` is
convenient if you have it installed.  Omit the underbars that come out
every 8 bytes.

You're right that 64 bits = 40 bits + marketing.  The firmware supplements
the user-provided key with the card-dependent part of the MAC address, to
guarantee that each card on the net uses a different WEP key (if the cards
are from the same manufacturer).  Similarly with 104 + 24 = 128 bits, which
doubles the time it takes AirSnort to crack the key.

Here's my user support writeup about setting up wireless cards, with some
notes at the end about setting up your own network.
http://www.math.ucla.edu/computing/user_support/hardware/wiresetup.html

James F. Carter          Voice 310 825 2897    FAX 310 206 6673
UCLA-Mathnet;  6115 MSA; 405 Hilgard Ave.; Los Angeles, CA, USA 90095-1555
Email: jimc at math.ucla.edu  http://www.math.ucla.edu/~jimc (q.v. for PGP key)