[SOLVED] ASCII to HEX offline generator for WEP connection

jelezarov · 05-10-2009, 01:47 AM

Hi,
i'm a happy Slackware 12.2 user on a HP-Mini 2140 netbook. All works just fine including the wireless connection. The only problem is, when traveling, how can i connect to WEP enabled AP with knowing just the passphrase. With WPA i just enter the passphrase in wicd-client (using wpa_supplicant) and i'm connected. I found a couple of online ascii to hex generators (like http://www.powerdog.com/wepkey.cgi) for different WEP encryptions (64,128 etc), but i cannot use it offline.
Is there a possibility with a script, or a program to convert the passphrase to HEX?
for example the phrase "my_wireless" in 64 bit key is 6620AF017C according to that site, and that's exactly what the router wanted.

Thanks in advance!

Hangdog42 · 05-11-2009, 11:36 AM

If you're using wicd, you can enter a WEP passphrase in the same place you would enter a WEP hex key. You just have to use the drop-down to tell wicd it is the passphrase. Along similar lines, if you use iwconfig to set the configuration, you would just use the s: prefix like this:

iwconfig wlan0 key s:WEPPassphrase

So in other words, you never need an ascii to hex converter.

jelezarov · 05-13-2009, 04:48 AM

Thanks for the reply.
Of course i tried that already. The problem is - wicd can't connect, the report from iwconfig is "Error for wireless request "Set Encode" (8B2A)". I searched Google and that appears as common problem. As i understood there is something to do with the length of the passphrase and the used encryption (64 or 128 bit).
And from "man iwconfig" comes little bit frustrating:
"You can also enter the key as an ASCII string by using the s: prefix. Passphrase is currently not supported."
Is it not the same ascii string and a latin passphrase? Anyway it doesn't work.
Any help appreciated.

Hangdog42 · 05-13-2009, 07:44 AM

Quote:

Is it not the same ascii string and a latin passphrase?

I always thought so, and I've successfully connected to access points using a latin "passphrase". I'll have to do some digging and see if I can find something that suggests there is a difference between and ascii string and a passphrase for WEP.

In the meantime, check out the xxd command, which is part of Slackware, as it will convert an ascii file to a hex file. It is a little weird (and I haven't been able to get it to accept input from a command line) but it might do the trick for you.

jelezarov · 05-14-2009, 01:57 PM

I have read something about that in the linuxquestions.org forums for programmers, and i thing maybe WEP uses a different algorithm. I tried with xxd:

Code:

$ echo my_wireless | xxd
$ 0000000: 6d79 5f77 6972 656c 6573 730a            my_wireless.

which gives exactly hex output, but unfortunately not the expected result (with 64 bit encryption is 6620AF017C, and with 128 bit is 72AA25CD43364D09986BF0B5B9).

Anyway i found a temporary solution - the site http://tv.latinsud.com/wepconv.html - that's all JavaScript and easy to use it offline. The fields "passphrase (prng) -> Hex 64" and "passphrase (md5) -> Hex 128" are the solution for passphrase to HEX for WEP conversion at least for my router. I will try to test that with some other routers.

I thing it would be very nice if someone can translate that JavaScript to C, so that this can be compiled and (maybe?) integrated in some wireless-client program like wicd.

EDIT:
Accidentally i found in the google cache for one german site a link which contains the C code and a Makefile for a program, named lwepgen which does exactly what i wanted.
Here it is: http://dslinux.gits.kiev.ua/tags/ucl...d-ons/lwepgen/
It works just fine, at least for me.

EDIT (08.02.11):
Recently i needed the lwepgen and it seems that this is not working corect anymore - i supose because of the changed openssl libraries during the system updates. The new and best working solution is this litle script based on openwrt wiki. This can be placed somewhere in $PATH and invoked with parameter the string that need to be converted:

Code:

#!/bin/bash
echo -n "$1 (64-bit) : "
echo -n $1 | hexdump -e '5/1 "%02x" "\n"'
echo -n "$1 (128-bit): "
echo -n $1 | hexdump -e '13/1 "%02x" "\n"'