"Unsupported TKIP Group Cipher key length"

Jouni Malinen jkmaline
Sat Jun 4 19:12:33 PDT 2005

On Thu, Jun 02, 2005 at 12:28:37AM +0200, Eric wrote:

> Ok, here's what -d gives:

> WPA: RX message 3 of 4-Way Handshake from 00:0e:9b:99:1a:38 (ver=1)
> WPA: IE KeyData - hexdump(len=24): dd 16 00 50 f2 01 01 00 00 50 f2 02
> 01 00 00 50 f2 02 01 00 00 50 f2 02

The AP is clearly advertising TKIP as the group key in the WPA IE.

> WPA: RX message 1 of Group Key Handshake from 00:0e:9b:99:1a:38 (ver=1)
> WPA: Unsupported TKIP Group Cipher key length 13 (13).

However, it tries to send a group key message with 13-byte key whereas
TKIP key should be 32 bytes. Looks like the AP is just broken.

> A friend with an hostap compatible card was able to associate to the
> AP with WPA. Maybe this is somehow a problem with madwifi.

It would be interesting to get wpa_supplicant debug log (with -dd) from
both the case with madwifi that failed and the case with Host AP driver
that managed to complete association. It would also be useful to get
wireless sniffer log showing both of these negotiations.

Jouni Malinen                                            PGP id EFC895FA

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