Open System or Shared-key authentication

Hi all,

hope somebody knows what the difference is between the Open System
authentication and Shared-Key authentication. I'm intersted in more
detailed information and some argumentation why I should choice for
Shared-Key or Open System.

I'm told (without any argumentation) that Open System is the best
option.


Kind regards,
J.


by the way:
ofcourse I'm speaking about wireless networking with WPA-PSK using
AES.

On 26 Jan 2005 13:34:56 -0800, Richie spoketh

>Hi all,
>
>hope somebody knows what the difference is between the Open System
>authentication and Shared-Key authentication. I'm intersted in more
>detailed information and some argumentation why I should choice for
>Shared-Key or Open System.
>
>I'm told (without any argumentation) that Open System is the best
>option.
>
>
>Kind regards,
> J.
>
>
>by the way:
> ofcourse I'm speaking about wireless networking with WPA-PSK using
>AES.

WPA doesn't use open system or shared key authentication, so don't worry
about it.

Lars M. Hansen
http://www.hansenonline.net
(replace 'badnews' with 'news' in e-mail address)

> Hi all,
>
> hope somebody knows what the difference is between the Open System
> authentication and Shared-Key authentication. I'm intersted in more
> detailed information and some argumentation why I should choice for
> Shared-Key or Open System.
>
> I'm told (without any argumentation) that Open System is the best
> option.
>
>
> Kind regards,
> J.
>
>
> by the way:
> ofcourse I'm speaking about wireless networking with WPA-PSK using
> AES.

WPA-PSK usess a 4 way handshake. The PSK becomes the Pairwise Master
Key (PMK). The PMK
is used along with the mac address of both the ap and the client to
create a unique (Pairwise Transient Key)
The PTK is used in the initial start of dynamicly generated encrytion
keys. A sniffer can find out the Mac
addresses and also he can capture the authentication and using offline
dictionary attacks he may be able to crack
the passphrase. This is why it is important to not use names in the
dic, or your name or any other legible word.
This has been the only thing that has been mentioned as a weakness in
wpa-psk. So if you use a really wierd
passphrase of 20 characters or so you ought to be very safe (for now).
So I would say, open authentication lets anybody associate with the AP
although
they cant pass any data and havent a clue about what the PTK may be.
PSK using common words are riskier
than open.