Encryption & Authentication

Mar 21, 2005 4 Replies

Hi,



Please could someone clarify a few things:



With standard 802.11b/g, is it possible to use Shared key authentication, but no WEP encryption)?



Also, is it possible to use Open authentication with WEP encryption?



If so, when the only option in the configuration is to turn WEP on or off, which type of authentication does it use?



I presume the preferred option is to use shared authentication when using WEP encryption (assuming WPA is not available)?



Thanks, Joe



Joe schrieb:

Shared Key authentication uses WEP encryption. IEEE 802.11 specifies WEP encryption and Shared Key authentication (however, see below...).

802.11b/g are supersets of 802.11.

Yes, this is the default with many adapters, because WEP Shared Key authentication is a security problem (i.e. it exposes key stream that can be reused to attack WEP).

I guess this depends on the adapter (i.e. I don't know how each individual adapter handles this).

No, it is a security problem (see above).

Michael

Sure, there are several ways. WLAN standards:

- WPA (authentication & WEP encryption with dynamic key management)

- WPA2 (authentication & AES encryption

- IEEE 802.11i/x (unfinshed standards will implement several algorithms, since it is still draft I can't give no details)

The WEP authentication in boneheaded. It provides no security. (cyphertext2 = cleartext1 XOR cyphertext1 XOR cleartext2). If you set the AP to open mode it mostly means that clients can connect unencrypted. If only encrypted conenctions are allowed the AP will filter out all packets coming from client that don't know the WEP key.

In the end WEP will not secure your WLAN. If you have enough traffic it can be cracked in about 1 hour.

Thomas

Thanks for the reply.

I was only really asking the questions out of curiosity. Unfortunately I have no choice about using WEP (that or nothing).

Joe.

Thanks a lot - useful answers. Joe

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