Ethereal-users: RE: [Ethereal-users] WEP ICV (integrity check value)

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From: "Joshua Wright" <Joshua.Wright@xxxxxxx>
Date: Thu, 24 Apr 2003 13:43:31 -0400
guoquan,

>     i have a question about reading wireless 
> data (802.11b) using ethereal. i suppose that 
> plain text and ICV should be encrypted before 
> being transmitted. But why is ethereal able to 
> display its ICV value? thanks
> 
> example:
> WEP ICV: 0x12345678 (not verified)

The ICV is not encrypted, it is just a CRC-32 that is appended to the end of the frame, based on the encrypted payload.

-Joshua Wright
Senior Network and Security Architect
Johnson & Wales University
Joshua.Wright@xxxxxxx 
http://home.jwu.edu/jwright/

pgpkey: http://home.jwu.edu/jwright/pgpkey.htm
fingerprint: FDA5 12FC F391 3740 E0AE BDB6 8FE2 FC0A D44B 4A73