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

["Joshua Wright" <Joshua.Wright@xxxxxxx>]

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