WEP
- a shared 40 or 104 bits length key
- a 24 bits length initialization vector (IV) *randomly* chosen for
each emitted packet.
- a RC4 algorithm applyed on these 64/128 bits generates a stream 1
- to the clear text packet is added a CRC32, and we obtain a
stream 2
- we emit IV followed with (stream 1 XOR stream 2).
- the receiver generates stream 1 on his own, and finds back
the packet in clear text by XORing the crypted stream with stream 1
