What is a valid WEP key ?

Not everything you type as a WEP key is valid, as you might have already noticed. Here are some guidelines to ease creating valid WEP keys manually:

- One ASCII character is 8 bits, one HEX character is 4 bits.
- 64 bit (a.k.a. 40 bit) WEP code has 5 ASCII or 10 HEX characters.
- 128 bit (a.k.a. 104 bit) WEP code has 13 ASCII or 26 HEX characters.
...

In other words: 5/13/16/29 characters are needed for 64/128/152/256-bit WEP

Note: WEP encryption uses 24 bit "Initilization Vector" in addition to the "secret key" ( 40 bit for 64 bit WEP, 104 bit for 128 bit WEP, etc.). Therefore, 64 bit WEP can be refered to by some vendors as 40 bit WEP, and 128 bit can be referedo to as 104 bit, depending on the interpretation.