Asus WL-100GE User Manual page 33

Chapter 3 - Reference
64/128bits versus 40/104bits
You may be confused about configuring WEP encryption, especially when
using multiple wireless LAN products from different vendors. There are two
levels of WEP Encryption: 64 bits and 128 bits.
Firstly, 64 bit WEP and 40 bit WEP are the same encryption method and can
interoperate in the wireless network. This lower level of WEP encryption uses
a 40 bit (10 Hex character) as a "secret key" (set by user), and a 24 bit
"Initialization Vector" (not under user control). This together makes 64 bits
(40 + 24). Some vendors refer to this level of WEP as 40 bits and others refer to
this as 64 bits. Our Wireless LAN products use the term 64 bits when referring
to this lower level of encryption.
Secondly, 104 bit WEP and 128 bit WEP are the same encryption method and
can interoperate in the wireless network. This higher level of WEP encryption
uses a 104 bit (26 Hex character) as a "secret key" (set by user), and a 24 bit
"Initialization Vector" (not under user control). This together makes 128 bits
(104 + 24). Some vendors refer to this level of WEP as 104 bits and others refer
to this as 128 bits. Our Wireless LAN products use the term 128 bits when
referring to this higher level of encryption.
ASUS WLAN Card 33