User's Guide

Nokia D311 PC card features
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In the infrastructure operating mode, authentication is established between a
WLAN access point and each wireless station. If a wireless station receives a
packet that has not been scrambled with a correct key, the packet is discarded.
Encrypted messages can be opened by other PC cards only if they all use the same
encryption key. In the ad hoc operating mode, authentication is established
between each wireless station.
The level of security is dependent on the length of the key: the more bits there are
in the key, the longer it takes to decrypt the information sent and the higher the
level of security.
WEP keys consist of a secret key and a 24-bit Initialization Vector. For example,
the 128-bit WEP key has a 104-bit secret key that the user can set, and a 24-bit
Initialization Vector that cannot be controlled by the user. Many manufacturers
refer to this 128-bit key as a 128-bit key, whereas some refer to it as a 104-bit key
(104+24). Both keys offer the same level of encryption and are therefore
interchangeable.
Tip: Regardless of how the WEP keys have been named, all keys are
compatible as long as their length is the same. For example, keys that are 40
bits long, always consist of 5 alphanumeric characters or 10 hexadecimal
characters.
The Nokia D311 PC card supports three key lengths: 40 (40+24), 128 (104+24),
and 152 (128+24) bits. The 40-bit key is Wi-Fi (Wireless Fidelity) compatible.
There are two types of WEP keys: shared keys and personal keys.
Shared WEP keys
Shared WEP keys are shared by all wireless stations using the network or
subnetwork; only stations that have the correct key can receive and decrypt data.
The same key is loaded into the WLAN access point. Shared keys are usually
created by system administrators, who distribute them to users.
Shared keys are network-specific, and each network can have a maximum of four
different shared keys. A WLAN access point only transmits data using the active
key, but can receive data from wireless stations using any of the four shared WEP
keys.
Tip: If you have a profile that includes more than one network, it is
recommended that you use the same shared WEP keys with all these
networks.
Because the shared WEP keys are network-specific and user-independent, they
can be saved in a file together with profiles. Users can import from a file or a SIM
card profiles that include shared keys and that have been created by their system
administrator.
Shared keys can be used as the only form of WEP security or used together with a
personal key.