Nokia C110 User Manual page 40

To provide secure communication over the wireless LAN, the Nokia C110/C111
offers the Wired Equivalent Privacy (WEP) security feature. WEP uses the RC4
algorithm with an up to 128-bit key. The algorithm provides for security via two
methods: authentication and encryption. Authentication is the means by which
one wireless station is verified to have authorization to communicate with a
second station in a given coverage area.
In the infrastructure mode, authentication is established between an 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 wireless LAN cards only if they all use the same encryption key.
In the ad hoc mode, authentication is established between each wireless station.
The WEP feature offers a security level comparable to that of wired networks. 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 104-bit WEP key has a 104-bit secret key which the user can set, and a 24-bit
Initialization Vector that cannot be controlled by the user. Some manufacturers
refer to the 104-bit key as a 104-bit key, whereas others refer to it as a 128-bit key
(104+24). Both keys offer the same level of encryption and are therefore
interoperable.
Other manufacturer's 128-bit keys may not be compatible with the 128-
bit key (128+24) used with the Nokia C110/C111. Instead, with the Nokia
C110/C111 you may need to use the 104-bit key (104+24) to ensure
compatibility with other manufacturer's 128-bit keys.
There are two types of WEP keys: shared keys and personal 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 access point. Shared keys are usually created by
system administrators, who distribute them to users. In the ad hoc operating
mode, the person who is creating the ad hoc network decides on a password and
then distributes it to others. The system uses this password to create a shared
WEP key.
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