Configuring the AP
AP-4131 Access Point Product Reference Guide 155
2.17 Mobile IP Using MD5 Authentication
Users can achieve authentication by using the MD5 algorithm with a shared
key configured into the AP and its MU. MD5 is a message-digest algorithm
that takes an arbitrarily long message and computes a fixed-length digest
version, consisting of 16 bytes (128 bits), of the original message. Users can
think of the message-digest as a fingerprint of the original message. Since
the message-digest is computed using a mathematical formula or algorithm,
the probability of an entity reproducing the message-digest is equivalent to
two people having the same fingerprints. The message-digest is the
authentication checksum of a message from a mobile MU to an AP during
the Home Agent registration process. The MD5 algorithm purpose,
therefore, prevents an MU from impersonating an authenticated MU.