Handover mechanisms in next generation heterogeneous wireless ...

PROXY BASED AUTHENTICATION LOCALISATION SCHEME FOR HANDOVER
networks, and can provide the neighbour network identifier list to the HAAA along with
the MH’s request for the FAT.
Following the successful attachment to the serving network sAN, the MH sends a FAT
Request with an encrypted mobile nonce ( K ( N m ) ) to its HAAA to request the FATs
E hm
via the sAN. The sAN provides an identifier list of its Neighbour Access Networks
(NAN) NAN ID �AN , AN ,..., AN �
_ s 1 2 t that includes the identifier of every nearby AN
( AN t ). The sAN forwards the FAT request along with the identifier list NAN _ IDs
to
the MH’s HAAA.
Upon receiving the FAT request, the HAAA generates a server nonce ( N s ), which will
be encrypted in the generated FAT along with other security credentials as shown in
Equation 6.1. The server nonce N s will later be provided to the FAP, and used as a
challenge to verify the MH’s identity. Since N s is generated for a specific AN, the
HAAA needs to find the associated FAP according to the AN’s identifier. The HAAA
issues a FAT for every AN included in the neighbour access network identifier list
NAN _ IDs
:
FAT m s p
� E ( ID , N , PID , SQN,
LAK,
MAC)
(Equation 6.1)
K hp
Each FAT encloses the information about the MH’s identity ( ID m ), the server nonce
( s N ) issued by the HAAA, the Pseudonym Identity (PID) of the FAP ( PID p ), the
sequence number (SQN), the Local Authentication Key (LAK) for the FAP and the
Message Authentication Code (MAC) to be used for verifying the MH’s identify.
For security concerns, the server nonce N s issued will be varied for different FAPs so
that different access networks would have different security contexts. The FAP’s PID p
is derived using the secret splitting method described in [101]:
PID � h(
K || N ) � ID � N
(Equation 6.2)
p
hp
s
p
s
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