Product manual

System description, DECT air interface
Technical Product Manual - DCT1800-GAP
TD 92093 (1/LZBNB 103 108 R4D) / 2006-03-09/ Ver.C
© 2006
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Fig. 35 IPEI, EMC and PSN
6.9 Authentication Key (K)
An important part of the security services is the authentication Key (K). It is used in the following
authentication features:
Authentication of portable part
Authentication of radio fixed part
Authentication of user
The authentication key (K) has a length of 128 bits and can be derived from the following keys
associated with the user:
User Authentication Key (UAK)
User Personal Identity (UPI)
Authentication Code (AC)
These keys may be specific to a particular DECT application or a particular authentication service.
6.9.1 User Authentication Key (UAK)
This is a secret authentication data contained within the subscriber’s (user’s) registration data. It is
uniquely associated with the particular (user) and the subscription. The UAK is held in non-volatile
memory within the portable part.
The user authentication key may be used to derive the authentication Key (K) when authentication of
the portable part or an fixed part service is applied.
If the authentication key (K) is derived from UAK, then in the portable part the UAK is associated with
either an IPUI or an IPUI/PARK pair.
Fig. 36 Derivation of K from UAK
6.9.2 User Personal Identity (UPI)
The UPI is used in combination with UAK to derive K when the user authentication service is applied.
It is usually a short value (e.g. 16 to 32 bits). The UPI is not stored in the portable part. It is entered
manually into the portable part by the user each time the user authentication service is required.
IPEI
20
bits
EMC PSN
16 bits
021
UAK
B1 process
K
022