User's Manual

Doc. No.
Rev.
Date
1.00
2011-12-08
Damm Cellular Systems A/S, Denmark
TETRAFLEX
®
V7.5 MANUAL - Authentication and Encryption
TetraFlex® 7.5 Manual 3-55
Figure 3-32: Key principles
3.4.4 Backup
It is essential that the K values are kept at a safe place that means to place the programmer
key file in a safe place.
Backup should always consist of at least:
 Master Subscriber Register
 Key Register
3.4.5 Restore
If the node containing the Master Subscriber register is isolated or removed, the system will
continue to work as usual except that new terminals cannot be added to the Subscriber
register.
When using encryption/Authentication it is recommended to wait adding subscribers until the
node containing the Master Subscriber Register is available again.
Alternatively it is possible to assign another node as Master Subscriber register and add the
subscribers to this register.
After adding subscribers, the Key File (K) is read into the Subscriber Register as described
previously.
This will create a new Key Register on this node containing the K
1
values for the new
terminals.
The disadvantage of this is that when the Security Sets must be updated, both nodes must
be updated, so this method is NOT recommended
In case the node containing the Master Subscriber Register is totally lost or an exchange or
change of node for some other reason is preferred, then all Key Files (K) can be read in