The key used in encrypting the packets passed
between the AAA server and the client.This key
must match the one configured on the server.
This Object is similar to the 'caskey'.
If the 'caskey' of the 'casConfigTable' is
administratively set to zero length string,
then this key used.
Retrieving the value of this object via SNMP will
always return an empty string for security reasons.