This read-write object holds the actual WEP secret key value used for non-unicast traffic on this VLAN, though per the desc the agent always returns a zero-length string when this object is read, specifically to prevent the key from being disclosed via SNMP. An admin can write a new key here but can never retrieve the current one back out through this object, a deliberate security design choice. For example, an admin rotating the shared WEP key on a VLAN would write a new value to cwvlWlanNUcastKeyValue but would need to track the key separately, since reading it back afterward will only ever show an empty string.