This holds the eighth and last of the eight possible 192-bit Triple DES transmit encryption keys, entered as a 48-character hex string. Being the final slot, this is often left as a dedicated spare key that gets rotated into active use via cdmipIpRouteDesKey whenever another key needs to be retired, without ever needing to touch the routes actively using the other seven. A security team retiring key3 due to a suspected leak could pre-load its replacement value into key8, repoint the affected routes to key8(8), and only then clear the compromised key3 value.