Regarding security endpoints, you have 2 opportunities :
- Newer phones are using more an existing Mafufacturing Installed Certificate , this is the MIC
- Meanwhile , old phones will use a Locally Significant Certificate ( LSC) which will be installed by the Certificate Authority Proxy Function (CAPF)
As LSC must be a transaction between the Ip phone and the CAPF , here is the process as it is issued :
- IP Phone generates a public/private key pair
- A TLS Session is established with the CAPF Service and the keys and identity are sent from the phone to CAPF
- The CAPF Service creates and sends an LSC to the phone
- The IP Phone installs the LSC
Also for info, the CAPF Service must be in the phone CTL file , which is downloaded from the TFTP when the phone boots .