I am developing mdm server and I have a problem with one of enrollment steps. The problem is scep step. I implement a scep server which handles Device CACert request and sends our server certificate in der format. After that, device sends encrypted and signed csr.
But I can not verify signature of message. I think device creates a self-signed-certificate and sign message with it. We think that because signature certificate's common name is changing each "PKIOperation" request. But we must verify this signature because of security.
For example in each 3 enrollment request, certificate of csr signature changes. Their common names are:
CN=6E4F65AD-1E64-4E4D-A96E-2039EB140041
CN=2E33C2CC-14B8-47AC-938B-DCC7F8DA8715
CN=6817ED48-AB79-4FF0-A1A9-42C2AC303672
Note: The other steps of enrollment device sign messages with proper certificate and I can verify them. Only scep PKIOperation request is my problem. Is there any profile flag to set or something to solve this problem?