Value,Name,Description,Reference
0,Reserved,,[RFC8894]
1-2,Unassigned,,
3,CertRep,Response to certificate or CRL request.,[RFC8894]
4-16,Unassigned,,
17,RenewalReq,"PKCS #10 certificate request authenticated
        with an existing certificate.",[RFC8894]
18,Unassigned,,
19,PKCSReq,"PKCS #10 certificate request authenticated with
        a shared secret.",[RFC8894]
20,CertPoll,Certificate polling in manual enrolment.,[RFC8894]
21,GetCert,Retrieve a certificate.,[RFC8894]
22,GetCRL,Retrieve a CRL.,[RFC8894]
23-255,Unassigned,,