| 101 | Registration submission Submission of information for registration. |
| 102 | Asymmetric key pair request Request a trusted party to generate an asymmetric key pair. |
| 110 | Certification request Request certification of credentials and public key. |
| 111 | Certificate renewal request Request to extend the validity period of the current valid key, whose certificate is about to expire. |
| 112 | Certificate replacement request Request to replace the current certificate by a new one with a different public key (and possibly other information). |
| 121 | Certificate (path) retrieval request Request the delivery of an existing (valid or revoked) certificate, with path details where appropriate. |
| 123 | Certificate list retrieval request Request full or partial list of certificate. |
| 124 | Certificate status request Request current status of a given certificate. |
| 125 | Certificate validation request Request the CA to validate an existing certificate. |
| 126 | Certificate delivery request Request the CA to deliver a (valid or revoked) certificate to a list of recipients known to the CA or specified elsewhere. |
| 130 | Revocation request Request revocation of a party's certificate. |
| 131 | Alert request Request to put a party's certificate on alert. |
| 140 | Revocation list request Request full or partial list of revoked certificates. |
| 150 | Symmetric key request Request the delivery of symmetric keys. |
| 151 | Symmetric key discontinuation request Request discontinuation of symmetric key. |
| 152 | Asymmetric key discontinuation request Request discontinuation of asymmetric key. |
| 221 | Certificate delivery Delivery of an existing (valid or revoked) certificate. |
| 222 | Certificate path delivery Delivery of a path. |
| 224 | Certificate status notice Notice of current status of a given certificate. |
| 225 | Certificate validation notice Notice of validation of an existing certificate. |
| 231 | Revocation confirmation Confirmation of revocation of a party's certificate. |
| 251 | Symmetric key delivery Delivery of symmetric keys. |
| 252 | Discontinuation acknowledgement Acknowledgement of the requested discontinuation. |