| Sender | User who has permission to send secured emails to recipients via Secure Email interface. |
| SSN | Social Security Number aka. Personal Identity Code/Number |
| Recipient | User who receives secured email from Sender; has permission to HTTPS interface. |
| D-Center | Administrator Web GUI. Provides system and instance specific configuration possibilities. |
| D-Envelope | A Sender user within the organization can use D-Envelope to send secured email to an external user. D-Envelope offers HTTPS Interface where Recipient (external user) can read messages. |
| D-Compose | HTTPS Interface where Sender outside of the organization can start the secure email conversation. |
| Secure Email | Name for the gateway-based email encryption security solution. |
| Secure Extension | Mark for the Secure Email to process the message confidentially. Typically the extension is appended into the recipient’s email address (eg. ".s"). |
| Security level | The encryption level that is used to send a confidential message to the recipient. Defines the overall level of security and required authentication methods for opening the secure message. |
| ST-IV | Refers to Finnish national protection level which is comparable to the EU level: RESTREINT UE/EU RESTRICTED |
