The syntax for the message-security element is as follows:
<!ELEMENT message-security (message+, request-protection?, response-protection?)>
Table 8–5 message-security Element| Element name | Occurrences | Description | Type | 
| message | 1 or more | Describes the methods or operations to which the security requirements apply | |
| request-protection | 0 or 1 | Describes the authentication requirements applicable to a request | |
| response-protection | 0 or 1 | Describes the authentication requirements applicable to a response |