Security and Encryption for Confluence meets compatibility requirements for Confluence Data Center which means read-only mode is fully supported.

Read-only mode is a feature administrators of Confluence Data Center can turn on during maintenance. When Confluence is in read-only mode, users may only view a page, but not create or edit them.

For more information on Confluence Data Center's read-only mode, read Atlassian's documentation.

Using Secure macro while in read-only mode

If a user tries to edit a Secure macro, they will be notified that the site is in read-only mode and the macro is temporarily disabled.

If an administrator enables read-only mode while a user is editing a Secure macro, they will be notified of the site's status and will be temporary unable to edit the macro.