How about a variation on A:
'You'll only be able to see this if you have permission to see the project's embargoed security information'
(When the message is outward facing to a user)
or
'Users will only be able to see this if they have permission to see the project's embargoed security information'
(When the message is for someone changing settings for their project)
How about a variation on A:
'You'll only be able to see this if you have permission to see the project's embargoed security information'
(When the message is outward facing to a user)
or
'Users will only be able to see this if they have permission to see the project's embargoed security information'
(When the message is for someone changing settings for their project)