"linked to national security" is correct and usable in written English.
You could use it to refer to something that affects, or is related to, national security. For example: "The new laws proposed are closely linked to national security."
Unlike its US counterpart, GCHQ is entitled to engage in spying relating to economic matters, but only if it is linked to national security issues.
If history is a guide, experts say, the nature of the charges against Rezaian are likely trumped up – and linked to national security.
Aware of those sensitivities, the proposal excludes railroads, oil and natural resources, electricity, and water and sewage -- areas that are either linked to national security or that might inflame national resentment if opened to foreigners.
But the broader impact may be felt internally, since nonproliferation decisions have been inextricably linked to national security imperatives.
Another recommendation the government has rejected is the justification of "economic well-being", linked to national security, as a purpose for which some of the powers set out in the bill can be used.
Elsewhere in this paper we have argued that there exists an ethically and morally-based concern about the state of human rights in the less developed world among most of the Northern world, and an action on this issue almost always is linked to national security and interest of the powerful states.
Sometimes, security agency and bureau officials accuse the smaller agencies of exaggerating links to national security threats in their own cases when pushing for access to the security agency's surveillance capabilities.
Officials from the other agencies say that if a link to national security is considered legitimate, the F.B.I. will at times simply take over the case itself and work it with the N.S.A.
The livelihood of skyscrapers is hardly linked to national security it's indicative of economic growth.
They endangered US economic security, "which in turn is directly linked to our national security".
Mr. Bush, linked to his national security staff by teleconference from Camp David, asked for one last review of the details on Saturday morning before he ordered the dispatch of B-2 bombers from Missouri to their Afghan targets.
