Vintage US security posters range from bizarre to terrifying

Early motivational posters hammered home employees’ solemn duty of secrecy

The earliest posters often put religion front and centre, emphasising America’s Christian faith in contrast to “godless” Communist states

Agents were reminded that foreign travel was full of potential security pitfalls

As the Swinging Sixties got underway, the NSA attempted to harness the “groovy” vibe in the name of national security

A valiant but tenuous attempt to link Flower Power romance to security clearance levels

The growing popularity of mind-alternating substances was felt to be worth a psychedelic anti-drugs warning

Even more ill-advised was the agency’s attempt to cash in on disco fever in the 1970s

Culminating in this shameless appropriation of John Travolta in Saturday Night Fever

But, despite the changing times, the core message remained: the NSA’s secrecy was paramount

The posters could get extremely specific, as with this flyer warning against car-pool gossip

Leaving coffee cups and spare change in filing cabinets was apparently also a problem

But the overall message was clear - take your eye off the ball, and prepare for pestilence, famine, war and death