We already know that the US National Security Agency (NSA) has been spying on virtually every computer connected to the internet - to say nothing of apparently similar efforts by our own authorities.

What we didn't know was that NSA agencies were able to hack computers that weren't even connected to the web.

According to documents leaked by Edward Snowden and reported by the New York Times, the NSA was able to put software on around 100,000 computers around the world to carry out surveillance and prepare the ground for cyberattacks.

But the report also said that the agency had been able to gain entry to devices that were not otherwise online, thanks to the use of relatively simple, but secret technology.

The paper said that tiny circuit boards and USB cards were placed in computers by agents as early as 2008, and then transmitted data via radio waves picked up by American forces.

In some cases the radio transmissions were able to be tracked by "briefcase-size relay stations" set up miles away from the computer, the Times reported. It said that these briefcase machines can hack data and send back messages to machines up to eight miles away.

"The radio frequency technology has helped solve one of the biggest problems facing American intelligence agencies for years: getting into computers that adversaries, and some American partners, have tried to make impervious to spying or cyberattack," the NYT said.

"In most cases, the radio frequency hardware must be physically inserted by a spy, a manufacturer or an unwitting user."

The program, known as Quantum, targeted systems in the Chinese military, as well as Europe, Russia, Mexico, Saudi Arabia and Pakistan among others. But the Times said there was no evidence the NSA had used the radio tech outside of the US.

Loading Slideshow...
  • Fingerprint Gel

    The Japanese government counter-terrorism practice of <a href="http://www.reuters.com/article/2007/11/20/us-japan-fingerprinting-idUST23858020071120" target="_hplink">fingerprinting foreigners who enter the country</a> may have inspired Doctor Tsutomu Matsumoto to invent "fingerprinting gels", a way of <a href="http://cryptome.org/gummy.htm" target="_hplink">faking fingerprints for scanners</a>. <a href="http://www.dansdata.com/uareu.htm" target="_hplink">Learn how</a> to make your own here.

  • White Noise Generator

    Worried someone around you is <a href="http://articles.businessinsider.com/2011-07-28/strategy/29998051_1_bank-employee-consent-conversation" target="_hplink">secretly recording everything you do?</a> No fear! There's a relatively low-tech way to defeat such snoops, via white-noise-producing <a href="http://www.amazon.com/Productive-Home-Security-Prducts-Jammer/dp/B002PJ7PYS" target="_hplink">audio jammers</a>. These tiny devices use white noise to blur the sound picked up by hidden microphones and other surreptitious recording devices.

  • LED-Lined Hat

    Hidden cameras got you down? Blind them all with a simple baseball cap lined with infrared LEDs. <a href="http://creator.wonderhowto.com/amiehold/" target="_hplink">Amie, a hacker on WonderHowTo</a>, shows the world <a href="http://mods-n-hacks.wonderhowto.com/how-to/make-infrared-mask-hide-your-face-from-cameras-201280/#" target="_hplink">how to make one</a>, while <a href="http://translate.google.com/translate?u=http%3A%2F%2Fwww.oberwelt.de%2Fprojects%2F2008%2FFilo%2520art.htm&langpair=de%7Cen&hl=en&ie=UTF8" target="_hplink">this German art exhibition</a> lays out how these ingenious devices work.

  • Bug Detector

    These receivers reveal the telltale electronic crackle of hidden mics and cameras. Strangely enough, they were around long before "surveillance culture" became a <a href="http://digitalcommons.law.yale.edu/ylsspps_papers/64/" target="_hplink">common phrase</a>. Today they're sold in all sorts of <a href="http://www.gadget-playground.com/bug-detection.html" target="_hplink">shops for surveillance paranoids</a>.

  • Camera Map

    Sometimes hiding your face isn't enough; sometimes you don't want to be seen at all. For those days, there's camera maps. The <a href="http://www.mediaeater.com/cameras/locations.html " target="_hplink">NYC Surveillance Camera Project</a> in the US is currently working to document the location of and working status of every security camera in New York City. <a href="http://bigbrotheriswatching.co.uk/Anpr_Camera_Locations.html" target="_blank">A similar project</a> is also in progress in the UK.

  • Dazzle Camouflage

    Credit to artist <a href="http://ahprojects.com/" target="_hplink">Adam Harvey</a> for this one. Inspired by the <a href="http://www.bobolinkbooks.com/Camoupedia/DazzleCamouflage.html" target="_hplink">"dazzle camouflage" </a>used on submarines and warships during World War I, he designed a series of face paint principles meant to fool the facial recognition schemas of security cameras. Check out <a href="http://dismagazine.com/dystopia/evolved-lifestyles/8115/anti-surveillance-how-to-hide-from-machines/ " target="_hplink">The Perilous Glamour of Life Under Surveillance</a> for some tips on designing your own camera-fooling face paint.

  • Throwaway Phones

    Disposable mobile phones <a href="http://www.amazon.co.uk/Pre-Pay-Mobile-Phones-Communication/s?ie=UTF8&page=1&rh=n%3A10394961" target="_blank">are more expensive than you think</a>, but they don't require personal information when you sign up.

  • RFID-Blocking Wallet

    Radio-Frequency Identification (RFID) chips are now <a href="http://electronics.howstuffworks.com/gadgets/high-tech-gadgets/rfid.htm" target="_hplink">regularly implanted</a> in passports, ID cards, credit cards and travel papers. These tiny chips make machine-reading your documents easier -- but could also let anyone with the right type of scanner <a href="http://articles.cnn.com/2006-07-10/tech/rfid_1_rfid-industry-rfid-journal-rfid-chips?_s=PM:TECH " target="_hplink">scrape your information <em>and</em> track your whereabouts</a>. Luckily, gadget geeks have come to the rescue again, this time with<a href="http://www.thinkgeek.com/product/8cdd/" target="_hplink"> RFID-blocking wallets</a>. These wallets create a Faraday cage around your items, keeping their data secure until you take them out to be scanned where they're supposed to be scanned. Destroying the chip is simpler: <a href="http://www.instructables.com/id/How-to-blockkill-RFID-chips/" target="_hplink">just nuke it in the microwave for five seconds</a>. Of course, whatever you're microwaving might <a href="http://www.youtube.com/watch?v=4_5UYcyO3Pg" target="_hplink">burst into flames</a> first...

  • Use Skype

    The progress of the government's so-called 'Snooper's Charter' is currently stalled in Parliament, but using Skype may be a way to avoid officials tracking your phone calls. <a href="http://www.techweekeurope.co.uk/comment/how-to-avoid-gchq-snooping-use-skype-71410">Tech Week Europe suggests that Skype users have less cause to be worried about their data</a> being intercepted. The reasons are pretty technical, and any system is fallible, but it may be worth looking into.