Researchers have dug into the source code of North Korea's homegrown computer operating system and confirmed Pyongyang's invasive snooping on users. Speaking to Reuters, Florian Grunow and Niklaus Schiess of German IT security company ERNW GmbH, said that the "Red Star" OS is not just a pale copy of western ones that many have assumed.

The latest version of the OS is based on a version of Fedora Linux and has eschewed the previous version's Windows XP feel for Apple's OSX.

Under the hood, there's a unique code, including a new version of encrypting files. This, the researchers say, suggests North Korea wants to avoid any back doors in the OS - code that might be compromised by intelligence agencies.

The Red Star operating system makes it very hard for anyone to tamper with it. If a user makes any changes to core functions - like trying to disable its antivirus checker or firewall - the computer will display an error message, or reboot itself.

Red Star also is alao cracking down on the underground exchange of foreign movies, music and writing.

It tackles this by tagging, or watermarking, every document or media file on a computer or on any USB stick connected to it.

Interestinlgy, the researchers found no sign in the operating system of the kinds of cyber attack capability North Korea has been accused of.

North Korea uses an intranet system does not connect to the outside internet but allows access to state media and some officially approved websites.