North Korea has heavy state censors and few citizens have internet access
Details of a home-grown computer operating system developed by North Korea have emerged.
Information about Red Star, as it is known, was made public by a Russian blogger studying in North Korea, who bought the program off the street.
Further analysis by a government institute in neighbouring South Korea said the operating system is aimed at monitoring user activity.
However, very few North Koreans own a computer or have internet access.
Web content is also heavily censored.
It is designed "to control [North Korea's] own information security", a report by South Korea's Science and Technology Policy Institute (STPI) said.
"Due to few applicable programmes available, Red Star will not even be easily distributed in North Korea," it added.
The Russian blogger, identified only as Mikhail, said Red Star could be bought in Pyongyang for around $5. He has also posted a series of screenshots on his blog.
The operating system represents the determination of North Korea to advance its own computer technology, based on its "Juche" self-reliance philosophy.
The Red Star operating system uses a popular Korean folk song as its start-up music and numbers years using a calendar which starts counting from the birth of state founder Kim Il-sung, making 2010 the 99th year.
It is Linux-based but is heavily influenced by Microsoft with open-source versions of the software giant's Office programmes, including several familiar games.
It runs only in the Korean language and takes 15 minutes to install, reports said.
It has games, an e-mail system known as Pigeon and a Mozilla's Firefox internet browser - which has the North Korean government website as a home page.
The US government has banned the uploading and downloading of open source code to residents of a handful of countries on its sanctions list, which includes North Korea.
The STPI report also said that North Korea has launched a cyber-war unit that targets sites in South Korea and the US.
In July last year South Korea experienced a wave of cyber-attacks which attempted to paralyse a number of websites. US websites including the Pentagon and the White House were also targeted.
Reports suggested that the attacks might have originated in North Korea.