The beauty of the Linux operating system is that anyone can use it, customizing it to suit their purpose. 
 
 And, for North Korea, that purpose is creating an operating system that can be used to spy on the citizenry. 
 
 “We found that the features implemented in Red Star OS are the wet dream of a surveillance state dictator,” said Florian Grunow and Niklaus Schiess, two researchers who presented their assessment Sunday of a leaked version of Red Star OS 3, the North Korean Linux distribution. “It provides a set of surveillance features like the capabilities to watermark different types of files that can be used to track the distribution of documents and multimedia files.” 
 
 Grunow and Schiess said that the latest version of Red Star has the guts of Linux and the looks of Mac OS mixed in with its spy-on-the-populace features. 
 
 The presentation follows up on the initial impressions that Grunow published earlier this year. 
 
 North Korea, known for its secrecy, doesn’t get much press when it comes to technology, though it made headlines earlier this year when it was fingered as the likely culprit behind the hacking of Sony Pictures. ||||| The goal of a totalitarian regime is to control everything in a country: information, resources, and power. In the 21st century, that even includes omnipotence over the code that the country's computers use. 
 
 Enter RedStar OS: North Korea's own Linux based operating system, designed to monitor its users and remain resilient to any attempts to modify or otherwise exert control over it. On Sunday at Chaos Communication Congress, a security, art, and politics conference held annually in Hamburg, Germany, researchers Niklaus Schiess and Florian Grunow presented their in-depth investigation of the third version of the operating system. 
 
 Schiess and Grunow wanted to document the inner workings of RedStar because its use of freely available software, and in particular Linux, goes against the principles of the open source movement. 
 
 “They are using something that is supposed to support free-speech,” Grunow said. 
 
 As for what it actually looks like, “it's a fully featured desktop system,” Schiess told Motherboard. Under the hood, RedStar is based on Fedora 11, an iteration of the popular Linux distribution which was released in 2009, and works with a kernel—basically the heart of an operating system—from 2011. It comes with everything a user might need, including word processing and music creation software, and a modified Firefox browser. These applications, the desktop environment, and the underlying structure of the file system attempts to mimic that of Mac OSX. 
 
 But that is where the similarities with other operating systems end, and RedStar's totalitarian bent begins. RedStar enforces its dominance by rigorously monitoring any changes that a user might make, reacting accordingly, as well as creating “watermarks” on the files on any USB stick inserted into it. 
 
 In short, whenever a USB storage device containing documents, photos or videos is inserted into a RedStar computer, the operating system takes the current hard-disk's serial number, encrypts that number, and then writes that encrypted serial into the file, marking it. 
 
 The purpose “is to track who actually has this file, who created this file, and who opened this file,” Schiess said. That watermarking feature has been reported previously by the researchers, and others have published analyses of RedStar after versions of it have leaked or found their way out of the country. But Schiess and Grunow's newly presented dive into RedStar goes further, and is the most comprehensive picture of the OS yet. 
 
 RedStar “is highly customized,” Schiess said. “They've also added a lot of features to improve the security of the system.” 
 
 Those include a pre-installed firewall, extra protections of some of the system's core files, and a small program which constantly crawls the computer to check for any changes made to those files. 
 
 This program calls up a list of MD5 hashes—basically cryptographic fingerprints of files—and “as soon as this daemon sees that one of these files has been changed, it immediately reboots the system,” Schiess said. However, depending on the circumstances, the computer can sometimes get locked into an infinite cycle of booting and rebooting. 
 
 RedStar also even has its own anti-virus system, complete with a graphical user interface, which gets its updates from a server, unsurprisingly, located in North Korea. 
 
 All of these changes likely aren't designed to protect the system from an outside attacker, say a foreign nation attempting to remotely hack into North Korea's computer systems, but from RedStar's own users, the researchers said. 
 
 Indeed, it's clear that RedStar was not designed to be used outside the country, because the operating system's internet browser points to internal, North Korean IP addresses, as does the anti-virus update server, which can't be accessed from the outside world. (There is also a server version of RedStar however, that is used to run two public facing, North Korean websites). The applications are likely made by ten different developers: the researchers found the internal email addresses of different coders within the operating system's changelog. 
 
 The insular nature of the operating system, and the country, is further reflected in RedStar's custom crypto, which takes established encryption algorithms such as AES, and puts a new twist on them. It's unclear whether this was done because RedStar's developers feared these forms of encryption had been backdoored, meaning that an adversary could take advantage of them and access sensitive data, or whether they thought they could make some genuine improvements to the cryptography being used. 
 
 Regardless, “It shows they didn't even want to rely on foreign crypto,” Grunow said. 
 
 “They completely control every aspect of this system,” Grunow said. ||||| SINGAPORE/SEOUL (Reuters) - North Korea’s homegrown computer operating system mirrors its political one, according to two German researchers who have delved into the code: a go-it-alone approach, a high degree of paranoia and invasive snooping on users. 
 
 A North Korean operating system is seen in this screen shot taken in Seoul December 23, 2015. REUTERS/James Pearson 
 
 Their research, the deepest yet into the secretive state’s Red Star OS, illustrates the challenges Pyongyang faces in trying to embrace the benefits of computing and the internet while keeping a tight grip on ideas and culture. 
 
 The researchers, Florian Grunow and Niklaus Schiess of German IT security company ERNW GmbH, spoke to Reuters before presenting their findings to the Chaos Communication Congress in Hamburg on Sunday, a gathering of hackers and security researchers. 
 
 The operating system is not just the pale copy of western ones that many have assumed, they concluded after downloading the software from a website outside North Korea and exploring the code in detail, 
 
 “(Late leader) Kim Jong Il said North Korea should develop a system of their own,” said Grunow. “This is what they’ve done.” 
 
 North Korea, whose rudimentary intranet system does not connect to the outside internet but allows access to state media and some officially approved websites, has been developing its own operating system for more than a decade. 
 
 This latest version, written around 2013, is based on a version of Linux called Fedora and has eschewed the previous version’s Windows XP feel for Apple’s OSX — perhaps a nod to leader Kim Jong Un, who like his father has been photographed near Macs. 
 
 But under the hood there’s a lot that’s unique, including its own version of encrypting files. “This is a full blown operation system where they control most of the code,” said Grunow. 
 
 This, the researchers say, suggests North Korea wants to avoid any code that might be compromised by intelligence agencies. 
 
 “Maybe this is a bit fear-driven,” said Grunow. “They may want to be independent of other operating systems because they fear back doors” which might allow others to spy on them. 
 
 Grunow and Schiess said they had no way of knowing how many computers were running the software. 
 
 While private computer use is on the rise in North Korea, visitors to the country say most computers still use Windows XP, now nearly 15 years old. 
 
 NO TAMPERING 
 
 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 addresses a more pressing concern: cracking down on the growing underground exchange of foreign movies, music and writing. 
 
 Illegal media is usually passed from person-to-person in North Korea using USB sticks and microSD cards, making it hard for the government to track where they come from. 
 
 Red Star tackles this by tagging, or watermarking, every document or media file on a computer or on any USB stick connected to it. That means that any file could be traced back to anyone who had previously opened or created the file. 
 
 “It’s definitely privacy invading, it’s not transparent to the user,” said Grunow. “It’s done stealthily, and touches files you haven’t even opened.” 
 
 Such efforts, says Nat Kretchun, an authority on the spread of foreign media in the isolated country, reflect North Korea’s realisation that it needs “new ways to update their surveillance and security procedures to respond to new types of technology and new sources of information.” 
 
 There’s no sign in the operating system, the researchers say, of the kinds of cyber attack capability North Korea has been accused of. 
 
 “It really looks like they’ve just tried to build an operating system for them, and give the user a basic set of applications,” says Grunow. That includes a Korean word processor, a calendar and an app for composing and transcribing music. 
 
 North Korea is not the only country to try to develop its own operating system. Cuba has its National Nova, while China, Russia and others have tried to build theirs.
– Check out North Korea's computer operating system, and it feels almost like you're using a Mac. Red Star OS is a "fully featured desktop system," German researcher Niklaus Schiess tells Motherboard, complete with word processing software and a revamped Firefox browser. But like almost everything else in the totalitarian nation, something more nefarious lies underneath, per Schiess and Florian Grunow, who both scrutinized a version of the Linux-based OS that was leaked in 2014. They presented their findings Sunday to the Chaos Communication Congress—what Reuters calls "a gathering of hackers and security researchers"—in Hamburg, Germany. "We found that the features implemented in Red Star OS are the wet dream of a surveillance state dictator," the two say, describing a "fear-driven" OS that features "malicious functionality." Among the features of the OS are custom-developed encryption and the watermarking of documents and multimedia files so they can be tracked as they're transferred from computer to computer via USB sticks, Reuters notes. "It's definitely privacy invading, it's not transparent to the user," Grunow says, per the news agency. It "touches files you haven't even opened." There's also a built-in firewall, anti-virus scanner, and a program that reboots the OS or displays an error message if anyone tries to mess with the OS, per Motherboard. What made the OS particularly interesting to Grunow and Schiess is the fact that the nation is using the open source Linux OS, which can be customized for a user's particular purposes—in North Korea's case, snooping on its own, per Re/code. "North Korea abuses the principals of free software to provide an operating system that suppresses free speech," the researchers note in their CCC abstract.