In the latest video about North Korea from Lankov, I heard something interesting: a device owner cannot open someone else’s file, whether on a computer or on a phone, unless it is signed with a special digital signature from the government. Intrigued, I researched the details for myself and for you.
On their phones, they use a modified old “KitKat” Android (2013), and on computers—a modified Fedora Linux, Red Star OS 3, with a shell that mimics the macOS interface from Apple (the previous one mimicked Windows XP). It is said that this design choice may have been influenced by the fact that leader Kim Jong Un was seen with an iMac on his desk, and apparently, he said make it the same.
North Korean smartphones are equipped with hidden surveillance features that automatically take screenshots every five minutes, storing them in a secret folder accessible only to authorities, not the user. According to other sources, screenshots are taken when applications start, apparently pseudo-randomly. There is also censorship: if you type “South Korea” (남조선) in any app, the system automatically replaces it with “puppet state” (괴뢰국가). One hundred percent of the phones are obviously Chinese, modified by China for Korea. By the way, the collected screenshots are accessible to users, but they cannot be deleted. This application, Trace Viewer, is clearly created to remind users: everything that they do on the tablet or phone can be known to the government.
All media content in Red Star OS, including documents, images, audio and video files, is automatically marked with a watermark containing a unique serial number of the hard drive, which allows authorities to track its origin and distribution. That is, you cannot take a photo and send it to someone, because it will either just not open on that phone, or, apparently, in rare cases, if sharing is allowed, in the new place there will be traces of both who is the author of the photo and who is the next owner. But this is underdeveloped, and direct file sharing is still limited. You can only use it yourself. Of course, nothing can be deleted from the phone without a trace. It is not allowed to have more than one device per person (seems to apply separately to a tablet and a phone).
North Korean mobile devices use a strict system of digital signatures (NATISIGN for government-approved content and SELFSIGN for content created on the device), which means that any file without these signatures cannot be opened at all. The system of signatures and signature verification is at the level of the operating system, not applications. This applies to all files that people create, both on phones and on computers. I see a huge number of edge cases here, but there is little information and no one to ask.
The penalties for accessing unauthorized foreign media, such as K-pop or South Korean dramas, are extremely harsh. If an “undesirable file” is found on a CD inserted into a computer with Red Star OS, the system will eject the CD, record the path to the file, display a graphical warning, take screenshots, and then forcefully reboot the system after 1000 seconds.
North Korea manages a national intranet network called Kwangmyong, “walled garden,” which is completely isolated from the global internet and is available to most citizens only for government-approved websites and email systems.
When you first launch the browser Naenara (based on Firefox 3.5), the default homepage is the IP address “10.76.1.11.” That is, their internet is essentially an intranet.

