North Korea is spying on its citizens' mobile phones - by James Pearso

Kim Jungs Family Tree

Isolated North Korea is developing sophisticated tools to digitally spy on its citizens, who are increasingly using mobile devices to connect to each other, a US government-funded report released on Wednesday says.

The report, "Compromising Connectivity", says North Korea has allowed the growing use of mobile phones and domestic internet access in return for the detailed information the network feeds Pyongyang's surveillance state.

"By giving citizens new networked technologies like mobile phones and tablets, the government is able to automatically censor unsanctioned content and observe everything citizens are doing on their devices remotely," Nat Kretchun, the report's lead author, told Reuters.

"The authorities have found ingenious ways to turn those new technologies against the North Korean people who are adopting them," said Kretchun, a researcher at InterMedia, the Washington-based organization that produced the report.

North Korea's strategies for keeping tabs on its citizens have been in the limelight since last month's dramatic killing of leader Kim Jong Un's estranged half-brother at an airport in the Malaysian capital.

Access to outside information is tightly controlled in North Korea. South Korean television shows and Hollywood films are often shared in a genuinely social network of people trading or swapping files via Bluetooth, or small and easily-concealed USB sticks.

To fight such use, North Korea has rolled out mandatory software updates to mobile devices on its network that actively seek out and delete illegal foreign media files, the report says.

On North Korea's own "Red Star" computer operating system, software scans text documents for specific words or phrases deemed unfavorable by the regime and deletes them.

Read more: North Korea is spying on its citizens' mobile phones-Reuters