North Korea’s legal authorities have issued Ministry of State Security (MSS) employees with smartphones that encrypt voice calls, North Korean sources told Daily NK on October 16.

The encryption digitally scrambles voice data transmitted on the phone to prevent conversations from being understood if they are intercepted. When discussing confidential military-related matters, high-ranking officers in South Korea’s military are also required to use phones with voice encryption.

“Recently, all members of the MSS were given new smartphones that encrypt voice calls,” said a Pyongyang-based source on October 15. “The functionality of these phones is stronger than the previous Jindallae-type phones.”

A separate source in Pyongyang added, “There has been an increase in smartphone users, but people have always been worried about who is listening in on their calls. The security services cannot even trust the postal service [to send information], so they have focused on improving the security of the phones they use instead.”

MSS employees have been using the Jindallae 3 smartphone, which was released in June last year. The Jindallae is produced by Mangyongdae Information Technology Corporation, an IT company, and is considered a reasonable smartphone that is lighter and with more functions than the Arirang and Pyongyang-type phones. However, users have complained that the phone’s battery overheats and that malfunctions are common.

The popularity of the phone has declined due to these issues and ordinary consumers in North Korea are now buying the Arirang and the comparatively cheaper Pyongyang phones.

The new work phone supplied to MSS employees can be used to dial domestic numbers, but is limited to only receiving international calls. The encryption functionality on the phone is mandatory when users receive international calls or when making domestic calls.

According to the Korea Information Society Development Institute (KISDI), there were more than 3.7 million North Korean mobile phone users as of March 2018. Games, music and security apps are becoming increasingly popular on the phones.