Japanese messaging app Line has become the latest large platform to enable end-to-end encryption for its users, frustrating governments and other would-be eavesdroppers.

The feature allows users of the Line apps on smartphones and desktops to send messages that are fully encrypted on a device level. Similar to the encryption employed by Facebook’s WhatsApp and Apple’s iMessage, Line’s implementation of the protocol leaves the company itself unable to decrypt and read user messages, even under legal duress.

Line, which has called the feature “Letter Sealing”, says that it will initially be applied by default on Android for users with only one smartphone enabled, and that users on other platforms can manually turn it on.

End-to-end encryption has frustrated the authorities in multiple countries, where it leaves law enforcement unable to compel messaging providers to turn over the contents of suspects’ messages. In the US, Apple was forced to reject a court order from the Justice Department earlier this year, when the federal government attempted to read chats between two suspected drug dealers.

Line corporation launched its messaging app in 2011, and currently boasts more than 600 million users worldwide. The majority of those are in east and southeast Asia, but the company also boasts strong penetration in India, Spain and Chile.