Microsoft Corp. is bringing end-to-end encryption to Skype through a newly announced partnership with Open Whisper Systems, the folks behind the open-source encrypted communications application Signal.

The new service, called Skype Private Conversations, will allow users to encrypt audio calls and text messages along with any images, audio or video files sent via Skype’s text messaging feature.

The system has some limitations, albeit for privacy reasons. According to Microsoft, preview messages from Private Conversations will not show in chats or notifications, users cannot edit a message and Private Conversations themselves are tied to a specific device, requiring a new invitation to be sent and accept to be accessed on another device. Initially the feature will not support video calls either.

“The content of these conversations will be hidden in the chat list as well as in notifications to keep the information you share private,” Microsoft Program Manager Ellen Kilbourne said in a blog post. ‘You can only participate in a private conversation from a single device at a time. You can switch the conversation to any of your devices, but the messages you send and receive will be tied to the device you’re using at the time.”

Skype isn’t the first messaging platform to use the Signal open-source protocol and it won’t be the last. Facebook Inc. has long been a fan, using Signal to provide encrypted messaging in both Messenger and WhatsApp, the former gaining the option in September 2015. Other services that use the protocol include Google LLC’s Allo and Apple Inc.’s iMessage.

End-to-end messaging will not be immediately available to all Skype users, but for those who want to get their hands on it, it’s initially available for Windows, Mac, Linux, Android, or iOS via the Skype Insider program.

Image: Signal