Microsoft teams up with Signal for new end-to-end encryption

Microsoft has teamed up with encrypted communications app Signal on a new end-to-end encrypted messaging feature called Private Conversations.

Microsoft said in a short blog post that Private Conversations are now in preview for Skype Insiders.

Skype users will now be able to have end-to-end encrypted Skype audio calls and text conversations, including the ability to upload multimedia files, using the Signal Protocol developed by Open Whisper Systems.

To start a Private Conversation, Skype users need to tap the + icon, select New Private Conversation, and choose a contact. Skype then sends the user an invite with seven days validity. Once accepted, the Private Conversation starts like any other Skype call or message.

Once one ends or deletes a Private Conversation, one needs to send a fresh invite to start another and recover the chat history. Private Conversations are also specific to a device (the feature is supported on iOS, Android, Linux, Mac, and Windows Desktop), so if users switch to another device they will need to re-send the invite.

Microsoft further clarified that users cannot edit a message or forward files within a Private Conversation. Only emoticons, files, and audio messages can be sent. Privacy of the Skype chat is indicated by a lock icon next to the contact's name, which can be seen on the right.

"With Private Conversations, you can have end-to-end encrypted Skype audio calls and send text messages or files like images, audio, or videos, using the industry standard Signal Protocol by Open Whisper Systems," said Microsoft program manager Ellen Kilbourne yesterday.

"The content of these conversations will be hidden in the chat list as well as in notifications to keep the information you share private. 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."