End-to-End Encryption Comes to Skype Through Signal Partnership

Microsoft is testing a new "Private Conversations" feature in Skype, which is being introduced through a partnership with Signal.Skype is using the Signal Protocol for the feature, allowing users to take advantage of strong end-to-end encryption for more secure communications.
Private Conversations are available for one-on-one conversations on Skype, with users able to initiate a private conversation by tapping on the "+" icon and then selecting "New Private Conversation." Once a conversation is