"Snapchat, Skype put users' "human rights at risk," Amnesty Int'l reports", 24 Oct 2016

...Microsoft’s Skype also fared poorly, receiving 40 out of 100. Skype uses encryption, but not end-to-end encryption for its instant messaging, according to Amnesty.

Microsoft defended its security protocols with Skype in a statement to CBS News. 

“We agree with Amnesty International about the importance of encryption,” a Microsoft spokesperson said. “At the same time, this report does not accurately reflect Skype’s comprehensive work to protect people’s privacy and security. Skype uses encryption and a range of other technical security measures, and we protect people’s privacy through legal challenges, advocacy, and strong policies to notify customers when we receive government requests for their data or detect attempted third party intrusions.”...