Source: http://9to5google.com/2015/05/12/google-...

Following a Reddit AMA on government surveillance, Google has admitted that while it does encrypt Hangouts conversations, it does not use end-to-end encryption, meaning the company itself can tap into those sessions when it receives a government court order requiring it to do so. This contrasts with the end-to-end encryption used by some services, like Apple’s FaceTime, which cannot be tapped even by the company offering the service.

Motherboard noted that Google has always been vague about the level of encryption offered for Google Hangouts, and that when pressed by principal technologist at the American Civil Liberties Union Christopher Soghoian, the company would say only that messages were encrypted “in transit” …