A few weeks after WhatsApp did it, Viber has updated its messaging app to support end-to-end encryption and will be rolling out the feature in the following weeks. While Viber is not widely used in the US, it is pretty big in eastern Europe.
While it is interesting to see how end-to-end encryption was a niche feature for ages and suddenly it becomes a hot topic. The Snowden revelations and the following security fallout had an influence for sure, but the growing role of messaging system in online shopping is also relevant, I think.
What I find even more interesting is how key distribution was turned on its head: previous generations of instant messaging system treated all clients as equals and deploying end-to-end encryption meant distributing the private keys to all of them. Both WhatsApp and Viber treat the mobile phone as the primary device: it owns the identifier (the phone number) and authenticates secondary devices by scanning the QR code they display.
Keeping the keys on a mobile phone makes sense, most people have one, it is generally owned by the user and carried by her and its storage is often encrypted. A desktop computer is often shared, or owned by a corporation, and full disk encryption is pretty rare.
In a decade the desktop computer went from the center of the digital hub to being a secondary terminal…