WhatsApp adds a highly requested feature: Messaging from multiple devices

Of course, there are some new security features at play here, many of which work entirely behind the scenes. Unlike the old days of using WhatsApp on the Web, for instance, the devices you connect to your account will get their own set of unique encryption keys. Even if a hacker manages to compromise one device’s set of keys, they can’t be used to decrypt messages sent to someone else — or to another one of your devices — because WhatsApp encrypts each outgoing message specifically for each gadget. (If you’re in the mood for even more technical rigor, the company has a white paper outlining all the juicy details.)