In the wake of a major controversy over changes to user rules, WhatsApp is recommitting itself to full encryption and holding out the prospect of new features to protect user privacy.

These include the possibility of sending messages that can only be viewed once by the recipient. This could be useful, for example, if you need to send a password to family members, WhatsApp boss Will Cathcart says.

It will also be possible to set chats to disappear on their own after a certain time. People on the whole don't want their messages to stay forever, Cathcart argues, pointing out that we don't carry a recording device with us when we talk.