WASHINGTON: Facebook announced Friday it would roll out optional "end to end encryption" for its Messenger application, following a trend aimed at stronger security and protection against snooping. The US technology giant said this feature would be known as "secret conversations" which can be read only by the sender and recipient. "Providing more ways for people to safely share is an important part of making the world more open and connected," the social network's vice president David Marcus said on his Facebook page. "Whether you're asking a doctor for medical advice, sending sensitive account information to your spouse, or even your Social Security number, it's important to have options available for sharing these kinds of very sensitive messages." Facebook earlier this year began implementing this end-to-end encryption on its WhatsApp messaging service, and Google, Apple and others have been making similar moves.