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Wired reports Facebook has launched "Secret Conversations," a beta feature that a small number of users are now testing that encrypts messages end-to-end, so know one can read the communications except for the sender and receiver. All of Facebook's 900 million users will be able to opt-in to encrypted messages later this summer. Facebook and its WhatsApp will both be encrypted, the largest services on the internet providing secure communication. Viber added encryption for its 700 million users, and Google announced in May that its messaging app Allo would also offer opt-in end-to-end encryption. Facebook is using Signal, which was created by the non-profit Open Whisper Systems, and is also available as an app on its own. “This... brings access to encrypted messaging to nearly a billion more people,” says Matt Green, a Johns Hopkins computer scientist. “If you make a list of all the messaging services that have end-to-end encryption and the ones that don’t, we’re starting to live in a world where the ones that don’t are mostly in China.”