Facebook is taking a big step toward keeping Messenger users'
conversations safe from prying eyes: The company is testing a new
feature it calls "secret conversations," which uses end-to-end
encryption to lock up messages.
Using end-to-end encryption means that
only the sender and recipient of a message will able to unlock and read
it - even Facebook itself won't be able to see what you're talking
about. In a blog post Friday announcing the test, Facebook highlighted
sensitive topics like health and financial information as among the
reasons users might want to use it.
End-to-end encryption has seen
a boom in popularity in recent years as mainstream tech companies have
started integrating it into their products amid heightened cyber-security
and surveillance fears. But that boom has also raised concerns from
some law enforcement officials that it could stop them from being able
to access the communications of criminals and terrorists even when
investigators obtain a warrant.
The Messenger feature will not be
turned on by default; users will have to choose to start a secret
conversation. In addition to providing end-to-end protections, the
feature will also allow users to set a time limit for how long each
message will remain visible in a conversation. However, secret
conversations currently don't support some popular features, like
sharing GIFs or videos.

Only a limited number of Messenger users
will be able to try out the feature for now, but Facebook says it plans
to make it more widely available later this summer.
Messenger's
secret conversations rely on technology from Open Whisper Systems, which
also makes the free end-to-end encrypted messaging and voice call app
Signal. Facebook used the same technology to build end-to-end encryption
into WhatsApp, which it owns, in a process completed earlier this year.
The company is following in the footsteps of Apple, whose iMessage
system has protected users' conversations with end-to-end encryption
since 2011.
Matthew Green, a Johns Hopkins University computer
science professor who consulted with Facebook on their plans to deploy
end-to-end encryption in Messenger, says he's increasingly seeing a sort
of sea change in how developers view the technology.
"It's becoming a minimal requirement for deploying an app like this," Green said.
But
having a major player in the instant messaging world such as Facebook
dive into this space also extends the privacy protection to an audience
that otherwise might not use it, according to Green. "There are people
who aren't going to download some special app, so the fact it is being
built into the things they already use is a really big deal," Green
said.
© 2016 The Washington Post