Growing up in Soviet Ukraine in the
1980s, Whatsapp founder Jan Koum
learned to distrust the government
and detest its surveillance. After he
emigrated to the U.S. and created his
ultra-popular messaging system
decades later, he vowed that Whatsapp
would never make eavesdropping easy
for anyone. Now, Whatsapp is
following through on that anti-
snooping promise at an
unprecedented scale.
On Tuesday, Whatsapp announced
that it's implementing end-to-end
encryption, an upgrade to its privacy
protections that makes it nearly
impossible for anyone to read users'
messages—even the company itself.
Whatsapp will integrate the open-
source software Textsecure, created by
privacy-focused non-profit Open
Whisper Systems, which scrambles
messages with a cryptographic key
that only the user can access and
never leaves his or her device. The
result is practically uncrackable
encryption for hundreds of millions of
phones and tablets that have Whatsapp
installed—by some measures the world's
largest-ever implementation of this
standard of encryption in a messaging
service.
"Whatsapp is integrating Textsecure
into the most popular messaging app
in the world, where people exchange
billions of messages a day," says
Moxie Marlinspike, Open Whisper
System's creator and a well known
software developer in the
cryptography community. "I do think
this is the largest deployment of end-
to-end encryption ever."
Textsecure has actually already been
quietly encrypting Whatsapp messages
between Android devices for a week.
The new encryption scheme means
Whatsapp messages will now travel all
the way to the recipients' device
before being decrypted, rather than
merely being encrypted between the
user's device and Whatsapp's server.
The change is nearly invisible, though
Marlinspike says Whatsapp will soon
add a feature to allow users to verify
each others' identities based on their
cryptographic key, a defense against
man-in-the-middle attacks that
intercept conversations. "Ordinary
users won't know the difference," says
Marlinspike. "It's totally frictionless."
In its initial phase, though,
Whatsapp's messaging encryption is
limited to Android, and doesn't yet
apply to group messages, photos or
video messages. Marlinspike says that
Whatsapp plans to expand its
Textsecure rollout into those other
features and other platforms,
including Apple's iOS, soon. He
wouldn't specify an exact time frame,
and Whatsapp staffers declined to
comment on the new encryption
features. Marlinspike says the
Textsecure implementation has been
in the works for six months, since
shortly after Whatsapp was acquired
by Facebook last February.
Whatsapp's Android users alone
represent a massive new user base for
end-to-end encrypted messaging:
Whatsapp's page in the Google Play
store lists more than 500 million
downloads. Textsecure had previously
been installed on only around 10
million gadgets running the Cyanogen
mod variant of Android and about
500,000 other devices.
The only encrypted messaging system
that compares in size is Apple's
iMessage, which also claims to use a
version of end-to-end encryption.
Compared with Textsecure, however,
Apple's iMessage security has some
serious shortcomings. iMessage
doesn't track which devices'
cryptographic keys are associated with
a certain user, so Apple could simply
create a new key the user wasn't
aware of to start intercepting his or
her messages. Additionally, many
users unwittingly back up their stored
iMessages to Apple's iCloud, which
renders any end-to-end encryption
moot. Plus, unlike Textsecure,
iMessage doesn't use a feature called
"forward secrecy" that creates a new
encryption key for each message sent.
This means that anyone who collects a
user's encrypted messages and
successfully cracks a user's key can
decrypt all their communications, not
just the one message that uses that
key.
Whatsapp's rollout of strong
encryption to hundreds of millions of
users may be an unpopular move
among governments around the world,
whose surveillance it could make far
more difficult. Whatsapp's user base
is highly international, with large
populations of users in Europe and
India. But Whatsapp founder Jan
Koum has been vocal about his
opposition to cooperating with
government snooping. "I grew up in a
society where everything you did was
eavesdropped on, recorded, snitched
on," he told Wired UK earlier this
year. "Nobody should have the right to
eavesdrop, or you become a
totalitarian state—the kind of state I
escaped as a kid to come to this
country where you have democracy
and freedom of speech. Our goal is to
protect it."
