The Whatsapp Scandal
Since adding the feature in April, 2016, the Whatsapp app (or really its parent, Facebook) has paraded its "end to end encryption" as the reason to use it above all other smartphone message applications. It can handle calls, messages, video, files and just about everything any computer can and, because it's encrypted end to end, nobody can read, see or hear any of it unless you want them to.
The pitch has worked; over a billion people now use the app and it is particularly prominent among people who need encryption -- the computer protocol that makes reading your message impossible for anyone but the person you're sending it to.
Activists, particularly, use Whatsapp to communicate everything from places for emergency demonstrations to important announcements to the latest information about their personal lives. Whatsapp is, in effect, a universe of communications for a billion people. It does everything and everything it does is encrypted. With Whatsapp, they've been saying, you are safe from intrusion and spying.
The problem is, you're not safe at all; the encryption can easily be broken. That news, first made public in the Guardian, has provoked a public gasp and a joust between developers and activists covered by journalists who, anxious to provide both "sides", cloud the issue more than clarify.
Unlike many other debates, there aren't two sides to this story. Whatsapp is not safe because its encryption has a huge exploit (or weakness): a product of what the company says is an attempt to make life a lot simpler for its users. Basically, it rewrites the keys used for encryption without telling you and that means a third party (like the government) can decrypt what you've written.
This takes a bit of explanation. First, the basics...
Encryption uses keys -- long, random strings of numbers and symbols and letters that make no sense and cannot be guessed. You get two: a public key and a private key. When you send me an encrypted message, the encryption program garbles it beyond comprehension using my public key, which your email client downloaded (and saved) before sending me your first message.
When I get the email, I use my private key to decrypt it. If I don't have the private key, the email from you is unreadable: the garble the program turned it into. I apply my key and your message to me is magically transformed to human language. Unlike my public key that is all over the place, my private key is on my computer (or phone) and nowhere else.
That's the security and that's how the keys work in encryption.
Whatsapp works the same way except for one thing. When using an encryption program (like Signal) on my phone, when I change keys, I know the keys have been changed. When you change yours, I'll get a notification the moment I try to send you a new email because it detects the key change and sends the warning.