For a comparison to play out, we must first look at the roots of both the companies to better understand the situation. While WhatsApp is owned by a big tech corporation, Signal Messenger LLC works under the non-profit Signal Foundation. WhatsApp and Signal share a history with Brian Acton, the ex-co founder of WhatsApp, leaving his invention behind post-Facebook acquisition to join the Signal Foundation. The risk of user privacy was one of his reasons for quitting the platform. If both WhatsApp and Signal use the end-to-end encryption protocol developed by Open Whisper Systems, why is it that one app is said to be more secure than the other?
End-to-end encryption means that even the messenger cannot see the chats. However, what users seem to forget is that the backed-up messages that ultimately go to the cloud or even the metadata used to carry communication between two endpoints are not encrypted. The major loophole in WhatsApp's security model is that even though the messages cannot be read by their authorities, technicalities like the what, who, when of the messages can still be derived.
On the other hand, Signal doesn't send unsecured backups to the cloud. Instead, your messages get stored with a 4-digit passphrase in an encrypted database on your phone that only you can see. In fact, Signal takes it one step further by introducing Sealed Sender, with which no one, not even Signal, can know who is messaging whom. With Signal, your metadata is encrypted too.
When you log into a messenger, you are obliged to provide some or most of your information to them. Or are you? Let's take a look at some of the data that the messenger apps collect from their users.
Payment Info, among many others
Phone Number (only for registration)
Did you know that your keyboard can learn what you've typed and transfer the information depending on which app you're using? Forget WhatsApp, many mainstream apps are at the receiving end of the blame. For this, Signal has introduced the Incognito Keyboard feature so that no other app in your window can see what you're typing. Signal is currently trending the top charts as seen in their recent tweet. Why Signal over WhatsApp? What do you think is better?