WhatsApp is probably the most widely-used instant messaging service for phones and tablets. It also is the most secure of all the popular instant messaging products although perhaps not quite as secure as some of the lesser-known products.
This level of security wasn’t always available in WhatsApp. The service was hacked many times in its first few years. Last year, WhatsApp’s new owners Facebook decided enough was enough. As a result, they announced a new partnership with Open Whisper Systems in a deal that would finally bring end-to-end encryption to the service. Experts were quickly impressed, as Wired claimed the solution was “practically uncrackable“, and the Wall Street Journal stated that “the encryption is so robust that even the law enforcement won’t be able to decrypt WhatsApp messages.“
Instead of storing the keys for unscrambling the encryption on a centralised server that’s owned and operated by the WhatsApp developers, end-to-end encryption works by instead only storing the keys on a user’s device. When combined with TextSecure, which uses a protocol called “forward secrecy” to issue a fresh key for every new message. This system is radically different from other instant messaging services that re-use encryption keys over and over.
Storing the keys only on a user’s device also means there is no “back door” to the system. Even the folks at WhatsApp cannot read your messages and, of course, they cannot supply copies of those messages to government agencies, even if a court order demands copies.
Nothing is ever perfect. A clever hacker or a government employee may find a method to crack any encryption scheme. Once that is done, the crypto experts probably will create a new method of securing communications that will lock out the latest cracking method. In the meantime, WhatsApp remains the most secure of all the popular instant messaging service for phones and tablets.
WhatsApp for iPhone, Android, BlackBerry, Nokia S40, Nokia Symbian, and Windows Phone may be found at http://www.whatsapp.com.