A recent update for WhatsApp on Android has introduced end-to-end encryption. Unlike similar communications on other major networks from Facebook and Google, WhatsApp is unable to decrypt user messages, even if they were forced to for legal reasons. Many suggest it is the strongest encryption available on any major text service.
WhatsApp teamed up with Open Whisper Systems to create the new feature. Open Whisper was previously responsible for a number of apps but it was its TextSecure program that caught the company’s attention.
It uses forward secrecy to keep messages encrypted even if the key is compromised in the future. TextSecure is thought of quite highly among the security community after being published and withstanding several public audits.
It took the company around 6 months or more to ready TextSecure for WhatsApp's massive user base. There’s no information on when the feature may come available on iOS, but Open Whisper will continue its work both in-house and on other major collaborative efforts like this one in the mean time.
As some have suggested its a pretty strong move forward for end-to-end encryption on user messages, considering the more than 600 million users on the WhatsApp network, this is the largest deployment of this kind of encryption.