WhatsApp starts encrypting users' messages
WhatsApp has turned on an encryption system to protect messages sent with the Android version of its app.
The WhatsApp Android application has been downloaded about 500 million times.
It said the data scrambling system should make it much harder to eavesdrop on the messages users exchange.
Tech firms have faced criticism by law enforcement figures who said greater use of encryption made it harder to track criminals and extremists.
Data scramble
The encryption system being applied to WhatsApp is called TextSecure and has been developed by a non-profit group called Open Whisper Systems.
"I do think this is the largest deployment of end-to-end encryption ever," said TextSecure developer Moxie Marlinspike in an interview with tech news site Wired.
Unlike other encryption systems, which often scramble messages only as they travel from a device to the servers that companies use to route them to their recipients, TextSecure keeps the encryption intact throughout a message's journey from handset to handset.
Initially the encryption is being applied only to messages sent via the Android version of WhatsApp. Soon it will be extended to group messages, photos and videos sent via the Android app.
Open Whisper said it also planned to develop versions of TextSecure that work with WhatsApp apps on other smartphone operating systems but did not give a date for when those would be ready.