WhatsApp, the messaging service that Facebook acquired for $19 billion earlier in the year, has teamed up with Open Whisper Systems to offer end-to-end encryption on messages sent through the app.

WhatsApp's 600 million users will be receiving a boost in the security of their messages, as end-to-end encryption ensures that only the sender and receiver of the message will be able to access their conversation and all the data sent through it.

Open Whisper Systems, which has the goal of simplifying private communication, announced the partnership on a post in the company's official blog. The company said that it has been working with WhatsApp for the previous half year to incorporate the TextSecure protocol into the app.

The TextSecure protocol is a strong, open source encryption protocol that the company has been developing for the past three years. It works by scrambling the messages using a cryptographic key that only the user is able to access. Since the key permanently stays within the user's device, the encrypted messages are practically uncrackable externally.

The protocol also uses a feature called "forward secrecy," which creates new encryption keys for every message sent. This means that even if a hacker would be able to access a user's encryption key, only the message that used that key will be compromised. All the other messages are still safe.

The encryption feature will be activated by default for the latest update of the messaging app's Android version. An update for the iOS version of the app incorporating the feature is also expected soon.

Only user-to-user messages for the Android version are encrypted for now, with support for group chats and media messages containing pictures and videos to be rolled out soon.

"We have a ways to go until all mobile platforms are fully supported, but we are moving quickly towards a world where all WhatsApp users will get end-to-end encryption by default," Open Whisper Systems wrote.

End-to-end encryption will deliver complete privacy to WhatsApp users, as the system will mean that WhatsApp will not be able to hand over information contained within WhatsApp messages even if law enforcers request for it.

"Whatsapp is integrating TextSecure into the most popular messaging app in the world, where people exchange billions of messages a day," said Open Whisper Systems creator Moxie Marlinspike.

"I do think this is the largest deployment of end-to-end encryption ever," Marlinspike added.

A spokesperson for WhatsApp confirmed the Open Whisper Systems partnership, but declined to provide any further comments beyond the information contained on the blog post.