WhatsApp has recently beefed up security with enhanced end-to-end encryption. This puts the security for WhatApp as the strongest for a texting app right now.

Related: Facebook’s Acquisition of WhatsApp Is Complete

The implementation of end-to-end encryption doesn’t mean that WhatsApp is the first or only messaging app to adapt the method, but it is the biggest or most mainstream of the apps in that arena to do so.

The increase in security comes thanks to a partnership with Open Whisper Systems. The improved version of the Facebook-owned texting app is currently live on Android, but there’s no word as to an iOS version.

End-to-end encryption makes it impossible for messages to be decrypted by WhatsApp. This means federal and local law enforcement agencies that want access to messages sent via WhatsApp are out of luck.

The origins of the code itself comes from Open Whisper Systems’ work on TextSecure which has proven to be extremely hard to crack. According to Open Whisper’s CTO Moxie Marlinspike, the process of getting TextSecure’s setup to work for WhatsApp took roughly six months.

Sporting over 500 million active users, WhatsApp was acquired by Facebook in last month.