Facebook this week rolled out its message encryption software to all of nearly one billion Facebook Messenger users. The company, which started quietly beta-testing the software in July, only alerted users who recently updated their software to the new feature. End-to-end encryption technology is already the default for WhatsApp, which is owned by Facebook.

Facebook’s “Secret Conversations” will require both the sender and recipient to opt-in to the software in order to use the new Facebook Messenger feature. In order to use “Secret Conversations,” you’ll need to enable the preference in your settings options.

If for some reason you’re happy to let Facebook, law enforcement, or even spies access your messages, you don’t need to do anything. If you’re not happy with that prospect, here’s how to turn on “Secret Conversations” in Facebook Messenger:

1. Select the “Secret Option”

To send an encrypted message, you need to select the “secret” option in the top right of the message composition screen. Like WhatsApp, Facebook Messenger uses encryption software developed by Open Whisper Systems, the nonprofit behind the Signal app.

2. Look for the Clock

After you select “secret,” you’ll see a clock in the bottom right-hand corner of the screen. If you would like the message to destruct, selecting the clock will give you an option to set the message to destruct in between five seconds to a day after it’s opened.

By forcing users to opt-in to the setting, rather than making it the default, Facebook can avoid some of the legal struggles that WhatsApp has faced over the past year. Whatsapp has been caught in a nearly year-long battle with the Brazilian government, with the most recent ban on the app being lifted by the Brazilian Supreme Court in July. The company’s inability to provide encrypted data to officials resulted in the arrest of a Facebook executive in March.

That privacy comes at a cost, though. You’ll get a stripped-down experience with “Secret Conversations” turned on. GIFs, videos, voice calling, and payments are not supported by the secret messages.

Photos via Karlis Dambrans/Flickr