Skype will soon join the likes of Facebook Messenger, Apple's iMessage, and WhatsApp by introducing end-to-end encryption, a method of communication that adds an extra layer to conversations by ensuring only the communicating users can read the messages.

Skype, Microsoft’s messaging service that boasts nearly 300 million months users, will take advantage of the Signal Protocol, a non-federated cryptographic protocol co-authored by Moxie Marlinspike, the founder of Open Whisper Systems, four years ago.

Joshua Lund, a developer with Signal announced the news in a blog on Thursday.

Skype users will be able to use the encryption in a forthcoming feature, Private Conversations, already available to users of Skype Insider, a beta build of the app Microsoft makes available to interested parties on its site.

It’s unclear when the feature will make it to the final build of Skype. For now only 8.13.76.8, the most recent version of Skype Insider for Android, iOS, Linux, Mac, and Windows includes end-to-end encryption. The feature only works if other users have the same version of the app; it does not work for video or group chats yet.

Users will have to work a little harder to user the feature in Skype; it's not being rolled out by default. According to the company users will have to tap or click the "+" icon and select "New Private Conversation." Assuming the user accepts the invitation, a private conversation will start. The conversation will only remain confidential on that device, meaning users can't expect to carry over one chat from their iPhone to their Macbook and expect it to remain encrypted.

While the functionality, at least for the moment, is a bit limited, privacy advocates, like the Electronic Frontier Foundation, called the move a step in the right direction this week while encouraging Microsoft deploy the feature by default.

Communication tools and platforms should implement end-to-end encryption as the default, rather than an option.

— EFF (@EFF) January 12, 2018

Joshua Franco, Head of Technology and Human Rights at Amnesty International had similar sentiments.

“It is about time that Microsoft takes its users’ privacy seriously, and we are now calling on the company to roll out default end-to-end encryption for all Skype communications,” Franco said, “Companies who don’t install full encryption are effectively handing the keys to cyber criminals and intrusive state surveillance agents. As more and more communications move online, it is up to companies to demonstrate they are on the side of human rights – the future of freedom of expression is partly in their hands.”