Skype’s transformation from a VoIP client to a fully-featured messaging platform continues, with Microsoft today announcing that end-to-end encryption arrives as experimental functionality.

The new feature is called Private Conversations and is available as part of the Skype insider program with beta version for Windows, Linux, Mac, Android, and iOS. Users running the same versions will be able to start private chats with end-to-end encryption for messages, files, and audio messages. At this point, video and audio calls are not supported.

Microsoft uses Signal Protocol by Open Whisper Systems to power Private Conversations, and the company explains that content of the chats is automatically hidden in the chat list and in the notifications that are submitted to users.

Encryption already offered in Skype

Microsoft explains how the new feature works, adding that for the time being, the end-to-end encryption is limited to one-to-one conversations:

“Give it a try by selecting ‘New Private Conversation’ from the compose menu or from the recipient’s profile. After the recipient accepts your invite, all calls and messages in that conversation will be encrypted end-to-end until you choose to end it. You can only participate in a private conversation from a single device at a time. You can switch the conversation to any of your devices, but the messages you send and receive will be tied to the device you’re using at the time.”

Skype already offers AES (Advanced Encryption Standard), which Microsoft says is strong enough because it’s being used by the US government as well.

Obviously, end-to-end encryption is what makes eavesdropping a lot more difficult and the majority of messaging platforms have already embraced it, including services like WhatsApp and Telegram.

Microsoft hasn’t said when it plans to release this feature to all Skype users in the production ring, but given that the majority of services already offer such encryption, it shouldn’t take too long before it happens.