[Disclaimer: This issue is one of several being filed to capture discussions that began either on #638, on #689, or at the most recent F2F]

The concept of “Trusted UI” is what allows User Agents to display a UI to end users on which sensitive information can be displayed and interacted with such that a website cannot snoop on it and cannot spoof it. Some features which use Trusted UI are user consent prompts, URL bars, navigation controls, favorite/bookmarks, and many more.

In 2D browsers, Trusted UI is presented either exclusively around the outside of a web page’s visual container or overlapping with it partially. In the context of an immersive experience, the definition of a “Trusted Immersive UI” is a bit more complex due to the fact there is no “outside” of immersive content; all pixels the user sees are rendered by the immersive content.

Various User Agents are exploring variations of Trusted Immersive UI, and as such WebXR should probably have a stance on the minimum requirements of these UIs to ensure they can meet an agreed upon security bar. For example, one already agreed upon aspect of WebXR is that there must always be a hardware button or dedicated gesture that users can rely on to bring them out of an immersive browsing session.

This GitHub issue is to track the discussion of what this bar should be. These are some of the ideas I recall folks mentioning:

• On devices with motion controllers with buttons, a dedicated button press/hold could be used to pull up the Trusted UI. When a trusted UI popup is needed, interacting with the same dedicated hardware button before displaying the content could be required. (e.g. “This browser needs your attention. Please press the Application button.”). Alternatively, it could go straight into presenting the request but require the dedicated hardware button to make a selection (e.g. “This site is requesting your permission to blahdiblah. Press the Application button to see your choices”)
• Displaying a sigil/totem that the User Agent knows about but the website does not. This approach would probably require disabling MR video and photo capture while the sigil is displayed.
• Regardless of how the UI is presented, frame data will need to be modified in some way (significantly throttled, quantized, rounded, etc) when Trusted Immersive UI is displayed to ensure the site cannot sniff password or URL entry.

I’m sure I’ve forgotten some and there are likely others not mentioned yet. So please please chime in with any information you can share about the approach your products are taking, and from there we’ll work on distilling the the information and establishing a consistent baseline.