Conditional mediation TAG security & privacy questionnaire

TAG review requires filling a Security and Privacy questionnaire.

1. What information might this feature expose to Web sites or other parties, and for what purposes is that exposure necessary?

   The Credential Management API exposes credentials previously stored by websites to facilitate authentication. Conditional mediation does not expose any additional information. Sharing credentials with a website still requires user consent.

2. Do features in your specification expose the minimum amount of information necessary to enable their intended uses?

   No additional information is exposed by Conditional Mediation that wasn't already exposed by required mediation. There is a check in place to avoid revealing to the website that the user does not have credentials for it.

3. How do the features in your specification deal with personal information, personally-identifiable information (PII), or information derived from them?

   For Credential Management in general, see the Security and Privacy considerations. Conditional mediation does not change handling of PII.

4. How do the features in your specification deal with sensitive information?

   See 3, Conditional Mediation does not change handling of PII.

5. Do the features in your specification introduce new state for an origin that persists across browsing sessions?

   Conditional Mediation does not introduce state.

6. Do the features in your specification expose information about the underlying platform to origins?

   Availability of Conditional Mediation can reveal that the current combination of browser and OS support the feature.

7. Does this specification allow an origin to send data to the underlying platform?

   No.

8. Do features in this specification enable access to device sensors?

   No.

9. What data do the features in this specification expose to an origin? Please also document what data is identical to data exposed by other features, in the same or different contexts.

   Credentials that can already be discovered through other mediation modes.

10. Do features in this specification enable new script execution/loading mechanisms?

    No.

11. Do features in this specification allow an origin to access other devices?

    No.

12. Do features in this specification allow an origin some measure of control over a user agent’s native UI?

    Conditional Mediation, like required mediation, displays credential information in some form of native UI. This is done to distinguish the UI to select and consent to share a credential with the website from the website UI.

13. What temporary identifiers do the features in this specification create or expose to the web?

    Conditional UI does not introduce new identifiers.

14. How does this specification distinguish between behavior in first-party and third-party contexts?

    Conditional UI does not change how Credential Management treats first-party vs third-party contexts. For a general discussion on credential management, see Cross domain credential access and Origin confusion.

15. How do the features in this specification work in the context of a browser’s Private Browsing or Incognito mode?

    Conditional mediation does not treat incognito in a special way.

16. Does this specification have both "Security Considerations" and "Privacy Considerations" sections?

    https://w3c.github.io/webappsec-credential-management/#security-and-privacy

17. Do features in your specification enable origins to downgrade default security protections?

    No.

18. How does your feature handle non-"fully active" documents?

    No information is shared with the website until the user consents, so that can't happen if the document is not fully active. In practice, a navigator.credentials.get() request will be paused with the promise remaining unresolved, and may be resumed if the document becomes fully active again.