Implement ResidenKeyRequirement

[dIeGoLi]

When creating CredentialCreateOptions we have the possibility to set RequireResidentKey. I observed that when using false, resident credentials are not created, thus usernameless flow is not possible. When set to true i tested on Android Firefox, that registration can be completed and requireResidentKey seems to be ignored, usernameless flow does not work. On android chrome following exception is thrown DOMException: Either the device has received unexpected request parameters, or the device cannot support this request.

W3C standard specifies for Authenticator Selection Criteria that there is a parameter residentKey of type ResidentKeyRequirement with the values discouraged, preferred and required.

So i would like to extend the class AuthenticatorSelection with a property ResidentKeyRequirement ResidentKeyRequirement {get; set; } = ResidentKeyRequirement.Required to enable using this further specification. I already tested the behaviour with residentKey: "preferred" and it works as expected. If resident key is supported it registers as resident key, otherwise not.

Would you accept a pull request regarding this?

[aseigler]

This looks really familiar...I thought I had run into and fixed this on branch demo-update, but I don't see it currently. We would certainly accept a PR here.

[abergs]

Yes, I agree.