Re: [web-nfc] Suggest a permission UI flow

Since we seem to be getting stuck and going in circles on the details 
here, let me try to rephrase the mozilla requirements at a higher 
level.

* We should only ask the user questions that they can reasonably make 
an informed decision on and where the consequences of saying "yes" is 
clear. Things like "do you want to share your location with this 
website" and "do you want this website to be able to use your camera 
and microphone" have understandable consequences to users. Things like
 "do you want to allow this website to write to this NFC tag" or "do 
you want to allow this website to send an NFC message to this P2P 
peer" does not have understandable consequences to the user.
* We need to define when a prompt will be displayed and when it won't.
 Simply saying "UA policy" is not good enough for two reasons.
 * Websites care a lot about when a prompt is displayed. If one is 
displayed when they didn't expect it to, they consider that broken 
behavior.
 * If a UA automatically deny a particular action when the website did
 expect a prompt to displayed, that effectively means that that 
functionality is broken to the website.
* This does mean that we have a problem if two different browsers want
 to prompt for different things. However for every other web 
specification created so far we have been able to resolve those 
differences. So I have confidence that we can resolve that here too.
* If we can't make a particular NFC read/write/message-exchange safe 
to all websites everywhere, including evil ones that are trying to 
hack the user, then we need someone to assert that a given action is 
safe. This means that either the user has to make that assertion, 
which does not seem possible to me per the first bullet, or the NFC 
tag needs to indicate what is safe and what isn't. For network 
requests we solve this using patterns like CORS and WebSocket which 
include explicit messages about which website can take what actions 
against a given server.
* If we are relying on tags to indicate which actions are safe and 
which ones are not, then should use a very explicit format. One thing 
to be very careful of is if there are existing NFC tags out there that
 use the same format, then those could accidentally look like they are
 opting in to allowing a particular action even though that was not 
the intent of the person creating the NFC tag.

My concern with using a URL in the ID field as the way to indicate 
that an otherwise unsafe action is safe, is that the NDEF spec says 
that the ID field *always* includes a URL. But maybe I'm not 
understanding the thinking here.

-- 
GitHub Notif of comment by sicking
See https://github.com/w3c/web-nfc/issues/3#issuecomment-133156045

Received on Thursday, 20 August 2015 20:04:55 UTC