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Re: The ability to automatically upgrade a reference to HTTPS from HTTP

From: jose <jose.kahan@w3.org>
Date: Wed, 27 Aug 2014 13:17:01 +0200
To: Tim Berners-Lee <timbl@w3.org>
Cc: Public TAG List <www-tag@w3.org>, SW-forum Web <semantic-web@w3.org>
Message-ID: <20140827111701.GA9819@kiribati.inrialpes.fr>
Hi Tim,

It makes sense to me that both http: and https: point to the same resource.
This aligns to one of the proposals I had made for our server to 
support either http or https requests for the same resource, but 
do force a switch to https for protected resources.

Some extra thoughts.

* Caching / MIM

It would be good that the browser knows this so that it caches only once
the resource. Today, at least in firefox, both are considered different
linked-content resources (e.g. an image) and have two different cache entries. 
You are making two requests for the same one. If we consider that both 
http: and https: point to the same resource, it would be good to share the 
same cache entry and it could even speed up the requests. 

On the other hand, if you have retrieved one of the linked contents (an
image again) using http and then go to an https that includes the same
image, you could potentially be open to a man-in-the-middle attack as
the image came thru http. This could potentially be used to inject 
content to your browser and was one of the reasons why mixed content
warnings appear.

So it seems to be that here you'd like to have a priority of origin source,
saying that for the same resource, the most restrictive one (https) should
override the other one.

* Built-in browser https "upgrade" feature

It would be good that the browsers have this as in-built. A kind of
"protocol override" so that you assume that the protocol you used to
request the page is the same one for the linked-in resources that belong
to the same server. 

This is important for legacy content that can't be updated.

If you're using http to request a page that includes resources using https,
you probably don't want to downgrade those resources. You do want to do
that when requesting a page thru https that includes http resources.

* Servers supporting HTTPS

The popular add-on https-everywhere assumes that all servers support
https for the same resources. This makes the browser take the initiative
to request everything using https, including the linked content. However,
when a server supports only http, this adds to the network traffic as
it's a hit-and-miss approach. I don't think they are using HTTPS OPTIONS
to find out the capabilities of a server.

If a server has self-signed certificates, it's more confusing to the
layman to see the "untrusted certificate" pop-up than to have used 
http directly. Not everyone with a web site will buy an official certificate,
that's for sure.

So my question here is if the browsers should take the initiative to use
https or should it be the initiative of the server (like we do with
switch-ssl on our servers today).

--jose
Received on Wednesday, 27 August 2014 11:17:32 UTC

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