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Re: TLS Logout - was: window.cipher HTML crypto API draft spec

From: Anders Rundgren <anders.rundgren@telia.com>
Date: Sat, 06 Aug 2011 18:01:47 +0200
Message-ID: <4E3D656B.5010505@telia.com>
To: David Dahl <ddahl@mozilla.com>
CC: Henry Story <henry.story@bblfish.net>, whatwg@lists.whatwg.org, public-identity@w3.org
On 2011-08-06 17:53, David Dahl wrote:
> Henry:
> 
> Please pardon my ignorance and thank you for the example. crypto.logout() 
> is probably the least known window API of the bunch.

I guess you are quite right!

> In 10 years of web development I have never encountered its use. 
> I knew there was a logout() method, I was unsure how it was used.

It would actually be quite interesting to hear why and when it was implemented.
It was presumably an important .GOV customer who asked for it.  Or maybe
it was just somebody with Netscape that needed it?

http://xkcd.com/927

Best
Anders

> 
> Regards,
> 
> David
> 
> ----- Original Message -----
> From: "Henry Story" <henry.story@bblfish.net>
> To: "David Dahl" <ddahl@mozilla.com>
> Cc: whatwg@lists.whatwg.org, public-identity@w3.org
> Sent: Saturday, August 6, 2011 10:27:15 AM
> Subject: Re: TLS Logout - was: window.cipher HTML crypto API draft spec
> 
> 
> On 6 Aug 2011, at 17:01, David Dahl wrote:
> 
>> Henry,
>>
>> Your login and logout concept is a perhaps parallel to the sessions functionality in Mozilla's Identity work: https://wiki.mozilla.org/Identity/Verified_Email_Protocol/Latest-Session
> 
> David,
> 
>    the logout() method I am speaking of is not a concept. It is part of Mozilla and Internet Explorer and works. The Javascript is the following
> 
> ---------
> 
> function logout(elem) {
>     if (document.all == null) {
>        if (window.crypto) {
>            try{
>                window.crypto.logout();
>                return false; //firefox ok -- no need to follow the link
>            } catch (err) {//Safari, Opera, Chrome -- try with tis session breaking
>            }
>        } else { //also try with session breaking
>        }
>     } else { // MSIE 6+
>        document.execCommand('ClearAuthenticationCache');
>        return false;
>     };
>     return true
>  }
> 
> function login(elem)  { logout(elem) }
> 
> -----
> 
> Then you can just put the following html in your page
> 
> <a href={"/user/joe/control-panel"}>Joe</a>|<a href="/logout" onclick="return logout();">logout</a>
> 
> And Firefox and I believe MS will logout. I will have a server up demonstrating that in the next few days.
> This is the right way to close a TLS session. The browser then can ask the user to choose a new certificate, certain that this was indeed what the user wanted.
> 
> So the above is at a different layer from what Mozilla is doing with the verified e-mail protocol, since Mozilla is working on the verified e-mail protocol but already has the logout() method. 
> 
> If the verified e-mail protocol is the same as what is now known as BrowserId, then I also support work in that area. But there are many organisations that would find TLS client certificate usage dramatically improved if they could just help the browser log out cleanly at the TLS layer. Specifying this can't be that much work, and would help guide people in the right direction here.
> 
> Henry
> 
> 
> 
> 
> 
>>
>>
>> Cheers,
>>
>> David
>>
>> ----- Original Message -----
>> From: "Henry Story" <henry.story@bblfish.net>
>> To: "David Dahl" <ddahl@mozilla.com>
>> Cc: whatwg@lists.whatwg.org, public-identity@w3.org
>> Sent: Saturday, August 6, 2011 9:05:15 AM
>> Subject: Re: TLS Logout - Re: [whatwg] window.cipher HTML crypto API draft spec
>>
>>
>> On 6 Aug 2011, at 16:01, David Dahl wrote:
>>
>>> Henry:
>>>
>>> There is no reason a login and logout (that work properly) cannot be added to window.crypto, however, the scope and focus of 'DOMCrypt' is as narrowly-defined as possible. Adding features like this would only slow progress.
>>
>> David, this is a really essential feature. If you are worried that one method call can slow progress of DOMCrypt, then where do you think that should be standardised?
>>
>> Or perhaps someone else has an opinion here?
>>
>> Henry
>>
>>>
>>> Regards,
>>>
>>> David
>>>
>>> ----- Original Message -----
>>> From: "Henry Story" <henry.story@bblfish.net>
>>> To: "David Dahl" <ddahl@mozilla.com>
>>> Cc: whatwg@lists.whatwg.org, public-identity@w3.org
>>> Sent: Saturday, August 6, 2011 6:16:22 AM
>>> Subject: TLS Logout - Re: [whatwg] window.cipher HTML crypto API draft spec
>>>
>>> Hi,
>>>
>>> I have been looking at how a client can logout from a TLS session recently, so that if a user
>>> sends the wrong certificate to the server, the server can propose a way for the user to choose a 
>>> different one. 
>>>
>>> The correct way to do this would be to build it right into the browser, so that at all times the user is in control of his Persona, i.e. to extend Aza Raskin's work to the TLS layer [1]. 
>>>
>>> The second best way is to have a Javascript API to logout the user, that web page authors can use to offer this feature. Firefox and Internet explorer have such an API. The Firefox one is described in the WebCrypto API [2] by Channy Yun, which was discussed on this list recently. 
>>>
>>> The code to run both in IE and Firefox is quite simple. I submitted a bug report to Chrome with the 
>>> code to suggest that they could implement this there too
>>>
>>> http://code.google.com/p/chromium/issues/detail?id=90676
>>>
>>> But they want the DOMCrypt spec approval before implementing. Is that something that could be added to DOMCrypt? Or should one look somewhere else? 
>>>
>>> This is a really simple function, but it is so useful. 
>>>
>>> Henry
>>>
>>>
>>> [1] http://www.azarask.in/blog/post/identity-in-the-browser-firefox/
>>> [2] http://html5.creation.net/webcrypto-api/
>>>   (the login method does not work currently in Firefox, on has to use logout, where the connection then asks the client for a certificate)
>>>
>>>
>>>
>>>
>>>
>>> On 20 May 2011, at 17:04, David Dahl wrote:
>>>
>>>> Hello WHATWG members,
>>>>
>>>> With user control and privacy in mind, I have created a spec and an implementation for an easy to use cryptography API called DOMCrypt. This API will provide each web browser window with a 'cipher' property that facilitates:
>>>>
>>>> * asymmetric encryption key pair generation
>>>> * public key encryption 
>>>> * decryption
>>>> * signature generation
>>>> * signature verification
>>>> * hashing
>>>> * easy public key discovery via meta tags
>>>>
>>>> I have created a Firefox extension that implements all of the above, and am working on an experimental patch that integrates this API into Firefox.
>>>>
>>>> The draft spec is here: https://wiki.mozilla.org/Privacy/Features/DOMCryptAPISpec/Latest
>>>>
>>>> The project originated in an extension I wrote, the home page is here: http://domcrypt.org
>>>>
>>>> The source code for the extension is here: https://github.com/daviddahl/domcrypt
>>>>
>>>> The Mozilla bugs are here: 
>>>> https://bugzilla.mozilla.org/show_bug.cgi?id=649154
>>>> https://bugzilla.mozilla.org/show_bug.cgi?id=657432
>>>>
>>>> You can test the API by installing the extension hosted at domcrypt.org and addons.mozilla.org, and going to http://domcrypt.org
>>>>
>>>> Best Regards,
>>>>
>>>> David Dahl
>>>>
>>>> Firefox Engineer, Mozilla Corp.
>>>
>>> Social Web Architect
>>> http://bblfish.net/
>>>
>>
>> Social Web Architect
>> http://bblfish.net/
>>
> 
> Social Web Architect
> http://bblfish.net/
> 
> 
> 
Received on Saturday, 6 August 2011 16:02:45 GMT

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