RE: A modest proposal on extensibility - wrap up

Hi Wendy,

The process you describe below may still be a bit heavyweight for the generally understood extensibility needs of a crypto API if it requires publication of new string/enum values on the Errata page before using those values is considered compliant.  Can you please clarify if in this statement:

1. Wherever a string/enum value is defined, insert something like the following: 
 1.1. This specification defines values X, Y, Z 
 1.2.  Implementations MAY support other values 
 1.3. When an extension is made to add a value, a reference should be added to the "Extensions" section

The "should" in 1.3 is supposed to be a SHOULD, a MAY or a MUST?  If it's a SHOULD or MAY, then it's just recommending that extension values be published but their use is not contingent on further W3C process.  If it's a MUST, then use of the new value would be blocked until some W3C process occurs, to publish the (potentially private) extension, which is what we don't want.  So I would like clarification if this is supposed to be a SHOULD, MAY or MUST.  I would argue that MAY is the right thing here, SHOULD I could live with, but MUST is a non-starter.

Thanks,

--bal

-----Original Message-----
From: Wendy Seltzer [mailto:wseltzer@w3.org] 
Sent: Tuesday, October 14, 2014 6:10 PM
To: Mike Jones; Mark Watson; GALINDO Virginie
Cc: Harry Halpin; Richard Barnes; public-webcrypto@w3.org
Subject: Re: A modest proposal on extensibility - wrap up

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On 10/14/2014 08:32 PM, Mike Jones wrote:
> W3C experts – could you tell us practically what it takes to update 
> the errata page for a spec, both process wise and timeline wise?
> Does it require a working group action or is it just someone recording 
> the contents of an e-mailed request on the web page?  Is there a 
> review process or are proposed errata simply recorded as they come in?  
> I’d like to get some sense of how easy/hard this will be to do in 
> practice and who will have the rights to update the page.

Here's the W3C Process on errata:
http://www.w3.org/2004/02/Process-20040205/tr.html#rec-modify


The WG needs to propose changes to appear on errata pages, and to approve them through the full process before new features become normative, That process can go quickly (more quickly under the recent process revision), if the group can get consensus and review quickly.
On the plus side, you have royalty-free patent commitments on those normative extensions.

- --Wendy

> Responding to Mark’s comments, I could imagine someone inventing a new 
> key format, so I’d think that KeyFormat should be a defined extension 
> point. As much as I’m fond of JWK, it may not be the last key format 
> ever.  I’m fine not having usages be an extension point.
> 
> -- Mike
> 
> From: Mark Watson [mailto:watsonm@netflix.com] Sent: Tuesday, October 
> 14, 2014 11:21 AM To: GALINDO Virginie Cc: Harry Halpin; Mike Jones; 
> Richard Barnes; public-webcrypto@w3.org Subject: Re: A modest proposal 
> on extensibility - wrap up
> 
> Virginie,
> 
> Just to re-iterate the two minor points I made in response to 
> Richard's proposal:
> 
> (1) I don't believe we have a need or desire for additional values of 
> the KeyFormat enum or the usages strings (2) The text change to handle 
> the recognized values of other things, with extensibility, is a little 
> more involved that Richard says - to deal for example with 
> parameterized hash algorithms - but this should be ok.
> 
> I could do the editing for this tomorrow.
> 
> ...Mark
> 
> On Tue, Oct 14, 2014 at 8:20 AM, GALINDO Virginie 
> <Virginie.Galindo@gemalto.com<mailto:Virginie.Galindo@gemalto.com>>
> wrote: Hi all,
> 
> It looks like we are in a good direction to move forward on 
> extensibility/errata. Thanks Richard for making that proposal.
> 
> After discussing with Harry and Wendy, we came to the slightly 
> modified proposal. We were thinking about submitting it as part of the 
> proposed resolution to close the extensibility bug.
> 
> ** process for extending W3C specification with new algorithms **
> 
> 1. Wherever a string/enum value is defined, insert something like the 
> following: 1.1. This specification defines values X, Y, Z 1.2.
> Implementations MAY support other values 1.3. When an extension is 
> made to add a value, a reference should be added to the "Extensions" 
> section
> 
> 2. Wherever a string/enum value is used as a branch point, insert 
> something like the following: 2.1. If X... If Y... If Z... 2.2. If 
> another recognized value, process according to that value 2.3. If an 
> unrecognized value, raise an NotSupportedError (or TypeError for 
> enums)
> 
> 3. Add an "Extensions" section as errata to the specification where 
> links can be added to point to extension.
> 
> **
> 
> FYI, errata description in W3C can be found under 
> http://www.w3.org/Consortium/Process/errata

> 
> Hope this is agreeable to you. Virginie
> 
> 
> 
> -----Original Message----- From: Harry Halpin 
> [mailto:hhalpin@w3.org<mailto:hhalpin@w3.org>] Sent: lundi 13 octobre 
> 2014 15:39 To: Mike Jones; Mark Watson; Richard Barnes Cc:
> public-webcrypto@w3.org<mailto:public-webcrypto@w3.org> Subject:
> Re: A modest proposal on extensibility
> 
> 
> 
> On 10/12/2014 09:02 PM, Mike Jones wrote:
>> It's the extra layer of indirection that makes them completely 
>> different and actually solves the problem of being able to list 
>> extensions without modifying the base spec.  If they're equivalent to 
>> you and others, then you should have no problem with the Web page 
>> approach, and it would satisfy Microsoft's extensibility goals.  So 
>> let's do that!
> 
> 
> The list of extensibility algorithms is vetted by the W3C WG and in an 
> official errata.
> 
> I'm also happy to have the W3C/WG maintain a web-page with proposed 
> extensions that have not yet made it to the official errata. That is 
> at least good house-keeping as a pointer to proposals that have not 
> gone through the WG.
> 
> I think either of these solves Boris' issue but I think Ryan and 
> Richard prefer having the errata as official.
> 
> I think there is no huge difference in practice. Ryan's argument, as I 
> understand it, is that keeping any forward references in an errata 
> makes it easier for implementers to know what is really out there in 
> terms of algorithms.
> 
> I would just like to close this while keeping extensibility for curves 
> like Curve25519 that aren't in main spec.
> 
> 
>> -- Mike
> 
>> -----Original Message----- From: Harry Halpin 
>> [mailto:hhalpin@w3.org<mailto:hhalpin@w3.org>] Sent: Sunday, October 
>> 12, 2014 10:03 AM To: Mike Jones; Mark Watson; Richard Barnes Cc:
>> public-webcrypto@w3.org<mailto:public-webcrypto@w3.org> Subject:
>> Re: A modest proposal on extensibility
> 
> 
> 
>> On 10/11/2014 06:40 PM, Mike Jones wrote:
>>> I’d been travelling internationally and so am just now getting to 
>>> this.  The problem with Richard’s proposal is that updating the 
>>> “Extensions” section he proposed would still require updating the 
>>> specification for every extension – defeating the purpose.  A slight 
>>> variant of it could work however.  If the “Extensions” section 
>>> instead pointed to a Web page maintained by the W3C that was updated 
>>> every time that an extension was defined, then only the Web page 
>>> would have to be updated and not the base spec. That would achieve 
>>> the purpose of being able to create extensions without modifying the 
>>> base spec *and* provide an actionable way for implementers to locate 
>>> extensions.
> 
> 
>> I see "references to extensions in errata" as just one layer of 
>> indirection less than "link to web-page with references in errata". 
>> Thus, they are functionally equivalent in my book, with the only 
>> point that it's a bit harder to update errata (but hopefully W3C will 
>> make this easier in the near-term future) but also easier for readers 
>> of the spec to find the references.
> 
>>> As for the other topic of extending key formats, I believe that we 
>>> already know that this is necessary.  For instance, 25519 keys are 
>>> expressed in a different format than NIST EC keys.
>>> That alone is enough of an existence proof to demonstrate that we 
>>> must enable key format extensions.
> 
>>> -- Mike
> 
>>> From: Mark Watson
>>> [mailto:watsonm@netflix.com<mailto:watsonm@netflix.com>] Sent:
>>> Friday, October 10, 2014 2:09 PM To: Richard Barnes Cc: Harry 
>>> Halpin; public-webcrypto@w3.org<mailto:public-webcrypto@w3.org>
>>> Subject: Re: A modest proposal on extensibility
> 
> 
> 
>>> Sent from my iPhone
> 
>>> On Oct 10, 2014, at 1:55 PM, Richard Barnes 
>>> <rlb@ipv.sx<mailto:rlb@ipv.sx<mailto:rlb@ipv.sx>>> wrote: On Fri, 
>>> Oct 10, 2014 at 4:34 PM, Mark Watson 
>>> <watsonm@netflix.com<mailto:watsonm@netflix.com><mailto:watsonm@netf
>>> lix.com<mailto:watsonm@netflix.com>>>
>>> wrote: This seems fine, except: - we have discussed key format and 
>>> agreed we do not want / need extensibility for this - no one has 
>>> suggested we need an extensibility point for usages
> 
>>> I agree that key formats are low priority for extension, but I'm a 
>>> little surprised that we would forego it entirely.  I guess it just 
>>> means that extending the set would need a spec update (to add 
>>> extensibility), which seems OK.
> 
>>> I'd suggest that we include a table which lists all the WebCrypto 
>>> algorithms and for each one lists the
>>> specification(s) that define that algorithm. The initial value for 
>>> the existing algorithms will be 'This specification' but we will add 
>>> values - through the errata process - as we write extension 
>>> specifications.
> 
>>> The definition of 'other specifications' will be revised to be 
>>> restricted to those specifications listed in the table.
> 
>>> This seems fine to me.
> 
>>> The only remaining issue is whether we should arrange the procedures 
>>> for import / export of keys for algorithms parameterized by a hash 
>>> function such they it does not appear that import / export for the 
>>> existing cases can be overridden, even though we constrain 
>>> extensions to definition of new hash algorithm values in prose.
> 
>>> That was what I was trying to get at with the proposed branch
>>> structure: -- One of the hash functions defined in this spec... -- 
>>> Another one you recognize... -- Error
> 
>>> It's not quite as simple as that in the specification text as we 
>>> want to defer to the extension specification exactly how the new 
>>> hash function is signalled, including the possibility that it is 
>>> parameterized. But still, we can do this.
> 
>>> ...Mark
> 
> 
>>> --Richard
> 
> 
>>> ...Mark
> 
>>> Sent from my iPhone
> 
>>>> On Oct 10, 2014, at 8:45 AM, Harry Halpin 
>>>> <hhalpin@w3.org<mailto:hhalpin@w3.org><mailto:hhalpin@w3.org<mailto
>>>> :hhalpin@w3.org>>>
>>>> wrote:
>>>> 
> 
> 
>>>>>> On 10/10/2014 05:27 PM, Richard Barnes wrote: Talking to a few 
>>>>>> folks off-list, it seems like the extensibility discussion has 
>>>>>> gotten a bit muddled.  The goal of this message is to try to 
>>>>>> focus/clarify with a specific proposal. It sounds like the 
>>>>>> general desiderata people have are: 1. To make it possible to add 
>>>>>> new values for strings/enums without major spec surgery 2. To 
>>>>>> make it easy for developers to find extensions
>>>>>> 
>>>>>> To that end, I would like to propose a way forward for
>>>>>> extensibility:
>>>>>> 
>>>>>> <proposed-plan>
>>>>>> 
>>>>>> 1. Wherever a string/enum value is defined, insert something like 
>>>>>> the following: 1.1. This specification defines values X, Y, Z 
>>>>>> 1.2. Implementations MAY support other values 1.3. When an 
>>>>>> extension is made to add a value, a reference should be added to 
>>>>>> the "Extensions"
>>>>>> section
>>>>>> 
>>>>>> 2. Wherever a string/enum value is used as a branch point, insert 
>>>>>> something like the following: 2.1. If X...
>>>>>> If Y... If Z... 2.2. If another recognized value, process 
>>>>>> according to that value 2.3. If an unrecognized value, raise an 
>>>>>> NotSupportedError (or TypeError for enums)
>>>>>> 
>>>>>> 3. Add an "Extensions" section to the bottom of the spec, where 
>>>>>> links can be added to point to extension specs.
> 
>>> As noted on Bugzilla, as long as Extensions are in Errata, that's 
>>> fine by W3C Process I believe.
> 
>>> cheers, harry
> 
>>>>>> 
>>>>>> </proposed-plan>
>>>>>> 
>>>>>> Does that overall approach seem agreeable to people?
>>>>>> 
>>>>>> --Richard
>>>> 
> 
> 
> 
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- --
Wendy Seltzer -- wseltzer@w3.org +1.617.715.4883 (office) Policy Counsel and Domain Lead, World Wide Web Consortium (W3C)
http://wendy.seltzer.org/        +1.617.863.0613 (mobile)

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Received on Wednesday, 15 October 2014 13:56:21 UTC