Archiving, with permission of all those involved, and with apologies
for having let this turn into a technical discussion off-list.
Mark's message (the topmost one) includes a number of interesting
design points, that should be further pursued.
Regards,
--
Thomas Roessler, W3C <[EMAIL PROTECTED]>
Begin forwarded message:
From: "Priestley, Mark, VF-Group" <[EMAIL PROTECTED]>
Date: 26 September 2008 15:12:28 CEDT
To: "Thomas Roessler" <[EMAIL PROTECTED]>, "Arthur Barstow" <[EMAIL PROTECTED]
>
Cc: "ext Marcos Caceres" <[EMAIL PROTECTED]>, "Frederick
Hirsch" <[EMAIL PROTECTED]>, "Arve Bersvendsen" <[EMAIL PROTECTED]
>
Subject: RE: DRAFT: Seeking feedback regarding Widgets Digital
Signatures spec
Apologies for joining the discussion late.
I'm in agreement with what has been communicated so far. My opinion
would be that support for SHA-256 for Widgets 1.0 would represent the
good choice called for by Thomas.
In terms of a good idea of how to change from one algorithm to another
at a later point in time, IMHO this is not an easy problem to solve.
The
main problem is supporting legacy devices. This will inevitably mean
that you need to sign all content using both algorithms for the
migration period, which may be quite some while and will be a real
pain.
During this time you'll also need to be able to tell which algorithms
the consuming device supports and send it the right content. Being
able
to update the widget engine OTA will help but can't be relied on. (I'm
sure this is all common knowledge but I thought it was worth repeating
as it's something that will impact Operators particularly acutely)
My feeling therefore tends to be that it is prudent to mandate support
more than one algorithm as early as possible (although actually in our
case I'm starting to think that mandating support for SHA-1 is of
little
value if we are also planning to mandate support of SHA-256) but I'm
aware that this is not always an attractive proposal from an
implementer
or testers perspective.
Thanks,
Mark
-----Original Message-----
From: Thomas Roessler [mailto:[EMAIL PROTECTED]
Sent: 25 September 2008 18:44
To: Arthur Barstow
Cc: ext Marcos Caceres; Frederick Hirsch; Priestley, Mark, VF-Group;
Arve Bersvendsen
Subject: Re: DRAFT: Seeking feedback regarding Widgets Digital
Signatures spec
I'm not sure that the requirement I gave is one that would lead to
changes to the widget requirements spec -- it's more a general design
principle about using cryptographic algorithms.
The fundamental point is that you need some useful migration story
from
one hash algorithm to another one. XML Signature has that, since it
identifies all algorithms by URI. So, unless you do something on your
own and just say in the spec "this is the sha-foo hash of the
following
data" without identifying the algorithm in the document, you should be
fine.
The second point is, again, just the way in which you usually get
interoperability in a space where you have choices: Make some good
choices (maybe just *one* choice) for the purposes of a specific spec,
and be sure you have an idea how to change that later on.
Hope this clarifies matters,
--
Thomas Roessler, W3C <[EMAIL PROTECTED]>
On 25 Sep 2008, at 19:33, Arthur Barstow wrote:
Good question. Let's see what the domain experts say.
My take is:
* The first sentence in the current text will need to be updated to
reflect req #1 from Thomas.
* Regarding Thomas' req #2, perhaps that doesn't need to be an
explicit requirement but something we need to address in the spec.
It feels too much like a statement about the usage/deployment of XML
Signature rather than a high-level req.
-AB
On Sep 25, 2008, at 10:49 AM, ext Marcos Caceres wrote:
On Thu, Sep 25, 2008 at 3:06 PM, Thomas Roessler <[EMAIL PROTECTED]> wrote:
totally, yes.
So there are really two requirements here:
1. Do not use sha-256 implicitly, anywhere, so you can change
later on.
2. Pick a decent set of algorithms.
Does that means that R43. Support for Multiple Message Digest
Algorithms needs to be changed? it currently reads:
"A conforming specification MUST recommend that where the integrity
of
data is protected using a message digest, it MUST be possible to use
the SHA-1 message digest algorithm or the SHA-256 message digest
algorithm. Due to known weaknesses in the SHA-1 algorithm and the
expected lifetime of implementations, a conforming specification
MUST
strongly recommend the use of SHA-256 to ensure that the overall
security of the solution is maintained."
--
Marcos Caceres
http://datadriven.com.au
Begin forwarded message:
From: Thomas Roessler <[EMAIL PROTECTED]>
Date: 25 September 2008 19:43:59 CEDT
To: Arthur Barstow <[EMAIL PROTECTED]>
Cc: ext Marcos Caceres <[EMAIL PROTECTED]>, "Frederick
Hirsch" <[EMAIL PROTECTED]>, "Mark Priestley" <[EMAIL PROTECTED]
>, "Arve Bersvendsen" <[EMAIL PROTECTED]>
Subject: Re: DRAFT: Seeking feedback regarding Widgets Digital
Signatures spec
I'm not sure that the requirement I gave is one that would lead to
changes to the widget requirements spec -- it's more a general
design principle about using cryptographic algorithms.
The fundamental point is that you need some useful migration story
from one hash algorithm to another one. XML Signature has that,
since it identifies all algorithms by URI. So, unless you do
something on your own and just say in the spec "this is the sha-foo
hash of the following data" without identifying the algorithm in the
document, you should be fine.
The second point is, again, just the way in which you usually get
interoperability in a space where you have choices: Make some good
choices (maybe just *one* choice) for the purposes of a specific
spec, and be sure you have an idea how to change that later on.
Hope this clarifies matters,
--
Thomas Roessler, W3C <[EMAIL PROTECTED]>
On 25 Sep 2008, at 19:33, Arthur Barstow wrote:
Good question. Let's see what the domain experts say.
My take is:
* The first sentence in the current text will need to be updated to
reflect req #1 from Thomas.
* Regarding Thomas' req #2, perhaps that doesn't need to be an
explicit requirement but something we need to address in the spec.
It feels too much like a statement about the usage/deployment of
XML Signature rather than a high-level req.
-AB
On Sep 25, 2008, at 10:49 AM, ext Marcos Caceres wrote:
On Thu, Sep 25, 2008 at 3:06 PM, Thomas Roessler <[EMAIL PROTECTED]> wrote:
totally, yes.
So there are really two requirements here:
1. Do not use sha-256 implicitly, anywhere, so you can change
later on.
2. Pick a decent set of algorithms.
Does that means that R43. Support for Multiple Message Digest
Algorithms needs to be changed? it currently reads:
"A conforming specification MUST recommend that where the
integrity of
data is protected using a message digest, it MUST be possible to use
the SHA-1 message digest algorithm or the SHA-256 message digest
algorithm. Due to known weaknesses in the SHA-1 algorithm and the
expected lifetime of implementations, a conforming specification
MUST
strongly recommend the use of SHA-256 to ensure that the overall
security of the solution is maintained."
--
Marcos Caceres
http://datadriven.com.au
Begin forwarded message:
From: Arthur Barstow <[EMAIL PROTECTED]>
Date: 25 September 2008 19:33:17 CEDT
To: ext Marcos Caceres <[EMAIL PROTECTED]>
Cc: "Thomas Roessler" <[EMAIL PROTECTED]>, "Frederick Hirsch" <[EMAIL PROTECTED]
>, "Mark Priestley" <[EMAIL PROTECTED]>, "Arve
Bersvendsen" <[EMAIL PROTECTED]>
Subject: Re: DRAFT: Seeking feedback regarding Widgets Digital
Signatures spec
Good question. Let's see what the domain experts say.
My take is:
* The first sentence in the current text will need to be updated to
reflect req #1 from Thomas.
* Regarding Thomas' req #2, perhaps that doesn't need to be an
explicit requirement but something we need to address in the spec.
It feels too much like a statement about the usage/deployment of XML
Signature rather than a high-level req.
-AB
On Sep 25, 2008, at 10:49 AM, ext Marcos Caceres wrote:
On Thu, Sep 25, 2008 at 3:06 PM, Thomas Roessler <[EMAIL PROTECTED]> wrote:
totally, yes.
So there are really two requirements here:
1. Do not use sha-256 implicitly, anywhere, so you can change
later on.
2. Pick a decent set of algorithms.
Does that means that R43. Support for Multiple Message Digest
Algorithms needs to be changed? it currently reads:
"A conforming specification MUST recommend that where the integrity
of
data is protected using a message digest, it MUST be possible to use
the SHA-1 message digest algorithm or the SHA-256 message digest
algorithm. Due to known weaknesses in the SHA-1 algorithm and the
expected lifetime of implementations, a conforming specification MUST
strongly recommend the use of SHA-256 to ensure that the overall
security of the solution is maintained."
--
Marcos Caceres
http://datadriven.com.au
Begin forwarded message:
From: "Marcos Caceres" <[EMAIL PROTECTED]>
Date: 25 September 2008 16:49:30 CEDT
To: "Thomas Roessler" <[EMAIL PROTECTED]>
Cc: "Frederick Hirsch" <[EMAIL PROTECTED]>, "Arthur
Barstow" <[EMAIL PROTECTED]>, "Mark Priestley" <[EMAIL PROTECTED]
>, "Arve Bersvendsen" <[EMAIL PROTECTED]>
Subject: Re: DRAFT: Seeking feedback regarding Widgets Digital
Signatures spec
On Thu, Sep 25, 2008 at 3:06 PM, Thomas Roessler <[EMAIL PROTECTED]> wrote:
totally, yes.
So there are really two requirements here:
1. Do not use sha-256 implicitly, anywhere, so you can change later
on.
2. Pick a decent set of algorithms.
Does that means that R43. Support for Multiple Message Digest
Algorithms needs to be changed? it currently reads:
"A conforming specification MUST recommend that where the integrity of
data is protected using a message digest, it MUST be possible to use
the SHA-1 message digest algorithm or the SHA-256 message digest
algorithm. Due to known weaknesses in the SHA-1 algorithm and the
expected lifetime of implementations, a conforming specification MUST
strongly recommend the use of SHA-256 to ensure that the overall
security of the solution is maintained."
--
Marcos Caceres
http://datadriven.com.au
Begin forwarded message:
From: Frederick Hirsch <[EMAIL PROTECTED]>
Date: 25 September 2008 16:07:28 CEDT
To: "ext Thomas Roessler" <[EMAIL PROTECTED]>
Cc: Arthur Barstow <[EMAIL PROTECTED]>, Marcos Caceres <[EMAIL PROTECTED]
>, Mark Priestley <[EMAIL PROTECTED]>, Arve Bersvendsen <[EMAIL PROTECTED]
>
Subject: Re: DRAFT: Seeking feedback regarding Widgets Digital
Signatures spec
+1
and maybe picking one algorithm now is simple and the way to go, but
in future a new edition might change the algs
(e.g. someone is going to have to think about versioning, as usual.)
regards, Frederick
Frederick Hirsch
Nokia
On Sep 25, 2008, at 10:06 AM, ext Thomas Roessler wrote:
totally, yes.
So there are really two requirements here:
1. Do not use sha-256 implicitly, anywhere, so you can change later
on.
2. Pick a decent set of algorithms.
-- Thomas Roessler, W3C <[EMAIL PROTECTED]>
On 25 Sep 2008, at 16:03, Frederick Hirsch wrote:
indeed, but the SHA-1 risk is not the last risk we will ever see...
regards, Frederick
Frederick Hirsch
Nokia
On Sep 25, 2008, at 9:56 AM, ext Thomas Roessler wrote:
Frederick,
to your first point, they'll need to agree on some set of
algorithms to get interoperability for widgets, as a platform.
Regards,
--
Thomas Roessler, W3C <[EMAIL PROTECTED]>
On 25 Sep 2008, at 15:52, Frederick Hirsch wrote:
one question I have is the following:
XML Signature makes an effort to allow the specification of
algorithm with the data, thus allowing it to be self-specifying
and modifiable. Why do you feel a requirement to limit to a
single algorithm? What happens if you select RSA-SHA256 and then
a need is seen for SHA-512 or an alternative to RSA due to some
new attack or weakness?
Why not leverage the flexibility of XML Signature to allow
different algorithms, along lines of Receiver MUST support RSA-
SHA1, RSA-SHA256 "or better" and Sender MUST support RSA-SHA256
etc But perhaps I am anticipating WG discussion.
Draft looks good, maybe
s/Anyhow, d/D/
#2 s/do/should
Perhaps add #4, is there sense is supporting more than one
algorithm?
regards, Frederick
Frederick Hirsch
Nokia
On Sep 25, 2008, at 9:44 AM, Arthur Barstow wrote:
Below is my DRAFT e-mail to the XML Sec WG regarding Issue #22.
Is this OK? If not, please send suggested changes that will
make it OK.
FYI, I discussed this impending e-mail with Frederick and he
was agreeable to me including him on this Draft email.
-Thanks, Art
=== START DRAFT
To: [EMAIL PROTECTED]
Cc: public-webapps@w3.org
Subject: Seeking feedback regarding Widgets Digital Signatures
spec
Frederick, All,
As you may know, the Web Applications WG [WebApps] is working
on a Digital Signature specification for "Widgets" (see
[Widgets] for a definition of Widget in this context).
The FPWD of our Digital Signature spec is at [DigSig-TR] and
the latest Editor's Draft is available at [DigSig-ED].
Anyhow, during our August f2f meeting, we discussed what we
call Issue #22 - "Is sha1 as a DigestMethod strong enough for
Widgets digital signatures?" [Issue-22]. At then end of this
discussion [Issue-22-Discuss] I agreed to the following action:
[[
Ask the XML Sec WG "what algorithm do you recommend we use and
what identifier should we use for it?
]]
Our questions are:
1. What (if any) issues do you foresee if we require support
for SHA-256 (rather than SHA-1)?
2. What algorithm do we use?
3. What identifier do we use for the algorithm?
-Regards, Art Barstow
Co-Chair of the WebApps WG
[WebApps] <http://www.w3.org/2008/webapps/wiki/Main_Page>
[Widgets] <http://www.w3.org/TR/widgets-reqs/#introduction>
[DigSig-TR] <http://www.w3.org/TR/widgets-digsig/>
[DigSig-ED] <http://dev.w3.org/2006/waf/widgets-digsig/>
[Issue-22] <http://www.w3.org/2008/webapps/track/issues/22>
[Issue-22-Discuss] <http://www.w3.org/2008/08/27-wam-minutes.html#item07
>
Begin forwarded message:
From: Thomas Roessler <[EMAIL PROTECTED]>
Date: 25 September 2008 16:06:09 CEDT
To: Frederick Hirsch <[EMAIL PROTECTED]>
Cc: Arthur Barstow <[EMAIL PROTECTED]>, Marcos Caceres <[EMAIL PROTECTED]
>, Mark Priestley <[EMAIL PROTECTED]>, Arve Bersvendsen <[EMAIL PROTECTED]
>
Subject: Re: DRAFT: Seeking feedback regarding Widgets Digital
Signatures spec
totally, yes.
So there are really two requirements here:
1. Do not use sha-256 implicitly, anywhere, so you can change later
on.
2. Pick a decent set of algorithms.
-- Thomas Roessler, W3C <[EMAIL PROTECTED]>
On 25 Sep 2008, at 16:03, Frederick Hirsch wrote:
indeed, but the SHA-1 risk is not the last risk we will ever see...
regards, Frederick
Frederick Hirsch
Nokia
On Sep 25, 2008, at 9:56 AM, ext Thomas Roessler wrote:
Frederick,
to your first point, they'll need to agree on some set of
algorithms to get interoperability for widgets, as a platform.
Regards,
--
Thomas Roessler, W3C <[EMAIL PROTECTED]>
On 25 Sep 2008, at 15:52, Frederick Hirsch wrote:
one question I have is the following:
XML Signature makes an effort to allow the specification of
algorithm with the data, thus allowing it to be self-specifying
and modifiable. Why do you feel a requirement to limit to a
single algorithm? What happens if you select RSA-SHA256 and then
a need is seen for SHA-512 or an alternative to RSA due to some
new attack or weakness?
Why not leverage the flexibility of XML Signature to allow
different algorithms, along lines of Receiver MUST support RSA-
SHA1, RSA-SHA256 "or better" and Sender MUST support RSA-SHA256
etc But perhaps I am anticipating WG discussion.
Draft looks good, maybe
s/Anyhow, d/D/
#2 s/do/should
Perhaps add #4, is there sense is supporting more than one
algorithm?
regards, Frederick
Frederick Hirsch
Nokia
On Sep 25, 2008, at 9:44 AM, Arthur Barstow wrote:
Below is my DRAFT e-mail to the XML Sec WG regarding Issue #22.
Is this OK? If not, please send suggested changes that will make
it OK.
FYI, I discussed this impending e-mail with Frederick and he was
agreeable to me including him on this Draft email.
-Thanks, Art
=== START DRAFT
To: [EMAIL PROTECTED]
Cc: public-webapps@w3.org
Subject: Seeking feedback regarding Widgets Digital Signatures
spec
Frederick, All,
As you may know, the Web Applications WG [WebApps] is working on
a Digital Signature specification for "Widgets" (see [Widgets]
for a definition of Widget in this context).
The FPWD of our Digital Signature spec is at [DigSig-TR] and the
latest Editor's Draft is available at [DigSig-ED].
Anyhow, during our August f2f meeting, we discussed what we call
Issue #22 - "Is sha1 as a DigestMethod strong enough for Widgets
digital signatures?" [Issue-22]. At then end of this discussion
[Issue-22-Discuss] I agreed to the following action:
[[
Ask the XML Sec WG "what algorithm do you recommend we use and
what identifier should we use for it?
]]
Our questions are:
1. What (if any) issues do you foresee if we require support for
SHA-256 (rather than SHA-1)?
2. What algorithm do we use?
3. What identifier do we use for the algorithm?
-Regards, Art Barstow
Co-Chair of the WebApps WG
[WebApps] <http://www.w3.org/2008/webapps/wiki/Main_Page>
[Widgets] <http://www.w3.org/TR/widgets-reqs/#introduction>
[DigSig-TR] <http://www.w3.org/TR/widgets-digsig/>
[DigSig-ED] <http://dev.w3.org/2006/waf/widgets-digsig/>
[Issue-22] <http://www.w3.org/2008/webapps/track/issues/22>
[Issue-22-Discuss] <http://www.w3.org/2008/08/27-wam-minutes.html#item07
>
Begin forwarded message:
From: Frederick Hirsch <[EMAIL PROTECTED]>
Date: 25 September 2008 16:03:27 CEDT
To: "ext Thomas Roessler" <[EMAIL PROTECTED]>
Cc: Arthur Barstow <[EMAIL PROTECTED]>, Marcos Caceres <[EMAIL PROTECTED]
>, Mark Priestley <[EMAIL PROTECTED]>, Arve Bersvendsen <[EMAIL PROTECTED]
>
Subject: Re: DRAFT: Seeking feedback regarding Widgets Digital
Signatures spec
indeed, but the SHA-1 risk is not the last risk we will ever see...
regards, Frederick
Frederick Hirsch
Nokia
On Sep 25, 2008, at 9:56 AM, ext Thomas Roessler wrote:
Frederick,
to your first point, they'll need to agree on some set of
algorithms to get interoperability for widgets, as a platform.
Regards,
--
Thomas Roessler, W3C <[EMAIL PROTECTED]>
On 25 Sep 2008, at 15:52, Frederick Hirsch wrote:
one question I have is the following:
XML Signature makes an effort to allow the specification of
algorithm with the data, thus allowing it to be self-specifying
and modifiable. Why do you feel a requirement to limit to a single
algorithm? What happens if you select RSA-SHA256 and then a need
is seen for SHA-512 or an alternative to RSA due to some new
attack or weakness?
Why not leverage the flexibility of XML Signature to allow
different algorithms, along lines of Receiver MUST support RSA-
SHA1, RSA-SHA256 "or better" and Sender MUST support RSA-SHA256
etc But perhaps I am anticipating WG discussion.
Draft looks good, maybe
s/Anyhow, d/D/
#2 s/do/should
Perhaps add #4, is there sense is supporting more than one
algorithm?
regards, Frederick
Frederick Hirsch
Nokia
On Sep 25, 2008, at 9:44 AM, Arthur Barstow wrote:
Below is my DRAFT e-mail to the XML Sec WG regarding Issue #22.
Is this OK? If not, please send suggested changes that will make
it OK.
FYI, I discussed this impending e-mail with Frederick and he was
agreeable to me including him on this Draft email.
-Thanks, Art
=== START DRAFT
To: [EMAIL PROTECTED]
Cc: public-webapps@w3.org
Subject: Seeking feedback regarding Widgets Digital Signatures spec
Frederick, All,
As you may know, the Web Applications WG [WebApps] is working on
a Digital Signature specification for "Widgets" (see [Widgets]
for a definition of Widget in this context).
The FPWD of our Digital Signature spec is at [DigSig-TR] and the
latest Editor's Draft is available at [DigSig-ED].
Anyhow, during our August f2f meeting, we discussed what we call
Issue #22 - "Is sha1 as a DigestMethod strong enough for Widgets
digital signatures?" [Issue-22]. At then end of this discussion
[Issue-22-Discuss] I agreed to the following action:
[[
Ask the XML Sec WG "what algorithm do you recommend we use and
what identifier should we use for it?
]]
Our questions are:
1. What (if any) issues do you foresee if we require support for
SHA-256 (rather than SHA-1)?
2. What algorithm do we use?
3. What identifier do we use for the algorithm?
-Regards, Art Barstow
Co-Chair of the WebApps WG
[WebApps] <http://www.w3.org/2008/webapps/wiki/Main_Page>
[Widgets] <http://www.w3.org/TR/widgets-reqs/#introduction>
[DigSig-TR] <http://www.w3.org/TR/widgets-digsig/>
[DigSig-ED] <http://dev.w3.org/2006/waf/widgets-digsig/>
[Issue-22] <http://www.w3.org/2008/webapps/track/issues/22>
[Issue-22-Discuss] <http://www.w3.org/2008/08/27-wam-minutes.html#item07
>
Begin forwarded message:
From: Thomas Roessler <[EMAIL PROTECTED]>
Date: 25 September 2008 15:56:53 CEDT
To: Frederick Hirsch <[EMAIL PROTECTED]>
Cc: Arthur Barstow <[EMAIL PROTECTED]>, Marcos Caceres <[EMAIL PROTECTED]
>, Mark Priestley <[EMAIL PROTECTED]>, Arve Bersvendsen <[EMAIL PROTECTED]
>
Subject: Re: DRAFT: Seeking feedback regarding Widgets Digital
Signatures spec
Frederick,
to your first point, they'll need to agree on some set of algorithms
to get interoperability for widgets, as a platform.
Regards,
--
Thomas Roessler, W3C <[EMAIL PROTECTED]>
On 25 Sep 2008, at 15:52, Frederick Hirsch wrote:
one question I have is the following:
XML Signature makes an effort to allow the specification of
algorithm with the data, thus allowing it to be self-specifying and
modifiable. Why do you feel a requirement to limit to a single
algorithm? What happens if you select RSA-SHA256 and then a need is
seen for SHA-512 or an alternative to RSA due to some new attack or
weakness?
Why not leverage the flexibility of XML Signature to allow
different algorithms, along lines of Receiver MUST support RSA-
SHA1, RSA-SHA256 "or better" and Sender MUST support RSA-SHA256 etc
But perhaps I am anticipating WG discussion.
Draft looks good, maybe
s/Anyhow, d/D/
#2 s/do/should
Perhaps add #4, is there sense is supporting more than one algorithm?
regards, Frederick
Frederick Hirsch
Nokia
On Sep 25, 2008, at 9:44 AM, Arthur Barstow wrote:
Below is my DRAFT e-mail to the XML Sec WG regarding Issue #22.
Is this OK? If not, please send suggested changes that will make
it OK.
FYI, I discussed this impending e-mail with Frederick and he was
agreeable to me including him on this Draft email.
-Thanks, Art
=== START DRAFT
To: [EMAIL PROTECTED]
Cc: public-webapps@w3.org
Subject: Seeking feedback regarding Widgets Digital Signatures spec
Frederick, All,
As you may know, the Web Applications WG [WebApps] is working on a
Digital Signature specification for "Widgets" (see [Widgets] for a
definition of Widget in this context).
The FPWD of our Digital Signature spec is at [DigSig-TR] and the
latest Editor's Draft is available at [DigSig-ED].
Anyhow, during our August f2f meeting, we discussed what we call
Issue #22 - "Is sha1 as a DigestMethod strong enough for Widgets
digital signatures?" [Issue-22]. At then end of this discussion
[Issue-22-Discuss] I agreed to the following action:
[[
Ask the XML Sec WG "what algorithm do you recommend we use and
what identifier should we use for it?
]]
Our questions are:
1. What (if any) issues do you foresee if we require support for
SHA-256 (rather than SHA-1)?
2. What algorithm do we use?
3. What identifier do we use for the algorithm?
-Regards, Art Barstow
Co-Chair of the WebApps WG
[WebApps] <http://www.w3.org/2008/webapps/wiki/Main_Page>
[Widgets] <http://www.w3.org/TR/widgets-reqs/#introduction>
[DigSig-TR] <http://www.w3.org/TR/widgets-digsig/>
[DigSig-ED] <http://dev.w3.org/2006/waf/widgets-digsig/>
[Issue-22] <http://www.w3.org/2008/webapps/track/issues/22>
[Issue-22-Discuss] <http://www.w3.org/2008/08/27-wam-minutes.html#item07
>
Begin forwarded message:
From: "Marcos Caceres" <[EMAIL PROTECTED]>
Date: 25 September 2008 15:53:38 CEDT
To: "Arthur Barstow" <[EMAIL PROTECTED]>
Cc: "Thomas Roessler" <[EMAIL PROTECTED]>, "Mark Priestley" <[EMAIL PROTECTED]
>, "Arve Bersvendsen" <[EMAIL PROTECTED]>, "Frederick Hirsch" <[EMAIL PROTECTED]
>
Subject: Re: DRAFT: Seeking feedback regarding Widgets Digital
Signatures spec
Sounds fine to me too.
On Thu, Sep 25, 2008 at 2:44 PM, Arthur Barstow
<[EMAIL PROTECTED]> wrote:
Below is my DRAFT e-mail to the XML Sec WG regarding Issue #22.
Is this OK? If not, please send suggested changes that will make it
OK.
FYI, I discussed this impending e-mail with Frederick and he was
agreeable
to me including him on this Draft email.
-Thanks, Art
=== START DRAFT
To: [EMAIL PROTECTED]
Cc: public-webapps@w3.org
Subject: Seeking feedback regarding Widgets Digital Signatures spec
Frederick, All,
As you may know, the Web Applications WG [WebApps] is working on a
Digital
Signature specification for "Widgets" (see [Widgets] for a
definition of
Widget in this context).
The FPWD of our Digital Signature spec is at [DigSig-TR] and the
latest
Editor's Draft is available at [DigSig-ED].
Anyhow, during our August f2f meeting, we discussed what we call
Issue #22 -
"Is sha1 as a DigestMethod strong enough for Widgets digital
signatures?"
[Issue-22]. At then end of this discussion [Issue-22-Discuss] I
agreed to
the following action:
[[
Ask the XML Sec WG "what algorithm do you recommend we use and what
identifier should we use for it?
]]
Our questions are:
1. What (if any) issues do you foresee if we require support for
SHA-256
(rather than SHA-1)?
2. What algorithm do we use?
3. What identifier do we use for the algorithm?
-Regards, Art Barstow
Co-Chair of the WebApps WG
[WebApps] <http://www.w3.org/2008/webapps/wiki/Main_Page>
[Widgets] <http://www.w3.org/TR/widgets-reqs/#introduction>
[DigSig-TR] <http://www.w3.org/TR/widgets-digsig/>
[DigSig-ED] <http://dev.w3.org/2006/waf/widgets-digsig/>
[Issue-22] <http://www.w3.org/2008/webapps/track/issues/22>
[Issue-22-Discuss] <http://www.w3.org/2008/08/27-wam-minutes.html#item07
>
--
Marcos Caceres
http://datadriven.com.au
Begin forwarded message:
From: Frederick Hirsch <[EMAIL PROTECTED]>
Date: 25 September 2008 15:52:41 CEDT
To: Arthur Barstow <[EMAIL PROTECTED]>
Cc: Marcos Caceres <[EMAIL PROTECTED]>, Thomas Roessler
<[EMAIL PROTECTED]>, Mark Priestley <[EMAIL PROTECTED]>, Arve
Bersvendsen <[EMAIL PROTECTED]>
Subject: Re: DRAFT: Seeking feedback regarding Widgets Digital
Signatures spec
one question I have is the following:
XML Signature makes an effort to allow the specification of
algorithm with the data, thus allowing it to be self-specifying and
modifiable. Why do you feel a requirement to limit to a single
algorithm? What happens if you select RSA-SHA256 and then a need is
seen for SHA-512 or an alternative to RSA due to some new attack or
weakness?
Why not leverage the flexibility of XML Signature to allow different
algorithms, along lines of Receiver MUST support RSA-SHA1, RSA-
SHA256 "or better" and Sender MUST support RSA-SHA256 etc But
perhaps I am anticipating WG discussion.
Draft looks good, maybe
s/Anyhow, d/D/
#2 s/do/should
Perhaps add #4, is there sense is supporting more than one algorithm?
regards, Frederick
Frederick Hirsch
Nokia
On Sep 25, 2008, at 9:44 AM, Arthur Barstow wrote:
Below is my DRAFT e-mail to the XML Sec WG regarding Issue #22.
Is this OK? If not, please send suggested changes that will make it
OK.
FYI, I discussed this impending e-mail with Frederick and he was
agreeable to me including him on this Draft email.
-Thanks, Art
=== START DRAFT
To: [EMAIL PROTECTED]
Cc: public-webapps@w3.org
Subject: Seeking feedback regarding Widgets Digital Signatures spec
Frederick, All,
As you may know, the Web Applications WG [WebApps] is working on a
Digital Signature specification for "Widgets" (see [Widgets] for a
definition of Widget in this context).
The FPWD of our Digital Signature spec is at [DigSig-TR] and the
latest Editor's Draft is available at [DigSig-ED].
Anyhow, during our August f2f meeting, we discussed what we call
Issue #22 - "Is sha1 as a DigestMethod strong enough for Widgets
digital signatures?" [Issue-22]. At then end of this discussion
[Issue-22-Discuss] I agreed to the following action:
[[
Ask the XML Sec WG "what algorithm do you recommend we use and what
identifier should we use for it?
]]
Our questions are:
1. What (if any) issues do you foresee if we require support for
SHA-256 (rather than SHA-1)?
2. What algorithm do we use?
3. What identifier do we use for the algorithm?
-Regards, Art Barstow
Co-Chair of the WebApps WG
[WebApps] <http://www.w3.org/2008/webapps/wiki/Main_Page>
[Widgets] <http://www.w3.org/TR/widgets-reqs/#introduction>
[DigSig-TR] <http://www.w3.org/TR/widgets-digsig/>
[DigSig-ED] <http://dev.w3.org/2006/waf/widgets-digsig/>
[Issue-22] <http://www.w3.org/2008/webapps/track/issues/22>
[Issue-22-Discuss] <http://www.w3.org/2008/08/27-wam-minutes.html#item07
>
Begin forwarded message:
From: Thomas Roessler <[EMAIL PROTECTED]>
Date: 25 September 2008 15:52:02 CEDT
To: Arthur Barstow <[EMAIL PROTECTED]>
Cc: Marcos Caceres <[EMAIL PROTECTED]>, Mark Priestley <[EMAIL PROTECTED]
>, Arve Bersvendsen <[EMAIL PROTECTED]>, Frederick Hirsch <[EMAIL PROTECTED]
>
Subject: Re: DRAFT: Seeking feedback regarding Widgets Digital
Signatures spec
fine with me
-- Thomas Roessler, W3C <[EMAIL PROTECTED]>
On 25 Sep 2008, at 15:44, Arthur Barstow wrote:
Below is my DRAFT e-mail to the XML Sec WG regarding Issue #22.
Is this OK? If not, please send suggested changes that will make it
OK.
FYI, I discussed this impending e-mail with Frederick and he was
agreeable to me including him on this Draft email.
-Thanks, Art
=== START DRAFT
To: [EMAIL PROTECTED]
Cc: public-webapps@w3.org
Subject: Seeking feedback regarding Widgets Digital Signatures spec
Frederick, All,
As you may know, the Web Applications WG [WebApps] is working on a
Digital Signature specification for "Widgets" (see [Widgets] for a
definition of Widget in this context).
The FPWD of our Digital Signature spec is at [DigSig-TR] and the
latest Editor's Draft is available at [DigSig-ED].
Anyhow, during our August f2f meeting, we discussed what we call
Issue #22 - "Is sha1 as a DigestMethod strong enough for Widgets
digital signatures?" [Issue-22]. At then end of this discussion
[Issue-22-Discuss] I agreed to the following action:
[[
Ask the XML Sec WG "what algorithm do you recommend we use and what
identifier should we use for it?
]]
Our questions are:
1. What (if any) issues do you foresee if we require support for
SHA-256 (rather than SHA-1)?
2. What algorithm do we use?
3. What identifier do we use for the algorithm?
-Regards, Art Barstow
Co-Chair of the WebApps WG
[WebApps] <http://www.w3.org/2008/webapps/wiki/Main_Page>
[Widgets] <http://www.w3.org/TR/widgets-reqs/#introduction>
[DigSig-TR] <http://www.w3.org/TR/widgets-digsig/>
[DigSig-ED] <http://dev.w3.org/2006/waf/widgets-digsig/>
[Issue-22] <http://www.w3.org/2008/webapps/track/issues/22>
[Issue-22-Discuss] <http://www.w3.org/2008/08/27-wam-minutes.html#item07
>
Begin forwarded message:
From: Arthur Barstow <[EMAIL PROTECTED]>
Date: 25 September 2008 15:44:07 CEDT
To: Marcos Caceres <[EMAIL PROTECTED]>, Thomas Roessler
<[EMAIL PROTECTED]>, Mark Priestley <[EMAIL PROTECTED]>, Arve
Bersvendsen <[EMAIL PROTECTED]>
Cc: Frederick Hirsch <[EMAIL PROTECTED]>
Subject: DRAFT: Seeking feedback regarding Widgets Digital
Signatures spec
Below is my DRAFT e-mail to the XML Sec WG regarding Issue #22.
Is this OK? If not, please send suggested changes that will make it
OK.
FYI, I discussed this impending e-mail with Frederick and he was
agreeable to me including him on this Draft email.
-Thanks, Art
=== START DRAFT
To: [EMAIL PROTECTED]
Cc: public-webapps@w3.org
Subject: Seeking feedback regarding Widgets Digital Signatures spec
Frederick, All,
As you may know, the Web Applications WG [WebApps] is working on a
Digital Signature specification for "Widgets" (see [Widgets] for a
definition of Widget in this context).
The FPWD of our Digital Signature spec is at [DigSig-TR] and the
latest Editor's Draft is available at [DigSig-ED].
Anyhow, during our August f2f meeting, we discussed what we call
Issue #22 - "Is sha1 as a DigestMethod strong enough for Widgets
digital signatures?" [Issue-22]. At then end of this discussion
[Issue-22-Discuss] I agreed to the following action:
[[
Ask the XML Sec WG "what algorithm do you recommend we use and what
identifier should we use for it?
]]
Our questions are:
1. What (if any) issues do you foresee if we require support for
SHA-256 (rather than SHA-1)?
2. What algorithm do we use?
3. What identifier do we use for the algorithm?
-Regards, Art Barstow
Co-Chair of the WebApps WG
[WebApps] <http://www.w3.org/2008/webapps/wiki/Main_Page>
[Widgets] <http://www.w3.org/TR/widgets-reqs/#introduction>
[DigSig-TR] <http://www.w3.org/TR/widgets-digsig/>
[DigSig-ED] <http://dev.w3.org/2006/waf/widgets-digsig/>
[Issue-22] <http://www.w3.org/2008/webapps/track/issues/22>
[Issue-22-Discuss] <http://www.w3.org/2008/08/27-wam-minutes.html#item07
>
