Subject: RE: I-D ACTION:draft-ietf-pkix-logotypes-02.txt

From: Stefan Santesson <[email-masked]>
Date: Thu, 02 May 2002 12:18:48 +0200

Peter,

Was 300x200 a serious suggestion or a joke?

Further comments in line.

At 16:30 2002-04-21 +1200, Peter Gutmann wrote:

>"Housley, Russ" <[email-masked]> writes:
>
> >At 03:30 PM 4/19/2002 +1200, Peter Gutmann wrote:
> >>"Housley, Russ" <[email-masked]> writes:
> >>
> >>>What maximum size do you suggest?
> >>
> >>I would say 320x200 *minimum*, for the MPEGs :-).
> >
> >We have not allowed MPEGs, just static images in JPEG or GIF format.
>
>Actually that was a dual-purpose comment, firstly to reference Bob Jueneman's
>joke about putting MPEGs in the DN, and secondly to point out that setting
>arbitrary limits on image sizes is probably pointless given that companies are
>going to use whatever size and format they feel like, no matter what the spec
>says.

I see your point, but I still believe that there are a valid need in this case.

I assume that some GUI's for certificate display will need to know and 
design size properties of a certificate display window. This means that the 
GUI makers have to define size limits for all sorts of things such as text 
fields, logos, etc. If no standard sizes are available they must invent 
their own.
A standard logotype max-size definition thus gives both the GUI makes and 
the CA's a hint about what they should expect and produce in order to get 
optimal performance.

If a CA oversize their logos it doesn't have to mean that their 
certificates are rejected, but the CA may have to accept the fact that 
their attached logos are distorted through down sizing into the GUI's 
maximum display size.

I can't imagine that we will see scroll bars on logotypes (as in text 
windows) :-)

>Can you imagine KPMGCoopersPriceLybrandWaterhouseAnderson distributing a
>single cert without the Official Corporate Logo(tm) with Official Corporate
>Animation(tm) and Official Corporate Song(tm) playing in the background?.

In fact I can, if almost nobody is able to even see the darn thing thanks 
to this feature :-)

Jokes aside. I agree that some of these aspects has to be settled by the 
market players, but I still believe GUI implementers need some limitations 
on what they have to handle.

>You only need to look at the cert policy text size limit set in RFC 2459 as an
>example.  I used to check the size limit given in the RFC, but after finding
>the first dozen or so CAs who went way over the limit (some texts were five
>times the size allowed by the RFC) I changed my code to use 5x the max size as
>the upper limit.  After still getting complaints that certs were being
>rejected, I removed the check altogether, since no-one seems to pay any
>attention to the size limits.  So I think that while a comment that N x M is a
>good upper limit would be useful, you'd have to accept that it's going to be
>ignored by anyone who feels their Corporate Image would be slighted by such a
>constraint (or, more likely, who doesn't bother to read RFCs).

I see your point. But I think the case is different for logos since they 
can be scaled but not scrolled. See comment above.

/Stefan

>Peter.

---

From: Simon Josefsson <[email-masked]>
Date: Thu, 02 May 2002 13:43:13 +0200

Stefan Santesson <[email-masked]> writes:

> design size properties of a certificate display window. This means
> that the GUI makers have to define size limits for all sorts of things
> such as text fields, logos, etc. If no standard sizes are available
> they must invent their own.
> A standard logotype max-size definition thus gives both the GUI makes
> and the CA's a hint about what they should expect and produce in order
> to get optimal performance.

Has the SVG format [1] been considered?  It seems to me that it has
some advantages:

* No need to define size limits to 320x200 or whatever. Devices render
  the image using the resolution of its own screen.

* Disability; (color) blindness, etc.  To point of PKIX logotypes seem
  to move closer to human behaviour, and human behaviour includes
  various form of disabilities as well.

* Smaller size?  I haven't measured, but I can imagine that some logos
  can be described more compactly using a text langugage.

...and to bost...

* Logos will look _better_ since the device renders the image on the
  screen using its special characteristics, instead of having to
  resize, scale or translate the image into monochrome. (The latter
  can really destroy logos if the algorithm to translate the image
  into monochrome is poor, as can be expected on limited devices.)

[1] http://www.w3.org/Graphics/SVG/