Subject: Scent logotypes minor update

From: [email-masked] (Peter Gutmann)
Date: Fri, 27 Sep 2002 17:14:31 +1200 (NZST)

I got quite a bit of feedback on this, attached below is a revised version
with improvements suggested by various people (you know who you are :-).

(Incidentally, I do know what irony is: It's like goldy and silvery, only
 cheaper).

-- Snip --

First, Bob Jueneman suggested MPEGs in certificates as a joke.  This is now
being standardised in the logotypes draft.

Then I suggested theme music in certificates as a joke.  This is now being
standardised in the logotypes draft.

Now, in an attempt to make the discussion even more surreal, I give you...

4.3. Scent logotypes

Alongside audio and video logotypes, it may be desirable for certificates to
carry scent logotypes in order to uniquely brand certificate holders in a
manner meaningful to relying parties.  For example, McDonalds may choose to
imbue their certificates with the aroma of fried beef patties and grilled
cheese, the National Park Service may choose the essence of pure Colorado
mountain air with just a hint of pine, the NRA would use a heady mixture of
cordite and gun oil, and PKIX could use cold coffee and stale cigarette smoke.

The new logotype would be implemented in the form of scratch-n-sniff
certificates, and will assist relying parties in making informed decisions as
to whether a particular certificate is trustworthy and relevant for its
intended usage.  Service providers and product vendors invest a lot of money
and resources into creating a strong relation between positive user
experiences and easily recognizable scents such as grilled beef, fresh air,
and cordite, allowing easy and familiar branding of certificates.

The scent logotype extension MUST have the following syntax:

      LogotypeScent ::= SEQUENCE {
         scentSubtype     IA5String, -- MIME scent subtype
         scent            OCTET STRING,
         refreshInfo      ScentRefreshInfo OPTIONAL
         }
      
A MIME type is used to specify the format of the file containing the scent
logotype data.  The scent element contains the scratch-n-sniff scent logotype
associated with the certificate.

Since scents fade over time, it may be necessary to periodically refresh the
scent to preserve the user experience:

      ScentRefreshInfo ::= SEQUENCE {
         refreshTime      INTEGER DEFAULT 30,
         refreshCount [0] INTEGER DEFAULT 1,
         refreshUrl       IA5String,
         refreshUrlHash   OCTET STRING OPTIONAL }

The refresh time specifies the time in seconds after which the scent must be
refreshed, the refresh count specifies the number of times the scent should be
refreshed after initial deployment, and the URL and optional hash of the data
stored at the URL location contains the scent payload and integrity protection
mechanism.

7.1. Security considerations

Implementors should be aware that there exists the potential for confusion
among relying parties when evaluating similar scent logotypes.  For example,
relying parties may not be able to meaningfully differentiate between the
logos for McDonalds and Burger King, or Hersheys and Nestle, or Sealord and
Penthouse.  Resolution of this issue lies outside the scope of this memo.

Intensive usage of scent logotypes may trigger smoke alarms and, by extension,
sprinkler systems.  Users should be aware of this and carry an umbrella.

Certificate users involved in skunkworks projects are discouraged from adding
scent logotypes to their certificates.