This public working draft is being issued in order to keep the public
informed about P3P. However, there are a number of areas where the
working group is well aware that further work is needed. These open
issues are summarized here. W3C members may also consult the P3P open
issues list for more details.
Platform for Privacy Preferences (P3P) Status Notes
26 August 1999
This document was prepared by Lorrie Cranor
(firstname.lastname@example.org) on behalf of the P3P Specification
Working Group. It is an annex to the 26 August 1999 P3P public
Copyright © 1999 W3C
Keio), All Rights Reserved. W3C
licensing rules apply.
Questions have been raised about how relationships with credit card
companies are reflected in the P3P vocabulary. This and other
vocabulary-specific questions need to be examined by the P3P Policy
and Outreach Working Group.
Base Data Set Issues
Most of the base data set issues have been resolved in the current
draft. Known issues that remain include:
- Need to better document base data set extension mechanism and
discuss a few remaining open questions.
- Need to split date type into two sub-types for date and time.
Most of the internationalization issues have been resolved in
the current draft. We may add a mechanism that will allow multiple
copies of an element to be returned in different languages with the
appropriate language attributes.
RDF/XML Syntax Issues
A number of syntax issues have been raised. We need to either fix the
RDF syntax or agree to use XML syntax without RDF. Once we solve
this problem, we still need to work on a DTD and resolve a number
of minor issues. Major syntax changes are still possible at this point.
The protocol itself is now fairly well document, but a few open issues
- Some questions remain about the Limited P3P protocol using the
HTML link tag, including whether a propID is needed with a link tag.
- Questions remain about whether there should be restrictions on
where a proposal may be stored (i.e. does it have to be stored on the
same host or in the same domain as the realm to which it applies?)
- Questions remain about the use of the realm element. It has been
proposed that P3P provide syntax for excluding
sub-directories from realms. It has also been proposed that the realm
element become a header rather than part of the proposal or that it be
- It has been brought to our attention that some servers will not
accept HTTP headers bigger than 4k. This may be a concern when the P3P
data transfer mechanism is used to return data. We may modify the
header syntax to a more compact syntax to address this problem.
- We may also consider removing automatic data transfer
(source=agent) from P3P 1.0.
A general P3P extension mechanism has been proposed. This would
allow extensions not only to data sets, but to all parts of
P3P. This will likely be added to the specification after some
additional work. It is likely that this mechanism will include an
easy way for implementations that don't wish to recognize extensions
to still be compliant.
User Experience Issues
There are a number of issues that impact the P3P user experience. Most
of these issues require input from the P3P Policy and Outreach working
group before they can be addressed.