Internet Draft                                               C. Francis
PKIX Working Group                                             Raytheon
April 2003                                                    D. Pinkas
Expires: October 2003                                              Bull




                    Attribute Certificate Policy extension
                   <draft-ietf-pkix-acpolicies-extn-03.txt>



Status of this memo

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Abstract

This document describes one certificate extension to explicitly
state the Attribute Certificate (AC) policies that apply to a given
Attribute Certificate.

Conventions Used In This Document

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].

1. Introduction

When issuing a PKC, a Certificate Authority (CA) can perform various
levels of verification with regard to the subject identity.  A CA makes
its verification procedures, as well as other operational rules it
abides by, "visible" through a certificate policy, which may be
referenced by a certificate policies extension in the PKC.

The purpose of this document is to define such an extension, but not
the AC policies themselves.


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2. AC Policy Extension Semantics

Attribute Certificates are defined in [RFC3281].

An Attribute Certificate Policy (ACP) is a set of rules that indicates
generic rules for registering, verifying, delivering and revoking the
attributes contained in a particular Attribute Certificate.

It should thus be noticed that an AA does not necessarily support one
single policy. However, for each AC that is delivered it SHALL make
sure that the policy applies to all the attributes that are contained
in it.

An Attribute Certificate Policy may be used by a certificate user to
decide whether or not to trust the attributes contained in a
certificate for a particular purpose.

When a certificate contains an AC policies extension, the extension
MAY, at the option of the certificate issuer, be either critical or
non-critical.

The AC Policies extension MAY be included in an attribute certificate.
Like all X.509 certificate extensions [X.509], the AC policies
extension is defined using ASN.1 [ASN1].

The AC policies extension is identified by id-pe-ac-policies.

     id-pe-ac-policies OBJECT IDENTIFIER ::= { id-pe 15 }

The AC policies extension includes a list of AC policies recognized by
the issuing authority that apply to the attributes included in the
certificate.

AC Policies may be defined by any organization with a need.  Object
identifiers used to identify AC Policies are assigned in accordance
with [ITU-T Rec. X660 | ISO/IEC 9834-1].

The presence of this extension in an attribute certificate indicates
the AC policies for which the attribute certificate is valid.

An application that recognizes this extension and its content SHALL
process the extension regardless of the value of the criticality flag.

If the extension is both flagged non-critical and is not recognized,
then the application MAY ignore it.

If the extension is flagged critical or is recognized, it indicates
that the attributes contained in the certificate SHALL only be used
for the purpose, and in accordance with the rules implied by one of
the indicated AC policies.



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If the extension is marked critical or is recognized, certificate
users MUST use the list of AC policies to determine whether it is
appropriate to use the attributes contained in that certificate for
a particular transaction.

2.1 AC Policy Extension Syntax

The syntax for the AC Policy extension is:

ac-policies EXTENSION ::= {
     SYNTAX              ac-policiesSyntax
     IDENTIFIED BY       id-pe-ac-policies}

ac-policiesSyntax ::= SEQUENCE SIZE (1..MAX) OF PolicyInformation

PolicyInformation ::= SEQUENCE {
      policyIdentifier      AcPolicyId,
      policyQualifiers      SEQUENCE SIZE (1..MAX) OF
                                     PolicyQualifierInfo OPTIONAL}

AcPolicyId ::= OBJECT IDENTIFIER

   PolicyQualifierInfo ::= SEQUENCE {
        policyQualifierId  PolicyQualifierId,
        qualifier          ANY DEFINED BY policyQualifierId }

To promote interoperability, this document RECOMMENDS that policy
information terms consist of only an OID. When more than one policy
is used, the policy requirements have to be non conflicting, e.g. one
policy may refine the general requirements mandated by another policy.

2.2 Attribute Certificate Policies

The scope of this document is not the definition of the detailed
content of Attribute Certificate policies themselves, therefore
specific policies are not defined in this document.

2.3. Generic Policy Qualifiers

   This specification defines two generic policy qualifier types for
   use by certificate policy writers and certificate issuers, which
   are similar to those used for Certificate Policies in Public Key
   Certificates.  The qualifier types are the CPS Pointer and User
   Notice qualifiers.

   The CPS Pointer qualifier contains a pointer to a Certification
   Practice Statement (CPS) published by the AA.  The pointer is in
   the form of a URI.

   User notice is intended for display to a relying party when a
   certificate is used.  The application software SHOULD display all
   user notices in all certificates of the certification path used,
   except that if a notice is duplicated only one copy need be

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   displayed.  To prevent such duplication, this qualifier SHOULD only
   be present in end-entity certificates.

These policies Qualifiers are defined in [RFC3280].

   -- policyQualifierIds for Internet policy qualifiers

   id-qt          OBJECT IDENTIFIER ::=  { id-pkix 2 }
   id-qt-cps      OBJECT IDENTIFIER ::=  { id-qt 1 }
   id-qt-unotice  OBJECT IDENTIFIER ::=  { id-qt 2 }

3. Security Considerations

The Attribute Certification Policy defined in this document applies
for all the attributes that are included in one AC. AAs shall make sure
that the policy applies to all the attributes which are included in the
certificates they issue.

Attributes may be dynamically grouped in several ACs. It should be
observed that since the management of some attributes may be different,
different policies  may be used by
the same AA.

4. Normative references

[ITU-T Rec. X660 | ITU-T Recommendation Rec X.660 (1992)
ISO/IEC 9834-1]  | ISO/IEC 9834-1: 1993, Information
                   technology - Open Systems Interconnection
                   Procedures for the operation of OSI
                   Registration Authorities: General procedures.

[RFC3280]  Certificate and Certificate Revocation List (CRL) Profile.
           R. Housley, W.Polk, W.Ford, and D. Solo. April 2002.

[RFC3281]  An Internet Attribute Certificate Profile for Authorization.
           S. Farrell S. and R. Housley. April 2002.

[ASN1]    X.680 - X.693 | ISO/IEC 8824: 1-4 Abstract Syntax
          Notation One (ASN.1). See:
          http://www.itu.int/ITU-T/studygroups/com17/languages/ and
          http://asn1.elibel.tm.fr/en/standards/index.htm

[X.509]    ITU-T Recommendation X.509 (2000): Information Technology รป
           Open Systems Interconnections - The Directory:
           Public-key and Attribute Frameworks, March 2000










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Author's Addresses

   Christopher S. Francis
   Raytheon
   1501 72nd Street North, MS 25
   St. Petersburg, Florida  33764
   Email: Chris_S_Francis@Raytheon.com

   Denis Pinkas
   Bull
   Rue Jean Jaures
   78340 Les Clayes-sous-Bois
   FRANCE

   Email: Denis.Pinkas@bull.net


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Acknowledgement

Funding for the RFC Editor function is currently provided by the
Internet Society.






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Annex A (normative): ASN.1 Definitions

ASN.1 Module

PKIXac-policies { iso(1) identified-organization(3) dod(6)
    internet(1) security(5) mechanisms(5) pkix(7) id-mod(0)
    id-mod-ac-policies(26) }

DEFINITIONS IMPLICIT TAGS ::=

BEGIN

-- EXPORTS ALL --

-- IMPORTS --

-- Imports from RFC 3280 [PROFILE], Appendix A.1

      PolicyQualifierId
         FROM PKIX1Explicit88 { iso(1) identified-organization(3)
         dod(6) internet(1) security(5) mechanisms(5) pkix(7)
         mod(0) pkix1-explicit(18) }

-- Arc for private certificate extensions
id-pe OBJECT IDENTIFIER ::= { id-pkix 1}

-- Locally defined OIDs

-- Attributes

     id-pe-ac-policies OBJECT IDENTIFIER ::= { id-pe 15 }

ac-policies EXTENSION ::= {
     SYNTAX              ac-policiesSyntax
     IDENTIFIED BY       id-pe-ac-policies}

ac-policiesSyntax ::= SEQUENCE SIZE (1..MAX) OF PolicyInformation

PolicyInformation ::= SEQUENCE {
      policyIdentifier      acPolicyId,
      policyQualifiers      SEQUENCE SIZE (1..MAX) OF
                            PolicyQualifierInfo OPTIONAL}

acPolicyId ::= OBJECT IDENTIFIER

   PolicyQualifierInfo ::= SEQUENCE {
        policyQualifierId  PolicyQualifierId,
        qualifier          ANY DEFINED BY policyQualifierId }

END





Francis, Pinkas                                                  Page 6