Internet Engineering Task Force (IETF)                         S. Turner
Request for Comments: 5917                                          IECA
Category: Informational                                        June 2010
ISSN: 2070-1721


                     Clearance Sponsor Attribute

Abstract

  This document defines the clearance sponsor attribute.  It indicates
  the entity that sponsored (i.e., granted) the clearance.  This
  attribute is intended for use in public key certificates and
  attribute certificates that also include the clearance attribute.

Status of This Memo

  This document is not an Internet Standards Track specification; it is
  published for informational purposes.

  This document is a product of the Internet Engineering Task Force
  (IETF).  It represents the consensus of the IETF community.  It has
  received public review and has been approved for publication by the
  Internet Engineering Steering Group (IESG).  Not all documents
  approved by the IESG are a candidate for any level of Internet
  Standard; see Section 2 of RFC 5741.

  Information about the current status of this document, any
  errata, and how to provide feedback on it may be obtained at
  http://www.rfc-editor.org/info/rfc5917.

Copyright Notice

  Copyright (c) 2010 IETF Trust and the persons identified as the
  document authors.  All rights reserved.

  This document is subject to BCP 78 and the IETF Trust's Legal
  Provisions Relating to IETF Documents
  (http://trustee.ietf.org/license-info) in effect on the date of
  publication of this document.  Please review these documents
  carefully, as they describe your rights and restrictions with respect
  to this document.  Code Components extracted from this document must
  include Simplified BSD License text as described in Section 4.e of
  the Trust Legal Provisions and are provided without warranty as
  described in the Simplified BSD License.






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RFC 5917               Clearance Sponsor Attribute             June 2010


1.  Introduction

  This document specifies the clearance sponsor attribute.  It is
  included in public key certificates [RFC5280] and attribute
  certificates [RFC5755].  This attribute is only meaningful as a
  companion of the clearance attribute [RFC5755] [RFC5912].  The
  clearance sponsor is the entity (e.g., agency, department, or
  organization) that granted the clearance to the subject named in the
  certificate.  For example, the clearance sponsor for a subject
  asserting the Amoco clearance values [RFC3114] could be
  "Engineering".

  This attribute may be used in automated authorization decisions.  For
  example, a web server deciding whether to allow a user access could
  check that the clearance sponsor present in the user's certificate is
  on an "approved" list.  This check is performed in addition to
  certification path validation [RFC5280].  The mechanism for managing
  the "approved" list is beyond the scope of this document.

  NOTE: This document does not provide an equivalent Lightweight
  Directory Access Protocol (LDAP) schema specification as this
  attribute is initially targeted at public key certificates [RFC5280]
  and attribute certificates [RFC5755].  Definition of an equivalent
  LDAP schema is left to a future specification.

1.1.  Terminology

  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].

1.2.  ASN.1 Syntax Notation

  The attribute is defined using ASN.1 [X.680], [X.681], [X.682], and
  [X.683].

2.  Clearance Sponsor

  The clearance sponsor attribute, which is only meaningful if the
  clearance attribute [RFC5755] [RFC5912] is also present, indicates
  the sponsor of the clearance of the subject with which this attribute
  is associated.  The clearance sponsor attribute is a DirectoryString
  [RFC5280], which MUST use the UTF8String CHOICE, with a minimum size
  of 1 character and a maximum of 64 characters.







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  The following object identifier identifies the sponsor attribute:

  id-clearanceSponsor OBJECT IDENTIFIER ::= {
    joint-iso-ccitt(2) country(16) us(840) organization(1) gov(101)
    dod(2) infosec(1) attributes(5) 68
  }

  The ASN.1 syntax for the clearance sponsor attribute is as follows:

  at-clearanceSponsor ATTRIBUTE ::= {
    TYPE                   DirectoryString { ub-clearance-sponsor }
                           ( WITH COMPONENTS { utf8String PRESENT } )
    EQUALITY MATCHING RULE caseIgnoreMatch
    IDENTIFIED BY          id-clearanceSponsor
  }

  ub-clearance-sponsor INTEGER ::= 64

  There MUST only be one value of clearanceSponsor associated with a
  particular certificate.  Distinct sponsors MUST be represented in
  separate certificates.

  When an environment uses the Clearance Sponsor attribute, it is
  important that the same representation of the sponsor be used
  throughout the environment (e.g., using the same acronym).  Further,
  the value in this attribute is not meant to be globally unique.  When
  included in certificates, it is unique within the scope of the
  issuer.

3.  Security Considerations

  If this attribute is used as part of an authorization process, the
  procedures employed by the entity that assigns each clearance sponsor
  value must ensure that the correct value is applied.  Including this
  attribute in a public key certificate or attribute certificate
  ensures that the value for the clearance sponsor is integrity
  protected.

  The certificate issuer and clearance sponsor are not necessarily the
  same entity.  If they are separate entities, then the mechanism used
  by the clearance sponsor to convey to the certificate issuer that the
  clearance sponsor did in fact grant the clearance to the subject
  needs to be protected from unauthorized modification.

  If two entities are verifying each other's certificates, they do not
  share the same issuer, and they use the same clearance sponsor value
  (e.g., a United Kingdom PKI includes "MoD" and a New Zealand PKI also
  includes "MoD"), then the relying party has two choices: 1) accept



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  the two strings as equivalent, or 2) indicate the sponsor as well as
  the trust anchor.  To solve this problem, a mechanism, which is
  outside the scope of this specification, could be developed to allow
  a relying party to group together issuers that share a same context
  within which sponsor names have a unique significance.

  While values of DirectoryString can include the NUL (U+0000) code
  point, values used to represent clearance sponsors typically would
  not.  Implementations of the caseIgnoreMatch rule must, per X.501,
  consider all of the assertion value and attribute value in matching
  and hence protect against truncation attacks.

4.  References

4.1.  Normative References

  [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

  [RFC5280]  Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
             Housley, R., and W. Polk, "Internet X.509 Public Key
             Infrastructure Certificate and Certificate Revocation List
             (CRL) Profile", RFC 5280, May 2008.

  [RFC5755]  Farrell, S., Housley, R., and S. Turner, "An Internet
             Attribute Certificate Profile for Authorization", RFC
             5755, January 2010.

  [RFC5912]  Schaad, J. and P. Hoffman, "New ASN.1 Modules for the
             Public Key Infrastructure Using X.509 (PKIX)", RFC 5912,
             June 2010.

  [X.520]    ITU-T Recommendation X.520 (2002) | ISO/IEC 9594-6:2002,
             Information technology - The Directory:Selected Attribute
             Types.

  [X.680]    ITU-T Recommendation X.680 (2002) | ISO/IEC 8824-1:2002,
             Information technology - Abstract Syntax Notation One
             (ASN.1): Specification of basic notation.

  [X.681]    ITU-T Recommendation X.681 (2002) | ISO/IEC 8824-2:2002,
             Information Technology - Abstract Syntax Notation One:
             Information Object Specification.

  [X.682]    ITU-T Recommendation X.682 (2002) | ISO/IEC 8824-3:2002,
             Information Technology - Abstract Syntax Notation One:
             Constraint Specification.




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  [X.683]    ITU-T Recommendation X.683 (2002) | ISO/IEC 8824-4:2002,
             Information Technology - Abstract Syntax Notation One:
             Parameterization of ASN.1 Specifications.

4.2.  Informative References

  [RFC3114]  Nicolls, W., "Implementing Company Classification Policy
             with the S/MIME Security Label", RFC 3114, May 2002.











































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Appendix A.  ASN.1 Module

  This appendix provides the normative ASN.1 [X.680] definitions for
  the structures described in this specification using ASN.1 as defined
  in [X.680], [X.681], [X.682], and [X.683].

  ClearanceSponsorAttribute-2008
    { joint-iso-ccitt(2) country(16) us(840) organization(1) gov(101)
      dod(2) infosec(1) modules(0)
      id-clearanceSponsorAttribute-2008(35) }

  DEFINITIONS IMPLICIT TAGS ::=

  BEGIN

  -- EXPORTS ALL --

  IMPORTS

  -- Imports from New PKIX ASN.1 [RFC5912]

    DirectoryString
      PKIX1Explicit-2009
        { iso(1) identified-organization(3) dod(6) internet(1)
          security(5) mechanisms(5) pkix(7) id-mod(0)
          id-pkix1-explicit-02(51) }

  -- Imports from New PKIX ASN.1 [RFC5912]

    ATTRIBUTE
      FROM PKIX-CommonTypes-2009
        { iso(1) identified-organization(3) dod(6) internet(1)
          security(5) mechanisms(5) pkix(7) id-mod(0)
          id-mod-pkixCommon-02(57) }

  -- Imports from ITU-T X.520 [X.520]

    caseIgnoreMatch
      FROM SelectedAttributeTypes
        { joint-iso-itu-t ds(5) module(1) selectedAttributeTypes(5) 4 }

  ;

  -- sponsor attribute OID and syntax

  id-clearanceSponsor OBJECT IDENTIFIER ::= {
    joint-iso-ccitt(2) country(16) us(840) organization(1) gov(101)
    dod(2) infosec(1) attributes(5) 68



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  }

  at-clearanceSponsor ATTRIBUTE ::= {
    TYPE                   DirectoryString { ub-clearance-sponsor }
                           ( WITH COMPONENTS { utf8String PRESENT } )
    EQUALITY MATCHING RULE caseIgnoreMatch
    IDENTIFIED BY          id-clearanceSponsor
  }

  ub-clearance-sponsor INTEGER ::= 64

  END

Author's Address

  Sean Turner
  IECA, Inc.
  3057 Nutley Street, Suite 106
  Fairfax, VA 22031
  USA

  EMail: [email protected]





























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