5917
INFORMATIONAL
Clearance Sponsor Attribute
Authors: S. Turner
Date: June 2010
Working Group: NON WORKING GROUP
Stream: IETF
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. This document is not an Internet Standards Track specification; it is published for informational purposes.
RFC 5917
INFORMATIONAL
Errata Exist
Internet Engineering Task Force (IETF) S. Turner
Request for Comments: 5917 IECA
Category: Informational June 2010
ISSN: 2070-1721
<span class="h1">Clearance Sponsor Attribute</span>
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 <a href="./rfc5741#section-2">Section 2 of RFC 5741</a>.
Information about the current status of this document, any
errata, and how to provide feedback on it may be obtained at
<a href="https://www.rfc-editor.org/info/rfc5917">http://www.rfc-editor.org/info/rfc5917</a>.
Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to <a href="https://www.rfc-editor.org/bcp/bcp78">BCP 78</a> and the IETF Trust's Legal
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described in the Simplified BSD License.
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<span class="h2"><a class="selflink" id="section-1" href="#section-1">1</a>. Introduction</span>
This document specifies the clearance sponsor attribute. It is
included in public key certificates [<a href="./rfc5280" title=""Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile"">RFC5280</a>] and attribute
certificates [<a href="./rfc5755" title=""An Internet Attribute Certificate Profile for Authorization"">RFC5755</a>]. This attribute is only meaningful as a
companion of the clearance attribute [<a href="./rfc5755" title=""An Internet Attribute Certificate Profile for Authorization"">RFC5755</a>] [<a href="./rfc5912" title=""New ASN.1 Modules for the Public Key Infrastructure Using X.509 (PKIX)"">RFC5912</a>]. 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 [<a href="./rfc3114" title=""Implementing Company Classification Policy with the S/MIME Security Label"">RFC3114</a>] 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 [<a href="./rfc5280" title=""Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile"">RFC5280</a>]. 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 [<a href="./rfc5280" title=""Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile"">RFC5280</a>]
and attribute certificates [<a href="./rfc5755" title=""An Internet Attribute Certificate Profile for Authorization"">RFC5755</a>]. Definition of an equivalent
LDAP schema is left to a future specification.
<span class="h3"><a class="selflink" id="section-1.1" href="#section-1.1">1.1</a>. Terminology</span>
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 [<a href="./rfc2119" title=""Key words for use in RFCs to Indicate Requirement Levels"">RFC2119</a>].
<span class="h3"><a class="selflink" id="section-1.2" href="#section-1.2">1.2</a>. ASN.1 Syntax Notation</span>
The attribute is defined using ASN.1 [<a href="#ref-X.680">X.680</a>], [<a href="#ref-X.681">X.681</a>], [<a href="#ref-X.682">X.682</a>], and
[<a href="#ref-X.683">X.683</a>].
<span class="h2"><a class="selflink" id="section-2" href="#section-2">2</a>. Clearance Sponsor</span>
The clearance sponsor attribute, which is only meaningful if the
clearance attribute [<a href="./rfc5755" title=""An Internet Attribute Certificate Profile for Authorization"">RFC5755</a>] [<a href="./rfc5912" title=""New ASN.1 Modules for the Public Key Infrastructure Using X.509 (PKIX)"">RFC5912</a>] 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
[<a href="./rfc5280" title=""Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile"">RFC5280</a>], 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.
<span class="h2"><a class="selflink" id="section-3" href="#section-3">3</a>. Security Considerations</span>
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.
<span class="h2"><a class="selflink" id="section-4" href="#section-4">4</a>. References</span>
<span class="h3"><a class="selflink" id="section-4.1" href="#section-4.1">4.1</a>. Normative References</span>
[<a id="ref-RFC2119">RFC2119</a>] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", <a href="https://www.rfc-editor.org/bcp/bcp14">BCP 14</a>, <a href="./rfc2119">RFC 2119</a>, March 1997.
[<a id="ref-RFC5280">RFC5280</a>] 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", <a href="./rfc5280">RFC 5280</a>, May 2008.
[<a id="ref-RFC5755">RFC5755</a>] Farrell, S., Housley, R., and S. Turner, "An Internet
Attribute Certificate Profile for Authorization", <a href="./rfc5755">RFC</a>
<a href="./rfc5755">5755</a>, January 2010.
[<a id="ref-RFC5912">RFC5912</a>] Schaad, J. and P. Hoffman, "New ASN.1 Modules for the
Public Key Infrastructure Using X.509 (PKIX)", <a href="./rfc5912">RFC 5912</a>,
June 2010.
[<a id="ref-X.520">X.520</a>] ITU-T Recommendation X.520 (2002) | ISO/IEC 9594-6:2002,
Information technology - The Directory:Selected Attribute
Types.
[<a id="ref-X.680">X.680</a>] ITU-T Recommendation X.680 (2002) | ISO/IEC 8824-1:2002,
Information technology - Abstract Syntax Notation One
(ASN.1): Specification of basic notation.
[<a id="ref-X.681">X.681</a>] ITU-T Recommendation X.681 (2002) | ISO/IEC 8824-2:2002,
Information Technology - Abstract Syntax Notation One:
Information Object Specification.
[<a id="ref-X.682">X.682</a>] ITU-T Recommendation X.682 (2002) | ISO/IEC 8824-3:2002,
Information Technology - Abstract Syntax Notation One:
Constraint Specification.
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[<a id="ref-X.683">X.683</a>] ITU-T Recommendation X.683 (2002) | ISO/IEC 8824-4:2002,
Information Technology - Abstract Syntax Notation One:
Parameterization of ASN.1 Specifications.
<span class="h3"><a class="selflink" id="section-4.2" href="#section-4.2">4.2</a>. Informative References</span>
[<a id="ref-RFC3114">RFC3114</a>] Nicolls, W., "Implementing Company Classification Policy
with the S/MIME Security Label", <a href="./rfc3114">RFC 3114</a>, May 2002.
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<span class="h2"><a class="selflink" id="appendix-A" href="#appendix-A">Appendix A</a>. ASN.1 Module</span>
This appendix provides the normative ASN.1 [<a href="#ref-X.680">X.680</a>] definitions for
the structures described in this specification using ASN.1 as defined
in [<a href="#ref-X.680">X.680</a>], [<a href="#ref-X.681">X.681</a>], [<a href="#ref-X.682">X.682</a>], and [<a href="#ref-X.683">X.683</a>].
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 [<a href="./rfc5912" title=""New ASN.1 Modules for the Public Key Infrastructure Using X.509 (PKIX)"">RFC5912</a>]
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 [<a href="./rfc5912" title=""New ASN.1 Modules for the Public Key Infrastructure Using X.509 (PKIX)"">RFC5912</a>]
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 [<a href="#ref-X.520">X.520</a>]
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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