Network Working Group Sean Turner, IECA
Internet Draft February 1, 2010
Intended Status: Informational Track
Expires: August 1, 2010
Clearance Sponsor Attribute
draft-turner-clearancesponsor-attribute-03.txt
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
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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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]. 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 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] through [X.683].
2. Clearance Sponsor
The clearance sponsor attribute, which is only meaningful if the
clearance attribute [RFC5755] is also present, indicates the sponsor
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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, string with a
minimum size of 1 characters and a maximum of 64 characters.
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 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
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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 the
two as strings as equivalent 2) indicate the sponsor as well as the
trust anchor. To solve this problem, a mechanism, which is out side
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. IANA Considerations
None: All identifiers are already registered. Please remove this
section prior to publication as an RFC.
5. References
5.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5280] Cooper, D., et.al., "Internet X.509 Public Key
Infrastructure Certificate and Certification
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.
[RFCTBD] Schaad, J., and P. Hoffman, "New ASN.1 Modules for
PKIX", draft-ietf-pkix-new-asn1-07.txt, work-in-
progress.
/**
RFC Editor: Please replace "RFCTBD" with "RFC####" where #### is the
number of the published RFC. Please do this in both the references
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and the text.
**/
[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.
[X.683] ITU-T Recommendation X.683 (2002) | ISO/IEC 8824-
4:2002. Information Technology - Abstract Syntax
Notation One: Parameterization of ASN.1
Specifications.
5.2. 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] through [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 [RFCTBD]
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 [RFCTBD]
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 }
;
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-- 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
}
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: turners@ieca.com
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