< draft-ietf-stir-certificates-02.txt		draft-ietf-stir-certificates-03.txt >
	Network Working Group J. Peterson		Network Working Group J. Peterson
	Internet-Draft Neustar		Internet-Draft Neustar
	Intended status: Standards Track S. Turner		Intended status: Standards Track S. Turner
	Expires: January 6, 2016 IECA		Expires: September 22, 2016 Sn3rd
	July 5, 2015		March 21, 2016
	Secure Telephone Identity Credentials: Certificates		Secure Telephone Identity Credentials: Certificates
	draft-ietf-stir-certificates-02.txt		draft-ietf-stir-certificates-03.txt
	Abstract		Abstract
	In order to prove ownership of telephone numbers on the Internet,		In order to prevent the impersonation of telephone numbers on the
	some kind of public infrastructure needs to exist that binds		Internet, some kind of credential system needs to exist that
	cryptographic keys to authority over telephone numbers. This		cryptographically proves authority over telephone numbers. This
	document describes a certificate-based credential system for		document describes the use of certificates in establishing authority
	telephone numbers, which could be used as a part of a broader		over telephone numbers, as a component of a broader architecture for
	architecture for managing telephone numbers as identities in		managing telephone numbers as identities in protocols like SIP.
	protocols like SIP.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.		Drafts is at http://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on January 6, 2016.		This Internet-Draft will expire on September 22, 2016.
	Copyright Notice		Copyright Notice
	Copyright (c) 2015 IETF Trust and the persons identified as the		Copyright (c) 2016 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3		2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
	3. Enrollment and Authorization . . . . . . . . . . . . . . . . 3		3. Authority for Telephone Numbers in Certificates . . . . . . . 3
	3.1. Certificate Scope and Structure . . . . . . . . . . . . . 4		4. Enrollment and Authorization using the TN Authorization List 5
	3.2. Provisioning Private Keying Material . . . . . . . . . . 5		4.1. Certificate Extension Scope and Structure . . . . . . . . 6
	4. Acquiring Credentials to Verify Signatures . . . . . . . . . 5		5. Provisioning Private Keying Material . . . . . . . . . . . . 7
	4.1. Verifying Certificate Scope . . . . . . . . . . . . . . . 6		6. Acquiring Credentials to Verify Signatures . . . . . . . . . 7
	4.2. Certificate Freshness and Revocation . . . . . . . . . . 8		7. Verifying Certificate Scope with TN Authorization List . . . 8
	4.2.1. Choosing a Verification Method . . . . . . . . . . . 8		8. Certificate Freshness and Revocation . . . . . . . . . . . . 10
	4.2.2. Using OCSP with STIR Certificates . . . . . . . . . . 9		8.1. Choosing a Verification Method . . . . . . . . . . . . . 10
	4.2.2.1. OCSP Extension Specification . . . . . . . . . . 10		8.2. Using OCSP with TN Auth List . . . . . . . . . . . . . . 11
	4.2.3. Acquiring TN Lists By Reference . . . . . . . . . . . 11		8.2.1. OCSP Extension Specification . . . . . . . . . . . . 12
	5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12		8.3. Acquiring TN Lists By Reference . . . . . . . . . . . . . 13
	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12		9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14
	7. Security Considerations . . . . . . . . . . . . . . . . . . . 12		10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
	8. Informative References . . . . . . . . . . . . . . . . . . . 12		11. Security Considerations . . . . . . . . . . . . . . . . . . . 15
	Appendix A. ASN.1 Module . . . . . . . . . . . . . . . . . . . . 14		12. Informative References . . . . . . . . . . . . . . . . . . . 15
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15		Appendix A. ASN.1 Module . . . . . . . . . . . . . . . . . . . . 17
			Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
	1. Introduction		1. Introduction
	As is discussed in the STIR problem statement		The STIR problem statement [I-D.ietf-stir-problem-statement]
	[I-D.ietf-stir-problem-statement], the primary enabler of		identifies the primary enabler of robocalling, vishing, swatting and
	robocalling, vishing, swatting and related attacks is the capability		related attacks as the capability to impersonate a calling party
	to impersonate a calling party number. The starkest examples of		number. The starkest examples of these attacks are cases where
	these attacks are cases where automated callees on the PSTN rely on		automated callees on the PSTN rely on the calling number as a
	the calling number as a security measure, for example to access a		security measure, for example to access a voicemail system.
	voicemail system. Robocallers use impersonation as a means of		Robocallers use impersonation as a means of obscuring identity; while
	obscuring identity; while robocallers can, in the ordinary PSTN,		robocallers can, in the ordinary PSTN, block (that is, withhold)
	block (that is, withhold) their caller identity, callees are less		their caller identity, callees are less likely to pick up calls from
	likely to pick up calls from blocked identities, and therefore		blocked identities, and therefore appearing to calling from some
	appearing to calling from some number, any number, is preferable.		number, any number, is preferable. Robocallers however prefer not to
	Robocallers however prefer not to call from a number that can trace		call from a number that can trace back to the robocaller, and
	back to the robocaller, and therefore they impersonate numbers that		therefore they impersonate numbers that are not assigned to them.
	are not assigned to them.
	One of the most important components of a system to prevent		One of the most important components of a system to prevent
	impersonation is an authority responsible for issuing credentials to		impersonation is the implementation of credentials which identify the
	parties who control telephone numbers. With these credentials,		parties who control telephone numbers. With these credentials,
	parties can prove that they are in fact authorized to use telephony		parties can prove that they are in fact authorized to use telephony
	numbers, and thus distinguish themselves from impersonators unable to		numbers, and thus distinguish themselves from impersonators unable to
	present credentials. This document describes a credential system for		present such credentials. This document describes credential systems
	telephone numbers based on X.509 version 3 certificates in accordance		for telephone numbers based on X.509 version 3 certificates in
	with [RFC5280]. While telephone numbers have long been a part of the		accordance with [RFC5280]. While telephone numbers have long been a
	X.509 standard, the certificates described in this document may		part of the X.509 standard, this document extends X.509 with a
	contain telephone number blocks or ranges, and accordingly it uses an		Telephone Number Authorization List which binds certificates to
	alternate syntax.		authority for particular telephone numbers, or potentially telephone
			number blocks or ranges.
	In the STIR in-band architecture, two basic types of entities need		In the STIR in-band architecture specified in
	access to these credentials: authentication services, and		[I-D.ietf-stir-rfc4474bis], two basic types of entities need access
	verification services (or verifiers); see [I-D.ietf-stir-rfc4474bis].		to these credentials: authentication services, and verification
	An authentication service must be operated by an entity enrolled with		services (or verifiers). An authentication service must be operated
	the certification authority (see Section 3), whereas a verifier need		by an entity enrolled with the certification authority (see
	only trust the root certificate of the authority, and have a means to		Section 4), whereas a verifier need only trust the root certificate
	acquire and validate certificates.		of the authority, and have a means to access and validate the public
			keys associated with these certificates. Although the guidance in
			this document is written with the STIR in-band architecture in mind,
			the credential system described in this document could be useful for
			other protocols that want to make use of certificates to prove
			authority over telephone numbers on the Internet.
	This document attempts to specify only the basic elements necessary		This document specifies only the credential syntax and semantics
	for this architecture. Only through deployment experience will it be		necessary to support this architecture. It does not assume any
	possible to decide directions for future work.		particular certification authority or deployment environment. We
			anticipate that some deployment experience will be necessary to
			determine optimal operational models.
	2. Terminology		2. Terminology
	In this document, the key words "MUST", "MUST NOT", "REQUIRED",		In this document, the key words "MUST", "MUST NOT", "REQUIRED",
	"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT		"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT
	RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as		RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as
	described in RFC 2119 [RFC2119] and RFC 6919 [RFC6919].		described in RFC 2119 [RFC2119] and RFC 6919 [RFC6919].
	3. Enrollment and Authorization		3. Authority for Telephone Numbers in Certificates
	This document assumes a threefold model for certificate enrollment.		At a high level, this specification details two non-exclusive
			approaches that can be employed to determine authority over telephone
			numbers with certificates.
			The first approach is to leverage the subject of the certificate to
			ascertain that the holder of the certificate is authorized to claim
			authority over a telephone number. The subject might be represented
			as a domain name in the SubjectAltName, such as an "example.net"
			where that domain is known to relying parties as a carrier, or
			represented with other identifiers related to the operation of the
			telephone network including Service Provider Identifiers (SPIDs)
			could serve as a subject as well. A relying party could then employ
			an external data set or service that determines whether or not a
			specific telephone number is under the authority of the carrier
			identified as the subject of the certificate, and use that to
			ascertain whether or not the carrier should have authority over a
			telephone number. Potentially, a certificate extension to convey the
			URI of such an information service trusted by the issuer of the
			certificate could be developed (though this specification does not
			propose one). Alternatively, some relying parties could form
			bilateral or multilateral trust relationships with peer carriers,
			trusting one another's assertions just as telephone carriers in the
			SS7 network today rely on transitive trust when displaying the
			calling party telephone number received through SS7 signaling.
			The second approach is to extend the syntax of certificates to
			include a new attribute, defined here as TN Authorization List, which
			contains a list of telephone numbers defining the scope of authority
			of the certificate. Relying parties, if they trust the issuer of the
			certificate as a source of authoritative information on telephone
			numbers, could therefore use the TN Authorization List instead of the
			subject of the certificate to make a decision about whether or not
			the signer has authority over a particular telephone number. The TN
			Authorization List could be provided in one of two ways: as a literal
			value in the certificate, or as a network service that allows relying
			parties to query in real time to determine that a telephone number is
			in the scope of a certificate. Using the TN Authorization list
			rather than the certificate subject makes sense when, for example,
			for privacy reasons, the certificate owner would prefer not to be
			identified, or in cases where the holder of the certificate does not
			participate in the sort of traditional carrier infrastructure taht
			the first approach assumes.
			The first approach requires little change to existing PKI
			certificates; for the second approach, we must define an appropriate
			enrollment and authorization process. For the purposes of STIR, the
			over-the-wire format specified in [I-D.ietf-stir-rfc4474bis]
			accommodates either of these approaches: the methods for
			canonicalizing, signing, for identifying and accessing the
			certificate and so on remain the same; it is only the verifier
			behavior and authorization decision that will change depending on the
			approach to telephone number authority taken by the certificate. For
			that reason, the two approaches are not mutually exclusive, and in
			fact a certificate issued to a traditional telephone network service
			provider could contain a TN Authorization List or not, depending on
			the certification authority issuing the credential. Regardless of
			which approaches is used, certificates that assert authority over
			telephone numbers are subject to the ordinary operational procedures
			that govern certificate use per [RFC5280]. This means that
			verification services must be mindful of the need to ensure that they
			trust the root certificate authority that issued the certificate, and
			that they have some means to determine the freshness of the
			certificate (see Section 8).
			4. Enrollment and Authorization using the TN Authorization List
			This document assumes a threefold model for certificate enrollment
			when using the TN Authorization List extension.
	The first enrollment model is one where the certification authority		The first enrollment model is one where the certification authority
	acts in concert with national numbering authorities to issue		acts in concert with national numbering authorities to issue
	credentials to those parties to whom numbers are assigned. In the		credentials to those parties to whom numbers are assigned. In the
	United States, for example, telephone number blocks are assigned to		United States, for example, telephone number blocks are assigned to
	Local Exchange Carriers (LECs) by the North American Numbering Plan		Local Exchange Carriers (LECs) by the North American Numbering Plan
	Administrator (NANPA), who is in turn directed by the national		Administrator (NANPA), who is in turn directed by the national
	regulator. LECs may also receive numbers in smaller allocations,		regulator. LECs may also receive numbers in smaller allocations,
	through number pooling, or via an individual assignment through		through number pooling, or via an individual assignment through
	number portability. LECs assign numbers to customers, who may be		number portability. LECs assign numbers to customers, who may be
	private individuals or organizations - and organizations take		private individuals or organizations - and organizations take
	responsibility for assigning numbers within their own enterprise.		responsibility for assigning numbers within their own enterprise.
			This model requires top-down adoption of the model from regulators
			through to carriers.
	The second enrollment model is one where a certification authority		The second enrollment model is a bottom-up approach where a
	requires that an entity prove control by means of some sort of test.		certification authority requires that an entity prove control by
	For example, an authority might send a text message to a telephone		means of some sort of test, which, as with certification authorities
	number containing a URL (which might be dereferenced by the		for web PKI, might either be automated or a manual administrative
	recipient) as a means of verifying that a user has control of		process. As an example of an automated process, an authority might
	terminal corresponding to that number. Checks of this form are		send a text message to a telephone number containing a URL (which
	frequently used in commercial systems today to validate telephone		might be dereferenced by the recipient) as a means of verifying that
	numbers provided by users. This is comparable to existing enrollment		a user has control of terminal corresponding to that number. Checks
	systems used by some certificate authorities for issuing S/MIME		of this form are frequently used in commercial systems today to
	credentials for email by verifying that the party applying for a		validate telephone numbers provided by users. This is comparable to
	credential receives mail at the email address in question.		existing enrollment systems used by some certificate authorities for
			issuing S/MIME credentials for email by verifying that the party
			applying for a credential receives mail at the email address in
			question.
	The third enrollment model is delegation: that is, the holder of a		The third enrollment model is delegation: that is, the holder of a
	certificate (assigned by either of the two methods above) may		certificate (assigned by either of the two methods above) might
	delegate some or all of their authority to another party. In some		delegate some or all of their authority to another party. In some
	cases, multiple levels of delegation could occur: a LEC, for example,		cases, multiple levels of delegation could occur: a LEC, for example,
	might delegate authority to customer organization for a block of 100		might delegate authority to a customer organization for a block of
	numbers, and the organization might in turn delegate authority for a		100 numbers used by an IP PBX, and the organization might in turn
	particular number to an individual employee. This is analogous to		delegate authority for a particular number to an individual employee.
	delegation of organizational identities in traditional hierarchical		This is analogous to delegation of organizational identities in
	Public Key Infrastructures (PKIs) who use the name constraints		traditional hierarchical Public Key Infrastructures (PKIs) who use
	extension [RFC5280]; the root CA delegates names in sales to the		the name constraints extension [RFC5280]; the root CA delegates names
	sales department CA, names in development to the development CA, etc.		in sales to the sales department CA, names in development to the
	As lengthy certificate delegation chains are brittle, however, and		development CA, etc. As lengthy certificate delegation chains are
	can cause delays in the verification process, this document considers		brittle, however, and can cause delays in the verification process,
	optimizations to reduce the complexity of verification.		this document considers optimizations to reduce the complexity of
			verification.
	[TBD] Future versions of this specification may address adding a		[TBD] Future versions of this specification may address adding a
	level of assurance indication to certificates to differentiate those		level of assurance indication to certificates to differentiate those
	enrolled from proof-of-possession versus delegation.		enrolled from proof-of-possession versus delegation.
	[TBD] Future versions of this specification may also discuss methods		[TBD] Future versions of this specification may also discuss methods
	of partial delegation, where certificate holders delegate only part		of partial delegation, where certificate holders delegate only part
	of their authority. For example, individual assignees may want to		of their authority. For example, individual assignees may want to
	delegate to a service authority for text messages associated with		delegate to a service authority for text messages associated with
	their telephone number, but not for other functions.		their telephone number, but not for other functions.
	3.1. Certificate Scope and Structure		4.1. Certificate Extension Scope and Structure
	The subjects of telephone number certificates are the administrative
	entities to whom numbers are assigned or delegated. For example, a
	LEC might hold a certificate for a range of telephone numbers.
	[TBD - what if the subject is considered a privacy leak?]
	This specification places no limits on the number of telephone		This specification places no limits on the number of telephone
	numbers that can be associated with any given certificate. Some		numbers that can be associated with any given certificate. Some
	service providers may be assigned millions of numbers, and may wish		service providers may be assigned millions of numbers, and may wish
	to have a single certificate that is capable of signing for any one		to have a single certificate that is capable of signing for any one
	of those numbers. Others may wish to compartmentalize authority over		of those numbers. Others may wish to compartmentalize authority over
	subsets of the numbers they control.		subsets of the numbers they control.
	Moreover, service providers may wish to have multiple certificates		Moreover, service providers may wish to have multiple certificates
	with the same scope of authority. For example, a service provider		with the same scope of authority. For example, a service provider
	with several regional gateway systems may want each system to be		with several regional gateway systems may want each system to be
	capable of signing for each of their numbers, but not want to have		capable of signing for each of their numbers, but not want to have
	each system share the same private key.		each system share the same private key.
	The set of telephone numbers for which a particular certificate is		The set of telephone numbers for which a particular certificate is
	valid is expressed in the certificate through a certificate		valid is expressed in the certificate through a certificate
	extension; the certificate's extensibility mechanism is defined in		extension; the certificate's extensibility mechanism is defined in
	[RFC5280] but the telephone number authorization extension is defined		[RFC5280] but the TN Authorization List extension is specified in
	in this document.		this document.
	3.2. Provisioning Private Keying Material		The subjects of certificates containing the TN Authorization List
			extension are typically the administrative entities to whom numbers
			are assigned or delegated. For example, a LEC might hold a
			certificate for a range of telephone numbers. In some cases, the
			organization or individual issued such a certificate may not want to
			associate themselves with a certificate; for example, a private
			individual with a certificate for a single telephone number might not
			want to distribute that certificate publicly if every verifier
			immediately knew their name. The certification authorities issuing
			certificates with the TN Authorization List extensions may, in
			accordance with their policies, obscure the identity of the subject,
			though mechanisms for doing so are outside the scope of this
			document.
			5. Provisioning Private Keying Material
	In order for authentication services to sign calls via the procedures		In order for authentication services to sign calls via the procedures
	described in [I-D.ietf-stir-rfc4474bis], they must possess a private		described in [I-D.ietf-stir-rfc4474bis], they must hold a private key
	key corresponding to a certificate with authority over the calling		corresponding to a certificate with authority over the calling
	number. This specification does not require that any particular		number. This specification does not require that any particular
	entity sign requests, only that it be an entity with an appropriate		entity in a SIP deployment architecture sign requests, only that it
	private key; the authentication service role may be instantiated by		be an entity with an appropriate private key; the authentication
	any entity in a SIP network. For a certificate granting authority		service role may be instantiated by any entity in a SIP network. For
	only over a particular number which has been issued to an end user,		a certificate granting authority only over a particular number which
	for example, an end user device might hold the private key and		has been issued to an end user, for example, an end user device might
	generate the signature. In the case of a service provider with		hold the private key and generate the signature. In the case of a
	authority over large blocks of numbers, an intermediary might hold		service provider with authority over large blocks of numbers, an
	the private key and sign calls.		intermediary might hold the private key and sign calls.
	The specification recommends distribution of private keys through		The specification recommends distribution of private keys through
	PKCS#8 objects signed by a trusted entity, for example through the		PKCS#8 objects signed by a trusted entity, for example through the
	CMS package specified in [RFC5958].		CMS package specified in [RFC5958].
	4. Acquiring Credentials to Verify Signatures		6. Acquiring Credentials to Verify Signatures
	This specification documents multiple ways that a verifier can gain		This specification documents multiple ways that a verifier can gain
	access to the credentials needed to verify a request. As the		access to the credentials needed to verify a request. As the
	validity of certificates does not depend on the circumstances of		validity of certificates does not depend on the method of their
	their acquisition, there is no need to standardize any single		acquisition, there is no need to standardize any single mechanism for
	mechanism for this purpose. All entities that comply with		this purpose. All entities that comply with
	[I-D.ietf-stir-rfc4474bis] necessarily support SIP, and consequently		[I-D.ietf-stir-rfc4474bis] necessarily support SIP, and consequently
	SIP itself can serve as a way to acquire certificates. This specific		SIP itself can serve as a way to acquire certificates.
	does allow delivery through alternate means as well.		[I-D.ietf-stir-rfc4474bis] provides an "info" parameter of the
			Identity header which contains a URI where the credential used to
			generate the Identity header, and requires documents which define
			credential systems to list the URI schemes that may be present in the
			"info" parameter. For implementations compliant with this
			specification, three URI schemes are REQUIRED: the CID URI, the SIP
			URI, and the HTTP URI.
	The simplest way for a verifier to acquire the certificate needed to		The simplest way for a verifier to acquire the certificate needed to
	verify a signature is for the certificate be conveyed along with the		verify a signature is for the certificate be conveyed in a SIP
	signature itself. In SIP, for example, a certificate could be		request along with the signature itself. In SIP, for example, a
	carried in a multipart MIME body [RFC2046], and the URI in the		certificate could be carried in a multipart MIME body [RFC2046], and
	Identity-Info header could specify that body with a CID URI		the URI in the Identity header "info" parameter could specify that
	[RFC2392]. However, in many environments this is not feasible due to		body with a CID URI [RFC2392]. However, in many environments this is
	message size restrictions or lack of necessary support for multipart		not feasible due to message size restrictions or lack of necessary
	MIME.		support for multipart MIME.
	Alternatively, the Identity-Info header of a SIP request may contain		More commonly, the Identity header "info" parameter in a SIP request
	a URI that the verifier dereferences with a network call.		may contain a URI that the verifier dereferences with a network call.
	Implementations of this specification are required to support the use		Implementations of this specification are required to support the use
	of SIP for this function (via the SUBSCRIBE/NOTIFY mechanism), as		of SIP for this function (via the SUBSCRIBE/NOTIFY mechanism), as
	well as HTTP, via the Enrollment over Secure Transport mechanisms		well as HTTP, via the Enrollment over Secure Transport mechanisms
	described in RFC 7030 [RFC7030].		described in RFC 7030 [RFC7030].
	A verifier can however have access to a service that grants access to		Note well that as an optimization, a verifier may have access to a
	certificates for a particular telephone number. Note however that		service, a cache or other local store that grants access to
	there may be multiple valid certificates that can sign a call setup		certificates for a particular telephone number. However, there may
	request for a telephone number, and that as a consequence, there		be multiple valid certificates that can sign a call setup request for
	needs to be some discriminator that the signer uses to identify their		a telephone number, and as a consequence, there needs to be some
	credentials. The Identity-Info header itself can serve as such a		discriminator that the signer uses to identify their credentials.
	discriminator.		The Identity header "info" parameter itself can serve as such a
			discriminator, provided implementations use that parameter as a key
			when accessing certificates from caches or other sources. Verifiers
			still
	4.1. Verifying Certificate Scope		7. Verifying Certificate Scope with TN Authorization List
	The subjects of these certificates are the administrative entities to		The subjects of certificates containing the TN Authorization List
	whom numbers are assigned or delegated. When a verifier is		extension are the administrative entities to whom numbers are
	validating a caller's identity, local policy always determines the		assigned or delegated. When a verifier is validating a caller's
	circumstances under which any particular subject may be trusted, but		identity, local policy always determines the circumstances under
	for the purpose of validating a caller's identity, this certificate		which any particular subject may be trusted, but the purpose of the
	extension establishes whether or not a signer is authorized to sign		TN Authorization List extension particular is to allow a verifier to
	for a particular number.		ascertain when the certification authority has designed that the
			subject has authority over a particular telephone number or number
			range.
	The Telephony Number (TN) Authorization List certificate extension is		The Telephony Number (TN) Authorization List certificate extension is
	identified by the following object identifier:		identified by the following object identifier:
	id-ce-TNAuthList OBJECT IDENTIFIER ::= { TBD }		id-ce-TNAuthList OBJECT IDENTIFIER ::= { TBD }
	The TN Authorization List certificate extension has the following		The TN Authorization List certificate extension has the following
	syntax:		syntax:
	TNAuthorizationList ::= SEQUENCE SIZE (1..MAX) OF TNAuthorization		TNAuthorizationList ::= SEQUENCE SIZE (1..MAX) OF TNAuthorization
	skipping to change at page 8, line 11 ¶		skipping to change at page 10, line 11 ¶
	many numbers, possibly millions of numbers, with a particular		many numbers, possibly millions of numbers, with a particular
	certificate, optimizations are required for those cases to prevent		certificate, optimizations are required for those cases to prevent
	certificate size from becoming unmanageable. In these cases, the TN		certificate size from becoming unmanageable. In these cases, the TN
	Authorization List may be given by reference rather than by value,		Authorization List may be given by reference rather than by value,
	through the presence of a separate certificate extension that permits		through the presence of a separate certificate extension that permits
	verifiers to either securely download the list of numbers associated		verifiers to either securely download the list of numbers associated
	with a certificate, or to verify that a single number is under the		with a certificate, or to verify that a single number is under the
	authority of this certificate. This optimization will be detailed in		authority of this certificate. This optimization will be detailed in
	future version of this specification.		future version of this specification.
	4.2. Certificate Freshness and Revocation		8. Certificate Freshness and Revocation
	The problem of certificate freshness gains a new wrinkle in the		Regardless of which of the approaches in Section 3 is followed for
	telephone number context, because verifiers must establish not only		using certificates, some sort of certificate verification mechanism
	that a certificate remains valid, but also that the certificate's		is required. However, the traditional problem of certificate
	scope contains the telephone number that the verifier is validating.		freshness gains a new wrinkle when using the TN Authorization List
			extension, because verifiers must establish not only that a
			certificate remains valid, but also that the certificate's scope
			contains the telephone number that the verifier is validating.
	Dynamic changes to number assignments can occur due to number		Dynamic changes to number assignments can occur due to number
	portability, for example. So even if a verifier has a valid cached		portability, for example. So even if a verifier has a valid cached
	certificate for a telephone number (or a range containing the		certificate for a telephone number (or a range containing the
	number), the verifier must determine that the entity that signed is		number), the verifier must determine that the entity that signed is
	still a proper authority for that number.		still a proper authority for that number.
	To verify the status of the certificate, the verifier needs the		To verify the status of the certificate, the verifier needs to
	certificate, which is included with the call, and then would need to		acquire the certificate if necessary (via the methods described in
	either:		Section 6), and then would need to either:
	Rely on short-lived certificates and not check the certificate's		Rely on short-lived certificates and not check the certificate's
	status, or		status, or
	Rely on status information from the authority		Rely on status information from the authority
	The tradeoff between short lived certificates and using status		The tradeoff between short lived certificates and using status
	information is the former's burden is on the front end (i.e.,		information is the former's burden is on the front end (i.e.,
	enrollment) and the latter's burden is on the back end (i.e.,		enrollment) and the latter's burden is on the back end (i.e.,
	verification). Both impact call setup time, but it is assumed that		verification). Both impact call setup time, but it is assumed that
	performing enrollment for each call is more of an impact that using		performing enrollment for each call is more of an impact that using
	status information. This document therefore recommends relying on		status information. This document therefore recommends relying on
	status information.		status information.
	4.2.1. Choosing a Verification Method		8.1. Choosing a Verification Method
	There are three common certificate verification mechanisms employed		There are three common certificate verification mechanisms employed
	by CAs:		by CAs:
	Certificate Revocation Lists (CRLs) [RFC5280]		Certificate Revocation Lists (CRLs) [RFC5280]
	Online Certificate Status Protocol (OCSP) [RFC6960], and		Online Certificate Status Protocol (OCSP) [RFC6960], and
	Server-based Certificate Validation Protocol (SCVP) [RFC5055].		Server-based Certificate Validation Protocol (SCVP) [RFC5055].
	When relying on status information, the verifier needs to obtain the		When relying on status information, the verifier needs to obtain the
	status information - but before that can happen, the verifier needs		status information - but before that can happen, the verifier needs
	to know where to locate it. Placing the location of the status		to know where to locate it. Placing the location of the status
	information in the certificate makes the certificate larger, but it		information in the certificate makes the certificate larger, but it
	eases the client workload. The CRL Distribution Point certificate		eases the client workload. The CRL Distribution Point certificate
	extension includes the location of the CRL and the Authority		extension includes the location of the CRL and the Authority
	Information Access certificate extension includes the location of		Information Access certificate extension includes the location of
	OCSP and/or SCVP servers; both of these extensions are defined in		OCSP and/or SCVP servers; both of these extensions are defined in
	skipping to change at page 9, line 34 ¶		skipping to change at page 11, line 35 ¶
	(i.e., does the RP have all of the CRL partitions).		(i.e., does the RP have all of the CRL partitions).
	CAs in the STIR architecture will likely all create CRLs for audit		CAs in the STIR architecture will likely all create CRLs for audit
	purposes, but it NOT RECOMMENDED that they be relying upon for status		purposes, but it NOT RECOMMENDED that they be relying upon for status
	information. Instead, one of the two "online" options is preferred.		information. Instead, one of the two "online" options is preferred.
	Between the two, OCSP is much more widely deployed and this document		Between the two, OCSP is much more widely deployed and this document
	therefore recommends the use of OCSP in high-volume environments for		therefore recommends the use of OCSP in high-volume environments for
	validating the freshness of certificates, based on [RFC6960],		validating the freshness of certificates, based on [RFC6960],
	incorporating some (but not all) of the optimizations of [RFC5019].		incorporating some (but not all) of the optimizations of [RFC5019].
	4.2.2. Using OCSP with STIR Certificates		8.2. Using OCSP with TN Auth List
	Certificates compliant with this specification therefore SHOULD		Certificates compliant with this specification therefore SHOULD
	include a URL pointing to an OCSP service in the Authority		include a URL pointing to an OCSP service in the Authority
	Information Access (AIA) certificate extension, via the "id-ad-ocsp"		Information Access (AIA) certificate extension, via the "id-ad-ocsp"
	accessMethod specified in [RFC5280]. Baseline OCSP however supports		accessMethod specified in [RFC5280]. Baseline OCSP however supports
	only three possible response values: good, revoked, or unknown. With		only three possible response values: good, revoked, or unknown. With
	some extension, OCSP would not indicate whether the certificate is		some extension, OCSP would not indicate whether the certificate is
	authorized for a particular telephone number that the verifier is		authorized for a particular telephone number that the verifier is
	validating.		validating.
	skipping to change at page 10, line 28 ¶		skipping to change at page 12, line 32 ¶
	we're6960 obviously going to change this to be SHA-256.		we're6960 obviously going to change this to be SHA-256.
	The requirement to consult OCSP in real time results in a network		The requirement to consult OCSP in real time results in a network
	round-trip time of day, which is something to consider because it		round-trip time of day, which is something to consider because it
	will add to the call setup time. OCSP server implementations		will add to the call setup time. OCSP server implementations
	commonly pre-generate responses, and to speed up HTTPS connections,		commonly pre-generate responses, and to speed up HTTPS connections,
	servers often provide OCSP responses for each certificate in their		servers often provide OCSP responses for each certificate in their
	hierarchy. If possible, both of these OCSP concepts should be		hierarchy. If possible, both of these OCSP concepts should be
	adopted for use with STIR.		adopted for use with STIR.
	4.2.2.1. OCSP Extension Specification		8.2.1. OCSP Extension Specification
	The extension mechanism for OCSP follows X.509 v3 certificate		The extension mechanism for OCSP follows X.509 v3 certificate
	extensions, and thus requires an OID, a criticality flag, and ASN.1		extensions, and thus requires an OID, a criticality flag, and ASN.1
	syntax as defined by the OID. The criticality specified here is		syntax as defined by the OID. The criticality specified here is
	optional: per [RFC6960] Section 4.4, support for all OCSP extensions		optional: per [RFC6960] Section 4.4, support for all OCSP extensions
	is optional. If the OCSP server does not understand the requested		is optional. If the OCSP server does not understand the requested
	extension, it will still provide the baseline validation of the		extension, it will still provide the baseline validation of the
	certificate itself. Moreover, in practical STIR deployments, the		certificate itself. Moreover, in practical STIR deployments, the
	issuer of the certificate will set the accessLocation for the OCSP		issuer of the certificate will set the accessLocation for the OCSP
	AIA extension to point to an OCSP service that supports this		AIA extension to point to an OCSP service that supports this
	skipping to change at page 11, line 27 ¶		skipping to change at page 13, line 29 ¶
	sort of asynchronous mechanism could notify and update the verifier		sort of asynchronous mechanism could notify and update the verifier
	if the scope of the certificate changes so that verifiers could		if the scope of the certificate changes so that verifiers could
	implement a cache. While not all possible categories of verifiers		implement a cache. While not all possible categories of verifiers
	could implement such behavior, some sort of event-driven notification		could implement such behavior, some sort of event-driven notification
	of certificate status is another potential subject of future work.		of certificate status is another potential subject of future work.
	One potential direction is that a future SIP SUBSCRIBE/NOTIFY-based		One potential direction is that a future SIP SUBSCRIBE/NOTIFY-based
	accessMethod for AIA might be defined (which would also be applicable		accessMethod for AIA might be defined (which would also be applicable
	to the method described in the following section) by some future		to the method described in the following section) by some future
	specification.		specification.
	4.2.3. Acquiring TN Lists By Reference		Strategies for stapling OCSP [RFC6961] have become common in some web
			PKI environments as an optimization which allows web servers to send
			up-to-date certificate status information acquired from OCSP to
			clients as TLS is negotiated. A similar mechanism could be
			implemented for SIP requests, in which the authentication service
			adds status information for its certificate to the SIP request, which
			would save the verifier the trouble of performing the OCSP dip
			itself. Especially for high-volume authentication and verification
			services, this could result in significant performance improvements.
			This is left as an optimization for future work.
			8.3. Acquiring TN Lists By Reference
	Acquiring a list of the telephone numbers associated with a		Acquiring a list of the telephone numbers associated with a
	certificate or its subject lends itself to an application-layer		certificate or its subject lends itself to an application-layer
	query/response interaction outside of OCSP, one which could be		query/response interaction outside of OCSP, one which could be
	initiated through a separate URI included in the certificate. The		initiated through a separate URI included in the certificate. The
	AIA extension (see [RFC5280]) supports such a mechanism: it		AIA extension (see [RFC5280]) supports such a mechanism: it
	designates an OID to identify the accessMethod and an accessLocation,		designates an OID to identify the accessMethod and an accessLocation,
	which would most likely be a URI. A verifier would then follow the		which would most likely be a URI. A verifier would then follow the
	URI to ascertain whether the list of TNs authorized for use by the		URI to ascertain whether the list of TNs authorized for use by the
	caller.		caller.
	HTTPS is the most obvious candidate for a protocol to be used for		HTTPS is the most obvious candidate for a protocol to be used for
	fetching the list of telephone number associated with a particular		fetching the list of telephone number associated with a particular
	certificate. This document defines a new AIA accessMethod, called		certificate. This document defines a new AIA accessMethod, called
	"id-ad-stir-tn", which uses the following AIA OID:		"id-ad-stir-tn", which uses the following AIA OID:
	id-ad-stir-tn OBJECT IDENTIFIER ::= { id-ad TBD }		id-ad-stir-tn OBJECT IDENTIFIER ::= { id-ad TBD }
	When the "id-ad-stir-tn" accessMethod is used, the accessLocation		When the "id-ad-stir-tn" accessMethod is used, the accessLocation
	MUST be an HTTPS URI. The document returned by dereferencing that		MUST be an HTTPS URI. The document returned by dereferencing that
	URI will contain the complete TN Authorization List (see Section 4.1)		URI will contain the complete TN Authorization List (see Section 7)
	for the certificate.		for the certificate.
	Delivering the entire list of telephone numbers associated with a		Delivering the entire list of telephone numbers associated with a
	particular certificate will divulge to STIR verifiers information		particular certificate will divulge to STIR verifiers information
	about telephone numbers other than the one associated with the		about telephone numbers other than the one associated with the
	particular call that the verifier is checking. In some environments,		particular call that the verifier is checking. In some environments,
	where STIR verifiers handle a high volume of calls, maintaining an		where STIR verifiers handle a high volume of calls, maintaining an
	up-to-date and complete cache for the numbers associated with crucial		up-to-date and complete cache for the numbers associated with crucial
	certificate holders could give an important boost to performance.		certificate holders could give an important boost to performance.
	5. Acknowledgments		9. Acknowledgments
	Russ Housley, Brian Rosen, Cullen Jennings and Eric Rescorla provided		Russ Housley, Brian Rosen, Cullen Jennings and Eric Rescorla provided
	key input to the discussions leading to this document.		key input to the discussions leading to this document.
	6. IANA Considerations		10. IANA Considerations
	This document makes use of object identifiers for the TN Certificate		This document makes use of object identifiers for the TN Certificate
	Extension defined in Section 4.1, TN-HVE OCSP extension in		Extension defined in Section 7, TN-HVE OCSP extension in
	Section 4.2.2.1, and the TN by reference AIA access descriptor		Section 8.2.1, and the TN by reference AIA access descriptor defined
	defined in Section 4.2.3. It therefore requests that the IANA make		in Section 8.3. It therefore requests that the IANA make the
	the following assignments:		following assignments:
	- TN Certificate Extension in the SMI Security for PKIX		- TN Certificate Extension in the SMI Security for PKIX
	Certificate Extension registry: http://www.iana.org/assignments/		Certificate Extension registry: http://www.iana.org/assignments/
	smi-numbers/smi-numbers.xhtml#smi-numbers-1.3.6.1.5.5.7.1		smi-numbers/smi-numbers.xhtml#smi-numbers-1.3.6.1.5.5.7.1
	- TN-HVE OCSP extension in the SMI Security for PKIX Online		- TN-HVE OCSP extension in the SMI Security for PKIX Online
	Certificate Status Protocol (OCSP) registry:		Certificate Status Protocol (OCSP) registry:
	http://www.iana.org/assignments/smi-numbers/smi-numbers.xhtml#smi-		http://www.iana.org/assignments/smi-numbers/smi-numbers.xhtml#smi-
	numbers-1.3.6.1.5.5.7.48.1		numbers-1.3.6.1.5.5.7.48.1
	- TNS by reference access descriptor in the SMI Security for PKIX		- TNS by reference access descriptor in the SMI Security for PKIX
	Access Descriptor registry: http://www.iana.org/assignments/smi-		Access Descriptor registry: http://www.iana.org/assignments/smi-
	numbers/smi-numbers.xhtml#smi-numbers-1.3.6.1.5.5.7.48		numbers/smi-numbers.xhtml#smi-numbers-1.3.6.1.5.5.7.48
	7. Security Considerations		11. Security Considerations
	This document is entirely about security. For further information on		This document is entirely about security. For further information on
	certificate security and practices, see RFC 3280 [RFC3280], in		certificate security and practices, see RFC 3280 [RFC3280], in
	particular its Security Considerations.		particular its Security Considerations.
	8. Informative References		12. Informative References
	[I-D.ietf-stir-problem-statement]		[I-D.ietf-stir-problem-statement]
	Peterson, J., Schulzrinne, H., and H. Tschofenig, "Secure		Peterson, J., Schulzrinne, H., and H. Tschofenig, "Secure
	Telephone Identity Problem Statement and Requirements",		Telephone Identity Problem Statement and Requirements",
	draft-ietf-stir-problem-statement-05 (work in progress),		draft-ietf-stir-problem-statement-05 (work in progress),
	May 2014.		May 2014.
	[I-D.ietf-stir-rfc4474bis]		[I-D.ietf-stir-rfc4474bis]
	Peterson, J., Jennings, C., and E. Rescorla,		Peterson, J., Jennings, C., Rescorla, E., and C. Wendt,
	"Authenticated Identity Management in the Session		"Authenticated Identity Management in the Session
	Initiation Protocol (SIP)", draft-ietf-stir-rfc4474bis-03		Initiation Protocol (SIP)", draft-ietf-stir-rfc4474bis-07
	(work in progress), March 2015.		(work in progress), February 2016.
	[I-D.peterson-sipping-retarget]		[I-D.peterson-sipping-retarget]
	Peterson, J., "Retargeting and Security in SIP: A		Peterson, J., "Retargeting and Security in SIP: A
	Framework and Requirements", draft-peterson-sipping-		Framework and Requirements", draft-peterson-sipping-
	retarget-00 (work in progress), February 2005.		retarget-00 (work in progress), February 2005.
	[RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail		[RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
	Extensions (MIME) Part Two: Media Types", RFC 2046,		Extensions (MIME) Part Two: Media Types", RFC 2046,
	November 1996.		DOI 10.17487/RFC2046, November 1996,
			<http://www.rfc-editor.org/info/rfc2046>.
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119, March 1997.		Requirement Levels", BCP 14, RFC 2119,
			DOI 10.17487/RFC2119, March 1997,
			<http://www.rfc-editor.org/info/rfc2119>.
	[RFC2392] Levinson, E., "Content-ID and Message-ID Uniform Resource		[RFC2392] Levinson, E., "Content-ID and Message-ID Uniform Resource
	Locators", RFC 2392, August 1998.		Locators", RFC 2392, DOI 10.17487/RFC2392, August 1998,
			<http://www.rfc-editor.org/info/rfc2392>.
	[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.		[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818,
			DOI 10.17487/RFC2818, May 2000,
			<http://www.rfc-editor.org/info/rfc2818>.
	[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,		[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
	A., Peterson, J., Sparks, R., Handley, M., and E.		A., Peterson, J., Sparks, R., Handley, M., and E.
	Schooler, "SIP: Session Initiation Protocol", RFC 3261,		Schooler, "SIP: Session Initiation Protocol", RFC 3261,
	June 2002.		DOI 10.17487/RFC3261, June 2002,
			<http://www.rfc-editor.org/info/rfc3261>.
	[RFC3263] Rosenberg, J. and H. Schulzrinne, "Session Initiation		[RFC3263] Rosenberg, J. and H. Schulzrinne, "Session Initiation
	Protocol (SIP): Locating SIP Servers", RFC 3263, June		Protocol (SIP): Locating SIP Servers", RFC 3263,
	2002.		DOI 10.17487/RFC3263, June 2002,
			<http://www.rfc-editor.org/info/rfc3263>.
	[RFC3280] Housley, R., Polk, W., Ford, W., and D. Solo, "Internet		[RFC3280] Housley, R., Polk, W., Ford, W., and D. Solo, "Internet
	X.509 Public Key Infrastructure Certificate and		X.509 Public Key Infrastructure Certificate and
	Certificate Revocation List (CRL) Profile", RFC 3280,		Certificate Revocation List (CRL) Profile", RFC 3280,
	April 2002.		DOI 10.17487/RFC3280, April 2002,
			<http://www.rfc-editor.org/info/rfc3280>.
	[RFC5019] Deacon, A. and R. Hurst, "The Lightweight Online		[RFC5019] Deacon, A. and R. Hurst, "The Lightweight Online
	Certificate Status Protocol (OCSP) Profile for High-Volume		Certificate Status Protocol (OCSP) Profile for High-Volume
	Environments", RFC 5019, September 2007.		Environments", RFC 5019, DOI 10.17487/RFC5019, September
			2007, <http://www.rfc-editor.org/info/rfc5019>.
	[RFC5055] Freeman, T., Housley, R., Malpani, A., Cooper, D., and W.		[RFC5055] Freeman, T., Housley, R., Malpani, A., Cooper, D., and W.
	Polk, "Server-Based Certificate Validation Protocol		Polk, "Server-Based Certificate Validation Protocol
	(SCVP)", RFC 5055, December 2007.		(SCVP)", RFC 5055, DOI 10.17487/RFC5055, December 2007,
			<http://www.rfc-editor.org/info/rfc5055>.
	[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,		[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
	Housley, R., and W. Polk, "Internet X.509 Public Key		Housley, R., and W. Polk, "Internet X.509 Public Key
	Infrastructure Certificate and Certificate Revocation List		Infrastructure Certificate and Certificate Revocation List
	(CRL) Profile", RFC 5280, May 2008.		(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
			<http://www.rfc-editor.org/info/rfc5280>.
	[RFC5958] Turner, S., "Asymmetric Key Packages", RFC 5958, August		[RFC5958] Turner, S., "Asymmetric Key Packages", RFC 5958,
	2010.		DOI 10.17487/RFC5958, August 2010,
			<http://www.rfc-editor.org/info/rfc5958>.
	[RFC6919] Barnes, R., Kent, S., and E. Rescorla, "Further Key Words		[RFC6919] Barnes, R., Kent, S., and E. Rescorla, "Further Key Words
	for Use in RFCs to Indicate Requirement Levels", RFC 6919,		for Use in RFCs to Indicate Requirement Levels", RFC 6919,
	April 2013.		DOI 10.17487/RFC6919, April 2013,
			<http://www.rfc-editor.org/info/rfc6919>.
	[RFC6960] Santesson, S., Myers, M., Ankney, R., Malpani, A.,		[RFC6960] Santesson, S., Myers, M., Ankney, R., Malpani, A.,
	Galperin, S., and C. Adams, "X.509 Internet Public Key		Galperin, S., and C. Adams, "X.509 Internet Public Key
	Infrastructure Online Certificate Status Protocol - OCSP",		Infrastructure Online Certificate Status Protocol - OCSP",
	RFC 6960, June 2013.		RFC 6960, DOI 10.17487/RFC6960, June 2013,
			<http://www.rfc-editor.org/info/rfc6960>.
	[RFC7030] Pritikin, M., Yee, P., and D. Harkins, "Enrollment over		[RFC6961] Pettersen, Y., "The Transport Layer Security (TLS)
	Secure Transport", RFC 7030, October 2013.		Multiple Certificate Status Request Extension", RFC 6961,
			DOI 10.17487/RFC6961, June 2013,
			<http://www.rfc-editor.org/info/rfc6961>.
			[RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
			"Enrollment over Secure Transport", RFC 7030,
			DOI 10.17487/RFC7030, October 2013,
			<http://www.rfc-editor.org/info/rfc7030>.
	[RFC7299] Housley, R., "Object Identifier Registry for the PKIX		[RFC7299] Housley, R., "Object Identifier Registry for the PKIX
	Working Group", RFC 7299, July 2014.		Working Group", RFC 7299, DOI 10.17487/RFC7299, July 2014,
			<http://www.rfc-editor.org/info/rfc7299>.
	[X.680] USC/Information Sciences Institute, "Information		[X.680] USC/Information Sciences Institute, "Information
	Technology - Abstract Syntax Notation One.", ITU-T X.680,		Technology - Abstract Syntax Notation One.", ITU-T X.680,
	ISO/IEC 8824-1:2002, 2002.		ISO/IEC 8824-1:2002, 2002.
	[X.681] USC/Information Sciences Institute, "Information		[X.681] USC/Information Sciences Institute, "Information
	Technology - Abstract Syntax Notation One: Information		Technology - Abstract Syntax Notation One: Information
	Object Specification", ITU-T X.681, ISO/IEC 8824-2:2002,		Object Specification", ITU-T X.681, ISO/IEC 8824-2:2002,
	2002.		2002.
	skipping to change at page 15, line 9 ¶		skipping to change at page 17, line 49 ¶
	This appendix provides the normative ASN.1 [X.680] definitions for		This appendix provides the normative ASN.1 [X.680] definitions for
	the structures described in this specification using ASN.1, as		the structures described in this specification using ASN.1, as
	defined in [X.680] through [X.683].		defined in [X.680] through [X.683].
	TBD		TBD
	Authors' Addresses		Authors' Addresses
	Jon Peterson		Jon Peterson
	Neustar, Inc.		Neustar, Inc.
	1800 Sutter St Suite 570
	Concord, CA 94520
	US
	Email: jon.peterson@neustar.biz		Email: jon.peterson@neustar.biz
	Sean Turner		Sean Turner
	IECA, Inc.		Sn3rd
	3057 Nutley Street, Suite 106
	Farifax, VA 22031
	US
	Email: turners@ieca.com		Email: sean@sn3rd.com
End of changes. 66 change blocks.
	185 lines changed or deleted		312 lines changed or added
This html diff was produced by rfcdiff 1.48. The latest version is available from http://tools.ietf.org/tools/rfcdiff/