draft-ietf-dime-e2e-sec-req-05.txt		rfc7966.txt
	DIME H. Tschofenig		Internet Engineering Task Force (IETF) H. Tschofenig
	Internet-Draft ARM Limited		Request for Comments: 7966
	Intended status: Informational J. Korhonen, Ed.		Category: Informational J. Korhonen, Ed.
	Expires: December 10, 2016 Broadcom Limited		ISSN: 2070-1721 Broadcom Limited
	G. Zorn		G. Zorn
	Network Zen		Network Zen
	K. Pillay		K. Pillay
	Internet Solutions		Internet Solutions
	June 8, 2016		September 2016
	AVP Level Security for Non-neighboring Diameter Nodes: Scenarios and		Security at the Attribute-Value Pair (AVP) Level for
	Requirements		Non-neighboring Diameter Nodes: Scenarios and Requirements
	draft-ietf-dime-e2e-sec-req-05.txt
	Abstract		Abstract
	This specification specifies requirements for providing Diameter		This specification specifies requirements for providing Diameter
	security at the level of individual Attribute-Value Pairs.		security at the level of individual Attribute-Value Pairs (AVPs).
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This document is not an Internet Standards Track specification; it is
	provisions of BCP 78 and BCP 79.		published for informational purposes.
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	Copyright Notice		Copyright Notice
	Copyright (c) 2016 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.
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	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3		2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
	3. Security Threats . . . . . . . . . . . . . . . . . . . . . . 3		3. Security Threats . . . . . . . . . . . . . . . . . . . . . . 5
	4. Scenarios for Diameter AVP-Level Protection . . . . . . . . . 5		4. Scenarios for Diameter AVP-Level Protection . . . . . . . . . 7
	5. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 7		5. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 8
	6. Security Considerations . . . . . . . . . . . . . . . . . . . 8		6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
	7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8		7. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
	8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 8		7.1. Normative References . . . . . . . . . . . . . . . . . . 10
	9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9		7.2. Informative References . . . . . . . . . . . . . . . . . 10
	9.1. Normative References . . . . . . . . . . . . . . . . . . 9		Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 10
	9.2. Informative References . . . . . . . . . . . . . . . . . 9		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
	1. Introduction		1. Introduction
	The Diameter base protocol specification [2] defines security		The Diameter base protocol specification [2] defines security
	protection between neighboring Diameter peers. The Diameter mandates		protection between neighboring Diameter peers. Diameter mandates
	that peer connections must be protected by TLS (for TCP) [6], DTLS		that peer connections must be protected by Transport Layer Security
	(for SCTP) [7] or using security mechanisms that are independent of		(TLS) [6] for TCP, by Datagram TLS (DTLS) [7] for the Stream Control
	Diameter such as IPsec [5]. These security protocols offer a wide		Transmission Protocol (SCTP), or by security mechanisms that are
	range of security properties, including entity authentication, data-		independent of Diameter (such as IPsec [5]). These security
	origin authentication, integrity, confidentiality protection and		protocols offer a wide range of security properties, including entity
	replay protection. They also support a large number of cryptographic		authentication, data-origin authentication, integrity protection,
	algorithms, algorithm negotiation, and different types of		confidentiality protection, and replay protection. They also support
	credentials. It should be understood that TLS/DTLS/IPsec in Diameter		a large number of cryptographic algorithms, algorithm negotiation,
	context does not provide end-to-end security unless the Diameter		and different types of credentials. It should be understood that
	nodes are direct peers i.e., neighboring Diameter nodes. The current		TLS/DTLS/IPsec in the Diameter context does not provide end-to-end
	Diameter security is realized hop-by-hop.		security unless the Diameter nodes are direct peers, i.e.,
			neighboring Diameter nodes. The current Diameter security is
			realized hop by hop.
	The need to also offer additional security protection of Attribute		The need to also offer additional security protection of AVPs between
	Value Pairs (AVP) between non-neighboring Diameter nodes was		non-neighboring Diameter nodes was recognized very early in the work
	recognized very early in the work on Diameter. This led to work on		on Diameter. This led to work on Diameter security using the
	Diameter security using the Cryptographic Message Syntax (CMS) [3].		Cryptographic Message Syntax (CMS) [3]. However, due to the lack of
	Due to lack of deployment interest at that time (and the complexity		deployment interest at that time (and the complexity of the developed
	of the developed solution) the specification was, however, never		solution), the specification was never completed.
	completed.
	In the meanwhile Diameter had received a lot of deployment interest		In the meanwhile, Diameter had received a lot of deployment interest
	from the cellular operator community and because of the		from the cellular operator community, and because of the
	sophistication of those deployments the need for protecting Diameter		sophistication of those deployments, the need for protecting Diameter
	AVPs between non-neighboring nodes re-surfaced. Since early 2000		AVPs between non-neighboring nodes resurfaced. Since the early 2000s
	(when the work on [3] was discontinued) the Internet community had		(when the work on [3] was discontinued), the Internet community has
	seen advances in cryptographic algorithms (for example, authenticated		seen advances in cryptographic algorithms (for example, authenticated
	encryption algorithms) and new security building blocks were		encryption algorithms), and new security building blocks have been
	developed.		developed.
	This document specifies requirements for developing a solution to		This document specifies requirements for developing a solution to
	protect Diameter AVPs between non-neighboring Diameter nodes.		protect Diameter AVPs between non-neighboring Diameter nodes.
	2. Terminology		2. Terminology
	The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT',		The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT',
	'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and 'OPTIONAL' in this		'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and 'OPTIONAL' in this
	documents are to be interpreted as described in RFC 2119 [1].		document are to be interpreted as described in RFC 2119 [1].
	This document re-uses terminology from the Diameter base		This document reuses terminology from the Diameter base specification
	specification [2].		[2].
	In the figures below Attribute Value Pair (AVP) refers to an		In the figures below, AVP refers to an unprotected AVP, and {AVP}k
	unprotected AVP and {AVP}k refers to an AVP that experiences security		refers to an AVP that experiences security protection (using key "k")
	protection (using key "k") without further distinguishing between		without further distinguishing between integrity and confidentiality
	integrity and confidentiality protection.		protection.
	The following terms are also used in this document:		The following terms are also used in this document:
	AAA Broker		AAA broker
	An entity that manages AAA traffic between roaming partner		An entity that manages Authentication, Authorization, and
	networks.		Accounting (AAA) traffic between roaming partner networks.
	AAA Broker Network		AAA broker network
	A network operated by an AAA Broker, which consists of necessary		A network operated by a AAA broker, which consists of necessary
	AAA functions to provide AAA brokering services for its customer		AAA functions to provide AAA brokering services for its customer
	AAA networks.		AAA networks.
	Diameter Firewall		Diameter firewall
	A Diameter firewall is a proxy (or a relay) agent that acts		A Diameter firewall is a proxy (or a relay) agent that acts
	similarly to conventional IP traffic firewalls but only at the		similarly to conventional IP traffic firewalls but only at the
	Diameter AVP and command level. A Diameter firewall may, for		Diameter AVP and command level. A Diameter firewall may, for
	example, discard security policy offending AVPs from traversing		example, discard AVPs that violate security policy, thus
	through it. The Diameter firewall may even discard entire		preventing them from traversing the firewall. The Diameter
	Diameter messages based on the security policy.		firewall may even discard entire Diameter messages based on the
			security policy.
	3. Security Threats		3. Security Threats
	The following description aims to illustrate various security threats		This section describes various security threats that raise the need
	that raise the need for protecting Diameter Attribute-Value Pairs		for protecting Diameter Attribute-Value Pairs (AVPs). Figure 1
	(AVPs). Figure 1 illustrates an example of Diameter based roaming		illustrates an example of a Diameter-based roaming architecture in
	architecture in which Diameter clients within the visited networks		which Diameter clients within the visited networks need to interact
	need to interact with Diameter servers in the home domain. AAA		with Diameter servers in the home domain. AAA domains are
	domains are interconnected using a Diameter-based AAA interconnection		interconnected using a Diameter-based AAA interconnection network
	network labeled as AAA Broker.		labeled as "AAA broker network".
	+oooooooooooooooooo+ +====================+		+oooooooooooooooooo+ +====================+
	| Example.net | | |		| Example.net | | |
	| | | |		| | | |
	+--------+ +--------+ +--------+ +--------+		+--------+ +--------+ +--------+ +--------+
	|Diameter| |Diameter+--------+Diameter| |Diameter|		|Diameter| |Diameter+--------+Diameter| |Diameter|
	|Client 1| |Proxy A1| |Proxy B | |Proxy C |		|Client 1| |Proxy A1| |Proxy B | |Proxy C |
	| (NAS) +------+ | +------+ +--------+ |----+		| (NAS) +------+ | +------+ +--------+ |----+
	+--------+ +--------+ | +--------+ +--------+ |		+--------+ +--------+ | +--------+ +--------+ |
	| | | | | |		| | | | | |
	skipping to change at page 4, line 38 ¶		skipping to change at page 5, line 44 ¶
	| | | +--------+ +---------+Proxy D |-+		| | | +--------+ +---------+Proxy D |-+
	+--------+ +--------+ | |Diameter| | +--------+		+--------+ +--------+ | |Diameter| | +--------+
	|Diameter| |Diameter| | |Server Y+--+ |		|Diameter| |Diameter| | |Server Y+--+ |
	|Client 2+------+Proxy A2+-+ +--------+ Home Domain |		|Client 2+------+Proxy A2+-+ +--------+ Home Domain |
	| (NAS) | | | +////////////////////+		| (NAS) | | | +////////////////////+
	+--------+ +--------+		+--------+ +--------+
	| |		| |
	| Visited Domain 2 |		| Visited Domain 2 |
	+oooooooooooooooooo+		+oooooooooooooooooo+
	Figure 1: Example Diameter Deployment.		Figure 1: Example Diameter Deployment
	Eavesdropping: Some Diameter applications carry information that is		Eavesdropping: Some Diameter applications carry information that is
	only intended for consumption by end points, either by the		only intended for consumption by end points, either by the
	Diameter client or by the Diameter server but not by		Diameter client or by the Diameter server but not by
	intermediaries. As an example, consider the Diameter EAP		intermediaries. As an example, consider the Diameter Extensible
	application [4] that allows the transport of keying material		Authentication Protocol (EAP) application [4] that allows the
	between the Diameter server to the Diameter client (using the EAP-		transport of keying material between the Diameter server to the
	Master-Session-Key AVP) for the protection of the air interface		Diameter client (using the EAP-Master-Session-Key AVP) for the
	(i.e., the wireless link) between the end device (such as a mobile		protection of the air interface (i.e., the wireless link) between
	phone; not shown in the figure) and the Network Access Server		the end device (such as a mobile phone; not shown in the figure)
	(NAS). The content of the EAP-Master-Session-Key AVP should		and the Network Access Server (NAS). The content of the EAP-
	benefit from protection against eavesdropping by intermediaries.		Master-Session-Key AVP should benefit from protection against
	Other AVPs, for example those listed in Section 13.3 of [2], might		eavesdropping by intermediaries. Other AVPs (for example, those
	also carry sensitive personal data that, when collected by		listed in Section 13.3 of [2]) might also carry sensitive personal
	intermediaries, allow for traffic analysis.		data that, when collected by intermediaries, allow for traffic
			analysis.
	In context of the deployment shown in Figure 1 the adversary		In the context of the deployment shown in Figure 1, the adversary
	could, for example, be in the AAA broker network.		could, for example, be in the AAA broker network.
	Injection and Manipulation: The Diameter base protocol specification		Injection and Manipulation: The Diameter base protocol specification
	mandates security protection between neighboring nodes but		mandates security protection between neighboring nodes, but
	Diameter agents may be compromised or misconfigured and inject or		Diameter agents may be compromised or misconfigured and inject or
	manipulate AVPs. To detect such actions additional security		manipulate AVPs. To detect such actions, additional security
	protection needs to be applied at the Diameter layer.		protection needs to be applied at the Diameter layer.
	Nodes that could launch such an attack are any Diameter agents		Nodes that could launch such an attack are any Diameter agents
	along the end-to-end communication path.		along the end-to-end communication path.
	Impersonation: Imagine a case where a Diameter message from		Impersonation: Imagine a case where a Diameter message from
	Example.net contains information claiming to be from Example.org.		Example.net contains information claiming to be from Example.org.
	This would either require strict verification at the edge of the		This would either require strict verification at the edge of the
	AAA broker network or cryptographic assurance at the Diameter		AAA broker network or cryptographic assurance at the Diameter
	layer to prevent a successful impersonation attack.		layer to prevent a successful impersonation attack.
	skipping to change at page 5, line 38 ¶		skipping to change at page 7, line 13 ¶
	financial benefits or to disrupt service availability.		financial benefits or to disrupt service availability.
	4. Scenarios for Diameter AVP-Level Protection		4. Scenarios for Diameter AVP-Level Protection
	This scenario outlines a number of cases for deploying security		This scenario outlines a number of cases for deploying security
	protection of individual Diameter AVPs.		protection of individual Diameter AVPs.
	In the first scenario, shown in Figure 2, end-to-end security		In the first scenario, shown in Figure 2, end-to-end security
	protection is provided between the Diameter client and the Diameter		protection is provided between the Diameter client and the Diameter
	server with any number of intermediate Diameter agents. Diameter		server with any number of intermediate Diameter agents. Diameter
	AVPs exchanged between these two Diameter nodes may be protected end-		AVPs exchanged between these two Diameter nodes may be protected end
	to-end (notation '{AVP}k') or unprotected (notation 'AVP').		to end (notation '{AVP}k') or unprotected (notation 'AVP').
	+--------+ +--------+		+--------+ +--------+
	|Diameter| AVP, {AVP}k |Diameter|		|Diameter| AVP, {AVP}k |Diameter|
	|Client +-----------------........... -------------------+Server |		|Client +-----------------........... -------------------+Server |
	+--------+ +--------+		+--------+ +--------+
	Figure 2: End-to-End Diameter AVP Security Protection.		Figure 2: End-to-End Diameter AVP Security Protection
	In the second scenario, shown in Figure 3, a Diameter proxy acts on		In the second scenario, shown in Figure 3, a Diameter proxy acts on
	behalf of the Diameter client with regard to security protection. It		behalf of the Diameter client with regard to security protection. It
	applies security protection to outgoing Diameter AVPs and verifies		applies security protection to outgoing Diameter AVPs and verifies
	incoming AVPs. Typically, the proxy enforcing the security		incoming AVPs. Typically, the proxy enforcing the security
	protection belongs to the same domain as the Diameter client/server		protection belongs to the same domain as the Diameter client/server
	without end-to-end security features.		without end-to-end security features.
	+--------+ +--------+ +--------+		+--------+ +--------+ +--------+
	|Diameter| AVP |Diameter| AVP, {AVP}k |Diameter|		|Diameter| AVP |Diameter| AVP, {AVP}k |Diameter|
	|Client +-----+Proxy A +---------- .......... -----------+Server |		|Client +-----+Proxy A +---------- .......... -----------+Server |
	+--------+ +--------+ +--------+		+--------+ +--------+ +--------+
	Figure 3: Middle-to-End Diameter AVP Security Protection.		Figure 3: Middle-to-End Diameter AVP Security Protection
	In the third scenario shown in Figure 4 a Diameter proxy acts on		In the third scenario, shown in Figure 4, a Diameter proxy acts on
	behalf of the Diameter server.		behalf of the Diameter server.
	+--------+ +--------+ +--------+		+--------+ +--------+ +--------+
	|Diameter| AVP, {AVP}k |Diameter| AVP |Diameter|		|Diameter| AVP, {AVP}k |Diameter| AVP |Diameter|
	|Client +-----------------........... ----+Proxy D +-----+Server |		|Client +-----------------........... ----+Proxy D +-----+Server |
	+--------+ +--------+ +--------+		+--------+ +--------+ +--------+
	Figure 4: End-to-Middle Diameter AVP Security Protection.		Figure 4: End-to-Middle Diameter AVP Security Protection
	The fourth and the final scenario (see Figure 5) is a combination of		The fourth and the final scenario (see Figure 5) is a combination of
	the end-to-middle and the middle-to-end scenario shown in Figure 4		the middle-to-end and the end-to-middle scenarios shown in Figures 3
	and in Figure 3. From a deployment point of view this scenario is		and 4. From a deployment point of view, this scenario is easier to
	easier to accomplish for two reasons: First, Diameter clients and		accomplish for two reasons. First, Diameter clients and Diameter
	Diameter servers remain unmodified. This ensures that no		servers remain unmodified. This ensures that no modifications are
	modifications are needed to the installed Diameter infrastructure,		needed to the installed Diameter infrastructure, except for the
	except for the security enabled proxies obviously. Second, the key		security-enabled proxies, obviously. Second, the key management is
	management is also simplified since fewer number of keys need to be		also simplified since a fewer number of keys need to be negotiated
	negotiated and provisioned. The assumption here is that the number		and provisioned. The assumption here is that the number of security-
	of security enabled proxies would be significantly less than		enabled proxies would be significantly less than unprotected Diameter
	unprotected Diameter nodes in the installed base.		nodes in the installed base.
	+--------+ +--------+ +--------+ +--------+		+--------+ +--------+ +--------+ +--------+
	|Diameter| AVP |Diameter| AVP, {AVP}k |Diameter| AVP |Diameter|		|Diameter| AVP |Diameter| AVP, {AVP}k |Diameter| AVP |Diameter|
	|Client +-----+Proxy A +-- .......... ----+Proxy D +-----+Server |		|Client +-----+Proxy A +-- .......... ----+Proxy D +-----+Server |
	+--------+ +--------+ +--------+ +--------+		+--------+ +--------+ +--------+ +--------+
	Figure 5: Middle-to-Middle Diameter AVP Security Protection.		Figure 5: Middle-to-Middle Diameter AVP Security Protection
	5. Requirements		5. Requirements
	Requirement #1: The solution MUST support an extensible set of		Requirement #1: The solution MUST support an extensible set of
	cryptographic algorithms.		cryptographic algorithms.
	Motivation: Solutions MUST be able to evolve to adapt to		Motivation: Solutions MUST be able to evolve to adapt to
	evolving cryptographic algorithms and security requirements.		evolving cryptographic algorithms and security requirements.
	This may include the provision of a modular mechanism to allow		This may include the provision of a modular mechanism to allow
	cryptographic algorithms to be updated without substantial		cryptographic algorithms to be updated without substantial
	skipping to change at page 7, line 25 ¶		skipping to change at page 8, line 37 ¶
	Requirement #2: The solution MUST support confidentiality,		Requirement #2: The solution MUST support confidentiality,
	integrity, and data-origin authentication. Solutions for		integrity, and data-origin authentication. Solutions for
	integrity protection MUST work in a backwards-compatible way with		integrity protection MUST work in a backwards-compatible way with
	existing Diameter applications and therefore be able to traverse		existing Diameter applications and therefore be able to traverse
	legacy proxy and relay agents.		legacy proxy and relay agents.
	Requirement #3: The solution MUST support replay protection.		Requirement #3: The solution MUST support replay protection.
	Requirement #4: The solution MUST support the ability to delegate		Requirement #4: The solution MUST support the ability to delegate
	security functionality to another entity		security functionality to another entity.
	Motivation: As described in Section 4 the ability to let a		Motivation: As described in Section 4, the ability to let a
	Diameter proxy to perform security services on behalf of all		Diameter proxy perform security services on behalf of all
	clients within the same administrative domain is important for		clients within the same administrative domain is important for
	incremental deployability. The same applies to the other		incremental deployability. The same applies to the other
	communication side where a load balancer terminates security		communication side where a load balancer terminates security
	services for the servers it interfaces.		services for the servers it interfaces.
	Requirement #5: The solution MUST be able to selectively apply their		Requirement #5: The solution MUST be able to selectively apply its
	cryptographic protection to certain Diameter AVPs.		cryptographic protection to certain Diameter AVPs.
	Motivation: Some Diameter applications assume that certain AVPs		Motivation: Some Diameter applications assume that certain AVPs
	are added, removed, or modified by intermediaries. As such, it		are added, removed, or modified by intermediaries. As such, it
	must be possible to apply security protection selectively.		must be possible to apply security protection selectively.
	Furthermore, there are AVPs that must not be confidentiality		Furthermore, there are AVPs that must not be confidentiality
	protected but may still be integrity protected such as those		protected but may still be integrity protected, such as those
	required for Diameter message routing.		required for Diameter message routing.
	Requirement #6: The solution MUST define a mandatory-to-implement		Requirement #6: The solution MUST define a mandatory-to-implement
	cryptographic algorithm.		cryptographic algorithm.
	Motivation: For interoperability purposes it is beneficial to		Motivation: For interoperability purposes, it is beneficial to
	have a mandatory-to-implement cryptographic algorithm specified		have a mandatory-to-implement cryptographic algorithm specified
	(unless profiles for specific usage environments specify		(unless profiles for specific usage environments specify
	otherwise).		otherwise).
	Requirement #7: The solution MUST support symmetric keys and		Requirement #7: The solution MUST support symmetric keys and
	asymmetric keys.		asymmetric keys.
	Motivation: Symmetric and asymmetric cryptographic algorithms		Motivation: Symmetric and asymmetric cryptographic algorithms
	provide different security services. Asymmetric algorithms,		provide different security services. Asymmetric algorithms,
	for example, allow non-repudiation services to be offered.		for example, allow non-repudiation services to be offered.
	Requirement #8: A solution for dynamic key management MUST be		Requirement #8: A solution for dynamic key management MUST be
	included in the overall solution framework.		included in the overall solution framework.
	However, it is assumed that no "new" key management protocol		However, it is assumed that no "new" key management protocol
	needs to be developed; instead existing ones are re-used, if at		needs to be developed; instead, existing ones are reused, if at
	all possible. Rekeying could be triggered by (a) management		all possible. Rekeying could be triggered by (a) management
	actions and (b) expiring keying material.		actions and (b) expiring keying material.
	6. Security Considerations		6. Security Considerations
	This entire document focused on the discussion of new functionality		This entire document focuses on the discussion of new functionality
	for securing Diameter AVPs selectively between non-neighboring nodes.		for securing Diameter AVPs selectively between non-neighboring nodes.
	Various security threats are mitigated by selectively applying		Various security threats are mitigated by selectively applying
	security protection for individual Diameter AVPs. Without protection		security protection for individual Diameter AVPs. Without
	there is the possibility for password sniffing, confidentiality		protection, there is the possibility for password sniffing,
	violation, AVP insertion, deletion or modification. Additionally,		confidentiality violation, and AVP insertion, deletion, or
	applying digital signature offers non-repudiation capabilities; a		modification. Additionally, applying a digital signature offers non-
	feature not yet available in today's Diameter deployment.		repudiation capabilities, a feature not yet available in today's
	Modification of certain Diameter AVPs may not necessarily be the act		Diameter deployment. Modification of certain Diameter AVPs may not
	of malicious behavior but could also be the result of		necessarily be the act of malicious behavior but could also be the
	misconfiguration. An over-aggressively configured firewalling		result of misconfiguration. An over-aggressively configured
	Diameter proxy may also remove certain AVPs. In most cases data		firewalling Diameter proxy may also remove certain AVPs. In most
	origin authentication and integrity protection of AVPs will provide		cases, data-origin authentication and integrity protection of AVPs
	the most benefits for existing deployments with minimal overhead and		will provide the most benefits for existing deployments with minimal
	(potentially) operating in a full-backwards compatible manner.		overhead and (potentially) operate in a full-backwards compatible
			manner.
	7. IANA Considerations
	This document does not require actions by IANA.
	8. Acknowledgments
	We would like to thank Guenther Horn, Martin Dolly, Steve Donovan,
	Lionel Morand and Tom Taylor (rest in peace Tom) for their review
	comments.
	The authors also thank Qin Wu, Christer Holmberg, Ben Campbell and
	Radia Perlman who provided additional reviews during the Last Call.
	9. References		7. References
	9.1. Normative References		7.1. Normative References
	[1] Bradner, S., "Key words for use in RFCs to Indicate		[1] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<http://www.rfc-editor.org/info/rfc2119>.		<http://www.rfc-editor.org/info/rfc2119>.
	[2] Fajardo, V., Ed., Arkko, J., Loughney, J., and G. Zorn,		[2] Fajardo, V., Ed., Arkko, J., Loughney, J., and G. Zorn,
	Ed., "Diameter Base Protocol", RFC 6733,		Ed., "Diameter Base Protocol", RFC 6733,
	DOI 10.17487/RFC6733, October 2012,		DOI 10.17487/RFC6733, October 2012,
	<http://www.rfc-editor.org/info/rfc6733>.		<http://www.rfc-editor.org/info/rfc6733>.
	9.2. Informative References		7.2. Informative References
	[3] Calhoun, P., Farrell, S., and W. Bulley, "Diameter CMS		[3] Calhoun, P., Farrell, S., and W. Bulley, "Diameter CMS
	Security Application", draft-ietf-aaa-diameter-cms-sec-04		Security Application", Work in Progress,
	(work in progress), March 2002.		draft-ietf-aaa-diameter-cms-sec-04, March 2002.
	[4] Eronen, P., Ed., Hiller, T., and G. Zorn, "Diameter		[4] Eronen, P., Ed., Hiller, T., and G. Zorn, "Diameter
	Extensible Authentication Protocol (EAP) Application",		Extensible Authentication Protocol (EAP) Application",
	RFC 4072, DOI 10.17487/RFC4072, August 2005,		RFC 4072, DOI 10.17487/RFC4072, August 2005,
	<http://www.rfc-editor.org/info/rfc4072>.		<http://www.rfc-editor.org/info/rfc4072>.
	[5] Kent, S. and K. Seo, "Security Architecture for the		[5] Kent, S. and K. Seo, "Security Architecture for the
	Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,		Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
	December 2005, <http://www.rfc-editor.org/info/rfc4301>.		December 2005, <http://www.rfc-editor.org/info/rfc4301>.
	skipping to change at page 9, line 45 ¶		skipping to change at page 10, line 45 ¶
	(TLS) Protocol Version 1.2", RFC 5246,		(TLS) Protocol Version 1.2", RFC 5246,
	DOI 10.17487/RFC5246, August 2008,		DOI 10.17487/RFC5246, August 2008,
	<http://www.rfc-editor.org/info/rfc5246>.		<http://www.rfc-editor.org/info/rfc5246>.
	[7] Tuexen, M., Seggelmann, R., and E. Rescorla, "Datagram		[7] Tuexen, M., Seggelmann, R., and E. Rescorla, "Datagram
	Transport Layer Security (DTLS) for Stream Control		Transport Layer Security (DTLS) for Stream Control
	Transmission Protocol (SCTP)", RFC 6083,		Transmission Protocol (SCTP)", RFC 6083,
	DOI 10.17487/RFC6083, January 2011,		DOI 10.17487/RFC6083, January 2011,
	<http://www.rfc-editor.org/info/rfc6083>.		<http://www.rfc-editor.org/info/rfc6083>.
			Acknowledgments
			We would like to thank Guenther Horn, Martin Dolly, Steve Donovan,
			Lionel Morand, and Tom Taylor (rest in peace, Tom) for their review
			comments.
			The authors also thank Qin Wu, Christer Holmberg, Ben Campbell, and
			Radia Perlman, who provided additional reviews during the Last Call.
	Authors' Addresses		Authors' Addresses
	Hannes Tschofenig		Hannes Tschofenig
	ARM Limited		Hall in Tirol 6060
	Austria		Austria
	Email: Hannes.tschofenig@gmx.net		Email: Hannes.tschofenig@gmx.net
	URI: http://www.tschofenig.priv.at		URI: http://www.tschofenig.priv.at
	Jouni Korhonen (editor)		Jouni Korhonen (editor)
	Broadcom Limited		Broadcom Limited
	3151 Zanker Rd.		3151 Zanker Rd.
	San Jose, CA 95134		San Jose, CA 95134
	USA		United States of America
	Email: jouni.nospam@gmail.com		Email: jouni.nospam@gmail.com
	Glen Zorn		Glen Zorn
	Network Zen		Network Zen
	227/358 Thanon Sanphawut		227/358 Thanon Sanphawut
	Bang Na Bangkok 10260		Bang Na, Bangkok 10260
	Thailand		Thailand
	Email: glenzorn@gmail.com		Email: glenzorn@gmail.com
	Kervin Pillay		Kervin Pillay
	Internet Solutions		Internet Solutions
	South Africa		South Africa
	Email: kervin.pillay@gmail.com		Email: kervin.pillay@gmail.com
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