< draft-ietf-uta-xmpp-05.txt		draft-ietf-uta-xmpp-06.txt >
	Network Working Group P. Saint-Andre		Network Working Group P. Saint-Andre
	Internet-Draft &yet		Internet-Draft &yet
	Updates: 6120 (if approved) T. Alkemade		Updates: 6120 (if approved) T. Alkemade
	Intended status: Standards Track		Intended status: Standards Track
	Expires: July 27, 2015 January 23, 2015		Expires: October 16, 2015 April 14, 2015
	Use of Transport Layer Security (TLS) in the Extensible Messaging and		Use of Transport Layer Security (TLS) in the Extensible Messaging and
	Presence Protocol (XMPP)		Presence Protocol (XMPP)
	draft-ietf-uta-xmpp-05		draft-ietf-uta-xmpp-06
	Abstract		Abstract
	This document provides recommendations for the use of Transport Layer		This document provides recommendations for the use of Transport Layer
	Security (TLS) in the Extensible Messaging and Presence Protocol		Security (TLS) in the Extensible Messaging and Presence Protocol
	(XMPP). This document updates RFC 6120.		(XMPP). This document updates RFC 6120.
	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
	skipping to change at page 1, line 34 ¶		skipping to change at page 1, line 34 ¶
	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 July 27, 2015.		This Internet-Draft will expire on October 16, 2015.
	Copyright Notice		Copyright Notice
	Copyright (c) 2015 IETF Trust and the persons identified as the		Copyright (c) 2015 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
	skipping to change at page 2, line 14 ¶		skipping to change at page 2, line 14 ¶
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2		2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
	3. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 3		3. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 3
	3.1. Support for TLS . . . . . . . . . . . . . . . . . . . . . 3		3.1. Support for TLS . . . . . . . . . . . . . . . . . . . . . 3
	3.2. Compression . . . . . . . . . . . . . . . . . . . . . . . 3		3.2. Compression . . . . . . . . . . . . . . . . . . . . . . . 3
	3.3. Session Resumption . . . . . . . . . . . . . . . . . . . 3		3.3. Session Resumption . . . . . . . . . . . . . . . . . . . 3
	3.4. Authenticated Connections . . . . . . . . . . . . . . . . 3		3.4. Authenticated Connections . . . . . . . . . . . . . . . . 3
	3.5. Unauthenticated Connections . . . . . . . . . . . . . . . 4		3.5. Server Name Indication . . . . . . . . . . . . . . . . . 4
	3.6. Server Name Indication . . . . . . . . . . . . . . . . . 4		3.6. Human Factors . . . . . . . . . . . . . . . . . . . . . . 5
	3.7. Human Factors . . . . . . . . . . . . . . . . . . . . . . 4
	4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5		4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
	5. Security Considerations . . . . . . . . . . . . . . . . . . . 5		5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
	6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5		6. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
	6.1. Normative References . . . . . . . . . . . . . . . . . . 5		6.1. Normative References . . . . . . . . . . . . . . . . . . 6
	6.2. Informative References . . . . . . . . . . . . . . . . . 6		6.2. Informative References . . . . . . . . . . . . . . . . . 6
	Appendix A. Implementation Notes . . . . . . . . . . . . . . . . 7		Appendix A. Implementation Notes . . . . . . . . . . . . . . . . 8
	Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 7		Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 8
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
	1. Introduction		1. Introduction
	The Extensible Messaging and Presence Protocol (XMPP) [RFC6120]		The Extensible Messaging and Presence Protocol (XMPP) [RFC6120]
	(along with its precursor, the so-called "Jabber protocol") has used		(along with its precursor, the so-called "Jabber protocol") has used
	Transport Layer Security (TLS) [RFC5246] (along with its precursor,		Transport Layer Security (TLS) [RFC5246] (along with its precursor,
	Secure Sockets Layer or SSL) since 1999. Both [RFC6120] and its		Secure Sockets Layer or SSL) since 1999. Both [RFC6120] and its
	predecessor [RFC3920] provided recommendations regarding the use of		predecessor [RFC3920] provided recommendations regarding the use of
	TLS in XMPP. In order to address the evolving threat model on the		TLS in XMPP. In order to address the evolving threat model on the
	Internet today, this document provides stronger recommendations.		Internet today, this document provides stronger recommendations.
	NOTE: Unless explicitly noted otherwise, all of the		In particular, this document updates [RFC6120] by specifying that
	recommendations specified in [I-D.ietf-uta-tls-bcp] apply to XMPP.		XMPP implementations and deployments MUST follow the best current
	In the main, this document merely provides supplementary		practices documented in the "Recommendations for Secure Use of TLS
	information; those who implement and deploy XMPP technologies are		and DTLS" [I-D.ietf-uta-tls-bcp]. This includes stronger
	expected to follow the recommendations of [I-D.ietf-uta-tls-bcp].		recommendations regarding SSL/TLS protocol versions, fallback to
			lower versions, TLS-layer compression, TLS session resumption, cipher
	This document updates [RFC6120].		suites, public key lengths, forward secrecy, and other aspects of
			using TLS with XMPP.
	2. Terminology		2. Terminology
	Various security-related terms are to be understood in the sense		Various security-related terms are to be understood in the sense
	defined in [RFC4949].		defined in [RFC4949].
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and		"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
	"OPTIONAL" in this document are to be interpreted as described in		"OPTIONAL" in this document are to be interpreted as described in
	[RFC2119].		[RFC2119].
	3. Recommendations		3. Recommendations
			The best current practices documented in the "Recommendations for
			Secure Use of TLS and DTLS" [I-D.ietf-uta-tls-bcp] are included here
			by reference. Instead of repeating those recommendations here, this
			document mostly provides supplementary information regarding secure
			implementation and deployment of XMPP technologies.
	3.1. Support for TLS		3.1. Support for TLS
	Support for TLS (specifically, the XMPP profile of STARTTLS) is		Support for TLS (specifically, the XMPP profile of STARTTLS) is
	mandatory for XMPP implementations, as already specified in [RFC6120]		mandatory for XMPP implementations, as already specified in [RFC6120]
	and its predecessor [RFC3920].		and its predecessor [RFC3920].
	The server (i.e., the XMPP receiving entity) to which a client or		The server (i.e., the XMPP receiving entity) to which a client or
	peer server (i.e., the XMPP initiating entity) connects might not		peer server (i.e., the XMPP initiating entity) connects might not
	offer a stream feature of <starttls xmlns='urn:ietf:params:xml:ns		offer a stream feature of <starttls xmlns='urn:ietf:params:xml:ns
	:xmpp-tls'/>. Although in general this stream feature indicates that		:xmpp-tls'/>. Although in general this stream feature indicates that
	the server supports XMPP 1.0 and therefore supports TLS, it is		the server supports XMPP 1.0 and therefore supports TLS, that this
	possible that this stream feature might be stripped out by an		stream feature might be stripped out by an attacker (see Section 2.1
	attacker (see Section 2.1 of [I-D.ietf-uta-tls-attacks]). Therefore,		of [RFC7457]). Similarly, the <required/> child element of the
	the initiating entity SHOULD proceed with the stream negotiation even		<starttls/> stream feature is used to indicate that negotiation of
	if the receiving entity does not advertise support for TLS.		TLS is mandatory, but could also be stripped out by an attacker.
	Similarly, although a receiving entity SHOULD include the <required/>		Therefore, the initiating entity MUST NOT be deterred from attempting
	child element to indicate that negotiation of TLS is mandatory, an		TLS negotiation even if the receiving entity does not advertise
	initiating entity MUST NOT depend on receiving the <required/> flag		support for TLS. Instead, the initiating entity SHOULD (based on
	in determining whether TLS will be enforced for the stream.		local policy) proceed with the stream negotiation and attempt to
			negotiate TLS.
	3.2. Compression		3.2. Compression
	XMPP supports an application-layer compression technology [XEP-0138].		XMPP supports an application-layer compression technology [XEP-0138].
	Although this XMPP extension might have slightly stronger security		Although this XMPP extension might have slightly stronger security
	properties than TLS-layer compression (since it is enabled after SASL		properties than TLS-layer compression (since it is enabled after SASL
	authentication, as described in [XEP-0170]), this document neither		authentication, as described in [XEP-0170]), this document neither
	encourages nor discourages use of XMPP-layer compression.		encourages nor discourages use of XMPP-layer compression.
	3.3. Session Resumption		3.3. Session Resumption
	In XMPP, TLS session resumption can be used in concert with the XMPP		In XMPP, TLS session resumption can be used in concert with the XMPP
	Stream Management extension; see [XEP-0198] for further details.		Stream Management extension; see [XEP-0198] for further details.
	3.4. Authenticated Connections		3.4. Authenticated Connections
	Both the core XMPP specification [RFC6120] and the "CertID"		Both the core XMPP specification [RFC6120] and the "CertID"
	specification [RFC6125] provide recommendations and requirements for		specification [RFC6125] provide recommendations and requirements for
	certificate validation in the context of authenticated connections.		certificate validation in the context of authenticated connections.
	This document does not supersede those specifications. Wherever		This document does not supersede those specifications (e.g., it does
	possible, it is best to prefer authenticated connections (along with		not modify the recommendations in [RFC6120] regarding the Subject
	SASL [RFC4422]), as already stated in the core XMPP specification		Alternative Names or other certificate details that need to be
	[RFC6120]. In particular, clients MUST authenticate servers and		supported for authentication of XMPP connections using PKIX
	servers MUST authenticate clients. This document does not mandate		certificates).
	that servers need to authenticate peer servers (see next section).
	This document does not modify the recommendations in [RFC6120]
	regarding the Subject Alternative Names (or other certificate
	details) that need to be supported for authentication of XMPP
	connections using PKIX certificates.
	The Domain Name Associations (DNA) specification [I-D.ietf-xmpp-dna]		Wherever possible, it is best to prefer authenticated connections
	describes a framework for XMPP server authentication methods, which		(along with SASL [RFC4422]), as already stated in the core XMPP
	include not only PKIX but also DNS-Based Authentication of Named		specification [RFC6120]. In particular, clients MUST authenticate
	Entities (DANE) as defined in [I-D.ietf-dane-srv] and PKIX over		servers and servers MUST authenticate clients.
	Secure HTTP (POSH) as defined in [I-D.ietf-xmpp-posh].
	3.5. Unauthenticated Connections		This document does not mandate that servers need to authenticate peer
			servers, although such authentication is strongly preferred and
			servers SHOULD authenticate each other. Unfortunately, in multi-
			tenanted environments it can be extremely difficult to obtain and
			deploy PKIX certificates with the proper Subject Alternative Names
			(see [I-D.ietf-xmpp-dna] and [I-D.ietf-xmpp-posh] for details). To
			overcome that difficulty, the Domain Name Associations (DNA)
			specification [I-D.ietf-xmpp-dna] describes a framework for XMPP
			server authentication methods, which include not only PKIX but also
			DNS-Based Authentication of Named Entities (DANE) as defined in
			[I-D.ietf-dane-srv] and PKIX over Secure HTTP (POSH) as defined in
			[I-D.ietf-xmpp-posh]. These methods can provide a basis for server
			identity verification when appropriate PKIX certificates cannot be
			obtained and deployed.
	Given the pervasiveness of passive eavesdropping, even an		Given the pervasiveness of eavesdropping [RFC7258], even an
	unauthenticated connection might be better than an unencrypted		unauthenticated connection might be better than an unencrypted
	connection (this is similar to the "better than nothing security"		connection in these scenarios (this is similar to the "better than
	approach for IPsec [RFC5386]). Unauthenticated connections include		nothing security" approach for IPsec [RFC5386]). Unauthenticated
	connections negotiated using anonymous Diffie-Hellman algorithms or		connections include connections negotiated using anonymous Diffie-
	using self-signed certificates, among other scenarios. In		Hellman mechanisms or using self-signed certificates, among others.
	particular, because of current deployment challenges for		In particular for XMPP server-to-server interactions, it can be
	authenticated connections between XMPP servers (see
	[I-D.ietf-xmpp-dna] and [I-D.ietf-xmpp-posh] for details), it can be
	reasonable for XMPP server implementations to accept unauthenticated		reasonable for XMPP server implementations to accept unauthenticated
	connections when Server Dialback keys [XEP-0220] are used; although		but encrypted connections when Server Dialback keys [XEP-0220] are
	such keys on their own provide only weak identity verification (made		used; such keys on their own provide only weak identity verification
	stronger through the use of DNSSEC [RFC4033]), this at least enables		(made stronger through the use of DNSSEC [RFC4033]), but this at
	encryption of server-to-server connections.		least enables encryption of server-to-server connections. The DNA
			prooftypes described above are intended to mitigate the residual need
			for unauthenticated connections in these scenarios.
	3.6. Server Name Indication		3.5. Server Name Indication
	Although there is no harm in supporting the TLS Server Name		Although there is no harm in supporting the TLS Server Name
	Indication (SNI) extension [RFC6066], this is not necessary since the		Indication (SNI) extension [RFC6066], this is not necessary since the
	same function is served in XMPP by the 'to' address of the initial		same function is served in XMPP by the 'to' address of the initial
	stream header as explained in Section 4.7.2 of [RFC6120].		stream header as explained in Section 4.7.2 of [RFC6120].
	3.7. Human Factors		3.6. Human Factors
	It is strongly encouraged that XMPP clients provide ways for end		It is strongly encouraged that XMPP clients provide ways for end
	users (and that XMPP servers provide ways for administrators) to		users (and that XMPP servers provide ways for administrators) to
	complete the following tasks:		complete the following tasks:
	o Determine if a client-to-server or server-to-server connection is		o Determine if a given incoming or outgoing XML stream is encrypted
	encrypted and authenticated.		using TLS.
	o Determine the version of TLS used for a client-to-server or		o Determine the version of TLS used for encryption of a given
	server-to-server connection.		stream.
			o If authenticated encryption is used, determine how the connection
			was authenticated or verified (e.g., via PKI, DANE, POSH, or
			Server Dialback).
	o Inspect the certificate offered by an XMPP server.		o Inspect the certificate offered by an XMPP server.
	o Determine the cipher suite used to encrypt a connection.		o Determine the cipher suite used to encrypt a connection.
	o Be warned if the certificate changes for a given server.		o Be warned if the certificate changes for a given server.
	4. IANA Considerations		4. IANA Considerations
	This document requests no actions of the IANA.		This document requests no actions of the IANA.
	skipping to change at page 5, line 41 ¶		skipping to change at page 6, line 10 ¶
	compromised, leaving users utterly at the mercy of an adversary.		compromised, leaving users utterly at the mercy of an adversary.
	This document and related actions to strengthen the security of the		This document and related actions to strengthen the security of the
	XMPP network are based on the assumption that XMPP servers and		XMPP network are based on the assumption that XMPP servers and
	clients have not been subject to widespread compromise. If this		clients have not been subject to widespread compromise. If this
	assumption is valid, then ubiquitous use of per-hop TLS channel		assumption is valid, then ubiquitous use of per-hop TLS channel
	encryption and more significant deployment of end-to-end object		encryption and more significant deployment of end-to-end object
	encryption technologies will serve to protect XMPP communications to		encryption technologies will serve to protect XMPP communications to
	a measurable degree, compared to the alternatives.		a measurable degree, compared to the alternatives.
			This document covers only communication over the XMPP network and
			does not take into account gateways to non-XMPP networks. As an
			example, for security considerations related to gateways between XMPP
			and the Session Initiation Protocol (SIP) see [RFC7247] and
			[I-D.ietf-stox-im].
	6. References		6. References
	6.1. Normative References		6.1. Normative References
	[I-D.ietf-uta-tls-bcp]		[I-D.ietf-uta-tls-bcp]
	Sheffer, Y., Holz, R., and P. Saint-Andre,		Sheffer, Y., Holz, R., and P. Saint-Andre,
	"Recommendations for Secure Use of TLS and DTLS", draft-		"Recommendations for Secure Use of TLS and DTLS", draft-
	ietf-uta-tls-bcp-08 (work in progress), December 2014.		ietf-uta-tls-bcp-11 (work in progress), February 2015.
	[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, March 1997.
	[RFC4949] Shirey, R., "Internet Security Glossary, Version 2", RFC		[RFC4949] Shirey, R., "Internet Security Glossary, Version 2", RFC
	4949, August 2007.		4949, August 2007.
	[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security		[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
	(TLS) Protocol Version 1.2", RFC 5246, August 2008.		(TLS) Protocol Version 1.2", RFC 5246, August 2008.
	skipping to change at page 6, line 25 ¶		skipping to change at page 6, line 48 ¶
	Verification of Domain-Based Application Service Identity		Verification of Domain-Based Application Service Identity
	within Internet Public Key Infrastructure Using X.509		within Internet Public Key Infrastructure Using X.509
	(PKIX) Certificates in the Context of Transport Layer		(PKIX) Certificates in the Context of Transport Layer
	Security (TLS)", RFC 6125, March 2011.		Security (TLS)", RFC 6125, March 2011.
	6.2. Informative References		6.2. Informative References
	[I-D.ietf-dane-srv]		[I-D.ietf-dane-srv]
	Finch, T., Miller, M., and P. Saint-Andre, "Using DNS-		Finch, T., Miller, M., and P. Saint-Andre, "Using DNS-
	Based Authentication of Named Entities (DANE) TLSA records		Based Authentication of Named Entities (DANE) TLSA records
	with SRV and MX records.", draft-ietf-dane-srv-08 (work in		with SRV and MX records.", draft-ietf-dane-srv-12 (work in
	progress), October 2014.		progress), March 2015.
	[I-D.ietf-uta-tls-attacks]		[I-D.ietf-stox-im]
	Sheffer, Y., Holz, R., and P. Saint-Andre, "Summarizing		Saint-Andre, P., Houri, A., and J. Hildebrand,
	Current Attacks on TLS and DTLS", draft-ietf-uta-tls-		"Interworking between the Session Initiation Protocol
	attacks-05 (work in progress), October 2014.		(SIP) and the Extensible Messaging and Presence Protocol
			(XMPP): Instant Messaging", draft-ietf-stox-im-13 (work in
			progress), March 2015.
	[I-D.ietf-xmpp-dna]		[I-D.ietf-xmpp-dna]
	Saint-Andre, P. and M. Miller, "Domain Name Associations		Saint-Andre, P. and M. Miller, "Domain Name Associations
	(DNA) in the Extensible Messaging and Presence Protocol		(DNA) in the Extensible Messaging and Presence Protocol
	(XMPP)", draft-ietf-xmpp-dna-08 (work in progress),		(XMPP)", draft-ietf-xmpp-dna-10 (work in progress), March
	October 2014.		2015.
	[I-D.ietf-xmpp-posh]		[I-D.ietf-xmpp-posh]
	Miller, M. and P. Saint-Andre, "PKIX over Secure HTTP		Miller, M. and P. Saint-Andre, "PKIX over Secure HTTP
	(POSH)", draft-ietf-xmpp-posh-02 (work in progress),		(POSH)", draft-ietf-xmpp-posh-04 (work in progress),
	October 2014.		February 2015.
	[RFC3920] Saint-Andre, P., Ed., "Extensible Messaging and Presence		[RFC3920] Saint-Andre, P., Ed., "Extensible Messaging and Presence
	Protocol (XMPP): Core", RFC 3920, October 2004.		Protocol (XMPP): Core", RFC 3920, October 2004.
	[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S.		[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S.
	Rose, "DNS Security Introduction and Requirements", RFC		Rose, "DNS Security Introduction and Requirements", RFC
	4033, March 2005.		4033, March 2005.
	[RFC4422] Melnikov, A. and K. Zeilenga, "Simple Authentication and		[RFC4422] Melnikov, A. and K. Zeilenga, "Simple Authentication and
	Security Layer (SASL)", RFC 4422, June 2006.		Security Layer (SASL)", RFC 4422, June 2006.
	[RFC5386] Williams, N. and M. Richardson, "Better-Than-Nothing		[RFC5386] Williams, N. and M. Richardson, "Better-Than-Nothing
	Security: An Unauthenticated Mode of IPsec", RFC 5386,		Security: An Unauthenticated Mode of IPsec", RFC 5386,
	November 2008.		November 2008.
	[RFC6066] Eastlake, D., "Transport Layer Security (TLS) Extensions:		[RFC6066] Eastlake, D., "Transport Layer Security (TLS) Extensions:
	Extension Definitions", RFC 6066, January 2011.		Extension Definitions", RFC 6066, January 2011.
			[RFC7247] Saint-Andre, P., Houri, A., and J. Hildebrand,
			"Interworking between the Session Initiation Protocol
			(SIP) and the Extensible Messaging and Presence Protocol
			(XMPP): Architecture, Addresses, and Error Handling", RFC
			7247, May 2014.
			[RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an
			Attack", BCP 188, RFC 7258, May 2014.
			[RFC7457] Sheffer, Y., Holz, R., and P. Saint-Andre, "Summarizing
			Known Attacks on Transport Layer Security (TLS) and
			Datagram TLS (DTLS)", RFC 7457, February 2015.
	[XEP-0138]		[XEP-0138]
	Hildebrand, J. and P. Saint-Andre, "Stream Compression",		Hildebrand, J. and P. Saint-Andre, "Stream Compression",
	XSF XEP 0138, May 2009.		XSF XEP 0138, May 2009.
	[XEP-0170]		[XEP-0170]
	Saint-Andre, P., "Recommended Order of Stream Feature		Saint-Andre, P., "Recommended Order of Stream Feature
	Negotiation", XSF XEP 0170, January 2007.		Negotiation", XSF XEP 0170, January 2007.
	[XEP-0198]		[XEP-0198]
	Karneges, J., Saint-Andre, P., Hildebrand, J., Forno, F.,		Karneges, J., Saint-Andre, P., Hildebrand, J., Forno, F.,
	skipping to change at page 7, line 41 ¶		skipping to change at page 8, line 34 ¶
	Some governments enforce legislation prohibiting the export of strong		Some governments enforce legislation prohibiting the export of strong
	cryptographic technologies. Nothing in this document ought to be		cryptographic technologies. Nothing in this document ought to be
	taken as advice to violate such prohibitions.		taken as advice to violate such prohibitions.
	Appendix B. Acknowledgements		Appendix B. Acknowledgements
	The authors would like to thank the following individuals for their		The authors would like to thank the following individuals for their
	input: Dave Cridland, Philipp Hancke, Olle Johansson, Steve Kille,		input: Dave Cridland, Philipp Hancke, Olle Johansson, Steve Kille,
	Tobias Markmann, Matt Miller, and Rene Treffer.		Tobias Markmann, Matt Miller, and Rene Treffer.
			Roni Even caught several important issues in his review on behalf of
			the General Area Review Team.
			Thanks to Leif Johansson and Orit Levin as chairs of the UTA WG, Ben
			Campbell and Joe Hildebrand as chairs of the XMPP WG, and Stephen
			Farrell as the sponsoring Area Director.
	Authors' Addresses		Authors' Addresses
	Peter Saint-Andre		Peter Saint-Andre
	&yet		&yet
	Email: peter@andyet.com		Email: peter@andyet.com
	URI: https://andyet.com/		URI: https://andyet.com/
	Thijs Alkemade		Thijs Alkemade
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