draft-ietf-xmpp-e2e-08.txt   draft-ietf-xmpp-e2e-09.txt 
XMPP Working Group P. Saint-Andre XMPP Working Group P. Saint-Andre
Internet-Draft Jabber Software Foundation Internet-Draft Jabber Software Foundation
Expires: November 25, 2004 May 27, 2004 Expires: January 10, 2005 July 12, 2004
End-to-End Object Encryption in the Extensible Messaging and Presence End-to-End Signing and Object Encryption in the Extensible Messaging
Protocol (XMPP) and Presence Protocol (XMPP)
draft-ietf-xmpp-e2e-08 draft-ietf-xmpp-e2e-09
Status of this Memo Status of this Memo
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Abstract Abstract
This memo defines a method for end-to-end object signing and This memo defines a method for end-to-end signing and object
encryption in the Extensible Messaging and Presence Protocol (XMPP). encryption in the Extensible Messaging and Presence Protocol (XMPP).
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Securing Messages . . . . . . . . . . . . . . . . . . . . . . 4 3. Securing Messages . . . . . . . . . . . . . . . . . . . . . 5
4. Securing Presence . . . . . . . . . . . . . . . . . . . . . . 6 4. Securing Presence . . . . . . . . . . . . . . . . . . . . . 9
5. Securing Arbitrary XMPP Data . . . . . . . . . . . . . . . . . 8 5. Securing Arbitrary XMPP Data . . . . . . . . . . . . . . . . 13
6. Rules for S/MIME Generation and Handling . . . . . . . . . . . 10 6. Rules for S/MIME Generation and Handling . . . . . . . . . . 15
7. Secure Communications Through a Gateway . . . . . . . . . . . 13 7. Recipient Error Handling . . . . . . . . . . . . . . . . . . 18
8. urn:ietf:params:xml:xmpp-e2e Namespace . . . . . . . . . . . . 13 8. Secure Communications Through a Gateway . . . . . . . . . . 20
9. application/xmpp+xml Media Type . . . . . . . . . . . . . . . 14 9. urn:ietf:params:xml:xmpp-e2e Namespace . . . . . . . . . . . 20
10. Security Considerations . . . . . . . . . . . . . . . . . . . 14 10. application/xmpp+xml Media Type . . . . . . . . . . . . . . 21
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 11. Security Considerations . . . . . . . . . . . . . . . . . . 21
Normative References . . . . . . . . . . . . . . . . . . . . . 15 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . 21
Informative References . . . . . . . . . . . . . . . . . . . . 17 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 22
Author's Address . . . . . . . . . . . . . . . . . . . . . . . 17 13.1 Normative References . . . . . . . . . . . . . . . . . . . 22
A. Schema for urn:ietf:params:xml:ns:xmpp-e2e . . . . . . . . . . 18 13.2 Informative References . . . . . . . . . . . . . . . . . . 24
B. Revision History . . . . . . . . . . . . . . . . . . . . . . . 18 Author's Address . . . . . . . . . . . . . . . . . . . . . . 25
Intellectual Property and Copyright Statements . . . . . . . . 20 A. Schema for urn:ietf:params:xml:ns:xmpp-e2e . . . . . . . . . 25
B. Revision History . . . . . . . . . . . . . . . . . . . . . . 25
Intellectual Property and Copyright Statements . . . . . . . 28
1. Introduction 1. Introduction
This memo define a method for end-to-end signing and encryption in This memo define a method for end-to-end signing and object
the Extensible Messaging and Presence Protocol (XMPP). (For encryption in the Extensible Messaging and Presence Protocol (XMPP).
information about XMPP, see [XMPP-CORE] and [XMPP-IM].) The method (For information about XMPP, see [XMPP-CORE] and [XMPP-IM].) The
specified herein enables a sender to encrypt and/or sign an instant method specified herein enables a sender to sign and/or encrypt an
message sent to a specific recipient, encrypt and/or sign presence instant message sent to a specific recipient, sign and/or encrypt
information that is directed to a specific user, and sign presence presence information that is directed to a specific user, and sign
information that is broadcasted to a specific user. This memo and/or encrypt any arbitrary XMPP stanza directed to a specific user.
thereby helps the XMPP specifications meet the requirements specified This memo thereby helps the XMPP specifications meet the requirements
in [IMP-REQS]. specified in [IMP-REQS].
1.1 Terminology 1.1 Terminology
This document inherits terminology defined in [SMIME], [IMP-MODEL], This document inherits terminology defined in [CMS], [IMP-MODEL],
[CMS], and [XMPP-CORE]. [SMIME], and [XMPP-CORE].
The capitalized key words "MUST", "MUST NOT", "REQUIRED", "SHALL", The capitalized key words "MUST", "MUST NOT", "REQUIRED", "SHALL",
"SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "SHALL NOT", "SHOULD", "SHOULD 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
[TERMS]. [TERMS].
1.2 Discussion Venue
The authors welcome discussion and comments related to the topics
presented in this document. The preferred forum is the
<xmppwg@jabber.org> mailing list, for which archives and subscription
information are available at <<http://www.jabber.org/cgi-bin/mailman/
listinfo/xmppwg/>>.
2. Requirements 2. Requirements
For the purposes of this memo, we stipulate the following For the purposes of this memo, we stipulate the following
requirements: requirements:
1. The method defined MUST address encryption and signing 1. The method defined MUST address signing and encryption
requirements for minimal instant messaging and presence only, as requirements for minimal instant messaging and presence, as those
those are defined in [IMP-REQS]. The method is NOT REQUIRED to are defined in [IMP-REQS]. In particular, the method MUST
support non-IM applications of XMPP, nor to support advanced address the following requirements, which are copied here
instant messaging and presence functionality that is outside the verbatim from [IMP-REQS]:
scope of [IMP-REQS]. In particular, the method MUST address the
following requirements defined in [IMP-REQS]:
* The protocol MUST provide means to ensure confidence that a * The protocol MUST provide means to ensure confidence that a
received message (NOTIFICATION or INSTANT MESSAGE) has not received message (NOTIFICATION or INSTANT MESSAGE) has not
been corrupted or tampered with. (Section 2.5.1) been corrupted or tampered with. (Section 2.5.1)
* The protocol MUST provide means to ensure confidence that a * The protocol MUST provide means to ensure confidence that a
received message (NOTIFICATION or INSTANT MESSAGE) has not received message (NOTIFICATION or INSTANT MESSAGE) has not
been recorded and played back by an adversary. (Section been recorded and played back by an adversary. (Section
2.5.2) 2.5.2)
* The protocol MUST provide means to ensure that a sent message * The protocol MUST provide means to ensure that a sent message
(NOTIFICATION or INSTANT MESSAGE) is only readable by ENTITIES (NOTIFICATION or INSTANT MESSAGE) is only readable by ENTITIES
that the sender allows. (Section 2.5.3) that the sender allows. (Section 2.5.3)
skipping to change at page 4, line 26 skipping to change at page 4, line 16
* The protocol MUST provide A means of verifying that the * The protocol MUST provide A means of verifying that the
presence information is accurate, as sent by B. (Section presence information is accurate, as sent by B. (Section
5.3.1) 5.3.1)
* The protocol MUST provide A means of ensuring that no other * The protocol MUST provide A means of ensuring that no other
PRINCIPAL C can see the content of M. (Section 5.4.6) PRINCIPAL C can see the content of M. (Section 5.4.6)
* The protocol MUST provide A means of ensuring that no other * The protocol MUST provide A means of ensuring that no other
PRINCIPAL C can tamper with M, and B means to verify that no PRINCIPAL C can tamper with M, and B means to verify that no
tampering has occurred. (Section 5.4.7) tampering has occurred. (Section 5.4.7)
2. The method defined MUST enable interoperability with non-XMPP 2. The method defined MUST enable interoperability with non-XMPP
messaging systems that support the Common Presence and Instant messaging systems that support the Common Presence and Instant
Messaging (CPIM) specifications defined by the Instant Messaging Messaging (CPIM) specifications published by the Instant
and Presence (IMPP) Working Group. Therefore: Messaging and Presence (IMPP) Working Group. Two corollaries of
* Prior to encrypting or signing, the format of an instant this requirement are:
* Prior to signing and/or encrypting, the format of an instant
message MUST conform to the CPIM Message Format defined in message MUST conform to the CPIM Message Format defined in
[MSGFMT]. [MSGFMT].
* Prior to encrypting or signing, the format of presence * Prior to signing and/or encrypting, the format of presence
information MUST conform to the CPP Presence Information Data information MUST conform to the CPP Presence Information Data
Format defined in [PIDF]. Format defined in [PIDF].
3. The method MUST follow the required procedures (including the 3. The method MUST follow the required procedures (including the
specific algorithms) defined in [CPIM] and [CPP]. In particular, specific algorithms) defined in [CPIM] and [CPP]. In particular,
these documents specify: these documents specify:
* Signing MUST use [SMIME] signatures with [CMS] SignedData.
* Encryption MUST use [SMIME] encryption with [CMS] * Encryption MUST use [SMIME] encryption with [CMS]
EnvelopeData. EnvelopeData.
* Signing MUST use [SMIME] signatures with [CMS] SignedData.
4. In order to enable interoperable implementations, sending and 4. In order to enable interoperable implementations, sending and
receiving applications MUST implement the algorithms defined receiving applications MUST implement the algorithms specified
under Section 6.9. under Mandatory-to-Implement Cryptographic Algorithms (Section
6.10).
We further stipulate that the following functionality is out of scope
for this memo:
o Discovery of support for this protocol. An entity could discover
whether another entity supports this protocol by (1) attempting to
send signed or encrypted stanzas and receiving an error stanza
("technical" discovery) or a textual message in reply ("social"
discovery) if the protocol is not supported, or (2) using a
dedicated service discovery protocol, such as [DISCO] or [CAPS].
However, the definition of a service discovery protocol is out of
scope for this memo.
o Signing or encryption of XMPP groupchat messages, which are
mentioned in [XMPP-IM] but not defined therein since they are not
required by [IMP-REQS]; such messages are best specified in [MUC].
o Signing or encryption of broadcasted presence as described in
[XMPP-IM] (the methods defined herein apply to directed presence
only).
o Signing or encryption of communications that occur within the
context of applications other than instant messaging and presence
as those are described in [IMP-MODEL] and [IMP-REQS].
3. Securing Messages 3. Securing Messages
In order to encrypt a message, a sending entity MUST use the 3.1 Process for Securing Messages
following procedure:
In order to sign and/or encrypt a message, a sending agent MUST use
the following procedure:
1. Generate a "Message/CPIM" object as defined in [MSGFMT]. 1. Generate a "Message/CPIM" object as defined in [MSGFMT].
2. Encrypt and/or sign both the headers and content of the "Message/ 2. Sign and/or encrypt both the headers and content of the "Message/
CPIM" object as specified in Requirement 3 of Section 2 above. CPIM" object as specified in Requirement 3 of Section 2 above.
3. Provide the resulting signed and/or encrypted object within an
XML CDATA section (see Section 2.7 of [XML]) contained in an
<e2e/> child of a <message/> stanza, where the <e2e/> element is
qualified by the 'urn:ietf:params:xml:ns:xmpp-e2e' namespace as
specified more fully in Section 9 below.
3. Provide the resulting multipart [SMIME] object (see [MULTI]) 3.2 Example of a Signed Message
within a CDATA section of an <e2e/> child of a <message/> stanza,
where the <e2e/> element is qualified by the The following example illustrates the defined steps for signing a
'urn:ietf:params:xml:ns:xmpp-e2e' namespace as specified more message.
fully in Section 8 below.
First, the sending agent generates a "Message/CPIM" object in
accordance with the rules and formats specified in [MSGFMT].
Example 1: Sender generates "Message/CPIM" object: Example 1: Sender generates "Message/CPIM" object:
Content-type: Message/CPIM | Content-type: Message/CPIM
|
| From: Juliet Capulet <im:juliet@example.com>
| To: Romeo Montague <im:romeo@example.net>
| DateTime: 2003-12-09T11:45:36.66Z
| Subject: Imploring
|
| Content-type: text/plain; charset=utf-8
| Content-ID: <1234567890@example.com>
|
| Wherefore art thou, Romeo?
From: Juliet Capulet <im:juliet@example.com> Once the sending agent has generated the "Message/CPIM" object, the
To: Romeo Montague <im:romeo@example.net> sending agent may sign it. The result is a multipart [SMIME] object
DateTime: 2003-12-09T11:45:36.66Z (see [MULTI]) that has a Content-Type of "multipart/signed" and
Subject: Imploring includes two parts: one whose Content-Type is "Message/CPIM" and
another whose Content-Type is "application/pkcs7-signature".
Content-type: text/plain; charset=utf-8 Example 2: Sender generates multipart/signed object:
Content-ID: <1234567890@example.com>
Wherefore art thou, Romeo? | Content-Type: multipart/signed; boundary=next;
Example 2: Sender generates signed message (the 'from' address on the | micalg=sha1;
XMPP message stanza is stamped by sender's server): | protocol=application/pkcs7-signature
|
| --next
| Content-type: Message/CPIM
|
| From: Juliet Capulet <im:juliet@example.com>
| To: Romeo Montague <im:romeo@example.net>
| DateTime: 2003-12-09T23:45:36.66Z
| Subject: Imploring
|
| Content-type: text/plain; charset=utf-8
| Content-ID: <1234567890@example.com>
|
| Wherefore art thou, Romeo?
| --next
| Content-Type: application/pkcs7-signature
| Content-Disposition: attachment;handling=required;\
| filename=smime.p7s
|
| [signed body part]
|
| --next--
<message to='romeo@example.net/orchard' type='chat'> The sending agent now wraps the "mulipart/signed" object in an XML
<e2e xmlns='urn:ietf:params:xml:ns:xmpp-e2e'> CDATA section, which is contained in an <e2e/> element that is
<![CDATA[ included as a child element of the XMPP message stanza and that is
Content-Type: multipart/signed; boundary=next; qualified by the 'urn:ietf:params:xml:ns:xmpp-e2e' namespace.
micalg=sha1;
protocol=application/pkcs7-signature
--next Example 3: Sender generates XMPP message stanza:
Content-type: Message/CPIM
From: Juliet Capulet <im:juliet@example.com> | <message to='romeo@example.net/orchard' type='chat'>
To: Romeo Montague <im:romeo@example.net> | <e2e xmlns='urn:ietf:params:xml:ns:xmpp-e2e'>
DateTime: 2003-12-09T23:45:36.66Z | <![CDATA[
Subject: Imploring | Content-Type: multipart/signed; boundary=next;
| micalg=sha1;
| protocol=application/pkcs7-signature
|
| --next
| Content-type: Message/CPIM
|
| From: Juliet Capulet <im:juliet@example.com>
| To: Romeo Montague <im:romeo@example.net>
| DateTime: 2003-12-09T23:45:36.66Z
| Subject: Imploring
|
| Content-type: text/plain; charset=utf-8
| Content-ID: <1234567890@example.com>
|
| Wherefore art thou, Romeo?
| --next
| Content-Type: application/pkcs7-signature
| Content-Disposition: attachment;handling=required;\
| filename=smime.p7s
|
| [signed body part]
|
| --next--
| ]]>
| </e2e>
| </message>
Content-type: text/plain; charset=utf-8 3.3 Example of an Encrypted Message
Content-ID: <1234567890@example.com>
Wherefore art thou, Romeo? The following example illustrates the defined steps for encrypting a
--next message.
Content-Type: application/pkcs7-signature
Content-Disposition: attachment;handling=required;filename=smime.p7s
[signed body part] First, the sending agent generates a "Message/CPIM" object in
accordance with the rules and formats specified in [MSGFMT].
--next-- Example 4: Sender generates "Message/CPIM" object:
]]>
</e2e> | Content-type: Message/CPIM
</message> |
| From: Juliet Capulet <im:juliet@example.com>
| To: Romeo Montague <im:romeo@example.net>
| DateTime: 2003-12-09T11:45:36.66Z
| Subject: Imploring
|
| Content-type: text/plain; charset=utf-8
| Content-ID: <1234567890@example.com>
|
| Wherefore art thou, Romeo?
Once the sending agent has generated the "Message/CPIM" object, the
sending agent may encrypt it.
Example 5: Sender generates encrypted object:
| U2FsdGVkX19okeKTlLxa/1n1FE/upwn1D20GhPWqhDWlexKMUKYJInTWzERP+vcQ
| /OxFs40uc9Fx81a5/62p/yPb/UWnuG6SR6o3Ed2zwcusDImyyz125HFERdDUMBC9
| Pt6Z4cTGKBmJzZBGyuc3Y+TMBTxqFFUAxeWaoxnZrrl+LP72vwbriYc3KCMxDbQL
| Igc1Vzs5/5JecegMieNY24SlNyX9HMFRNFpbI64vLxYEk55A+3IYbZsluCFT31+a
| +GeAvJkvH64LRV4mPbUhENTQ2wbAwnOTvbLIaQEQrii78xNEh+MK8Bx7TBTvi4yH
| Ddzf9Sim6mtWsXaCAvWSyp0X91d7xRJ4JIgKfPzkxNsWJFCLthQS1p734eDxXVd3
| i08lEHzyll6htuEr59ZDAw==
The sending agent now wraps the encrypted object in an XML CDATA
section, which is contained in an <e2e/> element that is included as
a child element of the XMPP message stanza and that is qualified by
the 'urn:ietf:params:xml:ns:xmpp-e2e' namespace.
Example 6: Sender generates XMPP message stanza:
| <message to='romeo@example.net/orchard' type='chat'>
| <e2e xmlns='urn:ietf:params:xml:ns:xmpp-e2e'>
| <![CDATA[
| U2FsdGVkX19okeKTlLxa/1n1FE/upwn1D20GhPWqhDWlexKMUKYJInTWzERP+vcQ
| /OxFs40uc9Fx81a5/62p/yPb/UWnuG6SR6o3Ed2zwcusDImyyz125HFERdDUMBC9
| Pt6Z4cTGKBmJzZBGyuc3Y+TMBTxqFFUAxeWaoxnZrrl+LP72vwbriYc3KCMxDbQL
| Igc1Vzs5/5JecegMieNY24SlNyX9HMFRNFpbI64vLxYEk55A+3IYbZsluCFT31+a
| +GeAvJkvH64LRV4mPbUhENTQ2wbAwnOTvbLIaQEQrii78xNEh+MK8Bx7TBTvi4yH
| Ddzf9Sim6mtWsXaCAvWSyp0X91d7xRJ4JIgKfPzkxNsWJFCLthQS1p734eDxXVd3
| i08lEHzyll6htuEr59ZDAw==
| ]]>
| </e2e>
| </message>
4. Securing Presence 4. Securing Presence
In order to encrypt presence information, a sending entity MUST use 4.1 Process for Securing Presence Information
the following procedure:
In order to sign and/or encrypt presence information, a sending agent
MUST use the following procedure:
1. Generate an "application/pidf+xml" object as defined in [PIDF]. 1. Generate an "application/pidf+xml" object as defined in [PIDF].
2. Encrypt and/or sign the "application/pidf+xml" object as 2. Sign and/or encrypt the "application/pidf+xml" object as
specified in Requirement 3 of Section 2 above. specified in Requirement 3 of Section 2 above.
3. Provide the resulting [SMIME] object within a CDATA section of an 3. Provide the resulting signed and/or encrypted object within an
XML CDATA section (see Section 2.7 of [XML]) contained in an
<e2e/> child of a <presence/> stanza, where the <e2e/> element is <e2e/> child of a <presence/> stanza, where the <e2e/> element is
qualified by the 'urn:ietf:params:xml:ns:xmpp-e2e' namespace. qualified by the 'urn:ietf:params:xml:ns:xmpp-e2e' namespace.
The <presence/> stanza MUST include a 'to' attribute, i.e., it The <presence/> stanza MUST include a 'to' attribute, i.e., it
must be an instance of directed presence as defined in [XMPP-IM]. must be an instance of directed presence as defined in [XMPP-IM].
Example 3: Sender generates "application/pidf+xml" object: 4.2 Example of Signed Presence Information
<?xml version="1.0" encoding="UTF-8"?> The following example illustrates the defined steps for signing
<presence xmlns="urn:ietf:params:xml:ns:pidf" presence information.
xmlns:im="urn:ietf:params:xml:ns:pidf:im"
entity="pres:juliet@example.com">
<tuple id="h40zny"
<status>
<basic>open</basic>
<im:im>away</im:im>
</status>
<note xml:lang="en">retired to the chamber</note>
<timestamp>2003-12-09T23:53:11.31</timestamp>
</tuple>
</presence>
Example 4: Sender generates signed presence (the 'from' address on
the XMPP presence stanza is stamped by sender's server):
<presence to='romeo@example.net/orchard'> First, the sending agent generates an "application/pidf+xml" object
<e2e xmlns='urn:ietf:params:xml:ns:xmpp-e2e'> in accordance with the rules and formats specified in [PIDF].
<![CDATA[
Content-Type: multipart/signed; boundary=next;
micalg=sha1;
protocol=application/pkcs7-signature
--next Example 7: Sender generates "application/pidf+xml" object:
Content-type: application/pidf+xml
Content-ID: <2345678901@example.com>
<xml version="1.0" encoding="UTF-8"?> | <?xml version="1.0" encoding="UTF-8"?>
<presence xmlns="urn:ietf:params:xml:ns:pidf" | <presence xmlns="urn:ietf:params:xml:ns:pidf"
xmlns:im="urn:ietf:params:xml:ns:pidf:im" | xmlns:im="urn:ietf:params:xml:ns:pidf:im"
entity="pres:juliet@example.com"> | entity="pres:juliet@example.com">
<tuple id="hr0zny"> | <tuple id="hr0zny"
<status> | <status>
<basic>open</basic> | <basic>open</basic>
<im:im>away</im:im> | <im:im>away</im:im>
</status> | </status>
<note xml:lang="en">retired to the chamber</note> | <note xml:lang="en">retired to the chamber</note>
<timestamp>2003-12-09T23:53:11.31Z</timestamp> | <timestamp>2003-12-09T23:53:11.31</timestamp>
</tuple> | </tuple>
</presence> | </presence>
--next
Content-Type: application/pkcs7-signature
Content-Disposition: attachment;handling=required;filename=smime.p7s
[signed body part] Once the sending agent has generated the "application/pidf+xml"
object, the sending agent may sign it. The result is a multipart
[SMIME] object (see [MULTI]) that has a Content-Type of "multipart/
signed" and includes two parts: one whose Content-Type is
"application/pidf+xml" and another whose Content-Type is
"application/pkcs7-signature".
--next-- Example 8: Sender generates multipart/signed object:
]]>
</e2e> | Content-Type: multipart/signed; boundary=next;
</presence> | micalg=sha1;
| protocol=application/pkcs7-signature
|
| --next
| Content-type: application/pidf+xml
| Content-ID: <2345678901@example.com>
|
| <xml version="1.0" encoding="UTF-8"?>
| <presence xmlns="urn:ietf:params:xml:ns:pidf"
| xmlns:im="urn:ietf:params:xml:ns:pidf:im"
| entity="pres:juliet@example.com">
| <tuple id="hr0zny">
| <status&gt;
| <basic>open</basic>
| <im:im>away</im:im>
| </status>
| <note xml:lang="en">retired to the chamber</note>
| <timestamp>2003-12-09T23:53:11.31Z</timestamp>
| </tuple>
| </presence>
| --next
| Content-Type: application/pkcs7-signature
| Content-Disposition: attachment;handling=required;\
| filename=smime.p7s
|
| [signed body part]
|
| --next--
The sending agent now wraps the "mulipart/signed" object in an XML
CDATA section, which is contained in an <e2e/> element that is
included as a child element of the XMPP message stanza and that is
qualified by the 'urn:ietf:params:xml:ns:xmpp-e2e' namespace.
Example 9: Sender generates XMPP presence stanza:
| <presence to='romeo@example.net/orchard'>
| <e2e xmlns='urn:ietf:params:xml:ns:xmpp-e2e'>
| <![CDATA[
| Content-Type: multipart/signed; boundary=next;
| micalg=sha1;
| protocol=application/pkcs7-signature
|
| --next
| Content-type: application/pidf+xml
| Content-ID: <2345678901@example.com>
|
| <xml version="1.0" encoding="UTF-8"?>
| <presence xmlns="urn:ietf:params:xml:ns:pidf"
| xmlns:im="urn:ietf:params:xml:ns:pidf:im"
| entity="pres:juliet@example.com">
| <tuple id="hr0zny">
| <status>
| <basic>open</basic>
| <im:im>away</im:im>
| </status>
| <note xml:lang="en">retired to the chamber</note>
| <timestamp>2003-12-09T23:53:11.31Z</timestamp>
| </tuple>
| </presence>
| --next
| Content-Type: application/pkcs7-signature
| Content-Disposition: attachment;handling=required;\
| filename=smime.p7s
|
| [signed body part]
|
| --next--
| ]]>
| </e2e>
| </presence>
4.3 Example of Encrypted Presence Information
The following example illustrates the defined steps for encrypting
presence information.
First, the sending agent generates an "application/pidf+xml" object
in accordance with the rules and formats specified in [PIDF].
Example 10: Sender generates "application/pidf+xml" object:
| <?xml version="1.0" encoding="UTF-8"?>
| <presence xmlns="urn:ietf:params:xml:ns:pidf"
| xmlns:im="urn:ietf:params:xml:ns:pidf:im"
| entity="pres:juliet@example.com">
| <tuple id="hr0zny"
| <status>
| <basic>open</basic>
| <im:im>away</im:im>
| </status>
| <note xml:lang="en">retired to the chamber</note>
| <timestamp>2003-12-09T23:53:11.31</timestamp>
| </tuple>
| </presence>
Once the sending agent has generated the "application/pidf+xml"
object, the sending agent may encrypt it.
Example 11: Sender generates encrypted object:
| U2FsdGVkX18VJPbx5GMdFPTPZrHLC9QGiVP+ziczu6zWZLFQxae6O5PP6iqpr2No
| zOvBVMWvYeRAT0zd18hr6qsqKiGl/GZpAAbTvPtaBxeIykxsd1+CX+U+iw0nEGCr
| bjiQrk0qUKJ79bNxwRnqdidjhyTpKSbOJC0XZ8CTe7AE9KDM3Q+uk+O3jrqX4byL
| GBlKThbzKidxz32ObojPEEwfFiM/yUeqYUP1OcJpUmeQ8lcXhD6tcx+m2MAyYYLP
| boKQxpLknxRnbM8T/voedlnFLbbDu69mOlxDPbr1mHZd3hDsyFudb1fb4rI3Kw0K
| Nq+3udr2IkysviJDgQo+xGIQUG/5sED/mAaPRlj4f/JtTzvT4EaQTawv69ntXfKV
| MCr9KdIMMdjdJzOJkYLoAhNVrcZn5tw8WsJGwuKuhYb/SShy7InzOapPaPAl7/Mm
| PHj7zj3NZ6EEIweDOuAwWlIG/dT506tci27+EW7JnXwMPnFMkF+6a7tr/0Y+iiej
| woJxUIBqCOgX+U7srHpK2NYtNTZ7UQp2V0yEx1JV8+Y=
The sending agent now wraps the encrypted object in an XML CDATA
section, which is contained in an <e2e/> element that is included as
a child element of the XMPP message stanza and that is qualified by
the 'urn:ietf:params:xml:ns:xmpp-e2e' namespace.
Example 12: Sender generates XMPP presence stanza:
| <presence to='romeo@example.net/orchard'>
| <e2e xmlns='urn:ietf:params:xml:ns:xmpp-e2e'>
| <![CDATA[
| U2FsdGVkX18VJPbx5GMdFPTPZrHLC9QGiVP+ziczu6zWZLFQxae6O5PP6iqpr2No
| zOvBVMWvYeRAT0zd18hr6qsqKiGl/GZpAAbTvPtaBxeIykxsd1+CX+U+iw0nEGCr
| bjiQrk0qUKJ79bNxwRnqdidjhyTpKSbOJC0XZ8CTe7AE9KDM3Q+uk+O3jrqX4byL
| GBlKThbzKidxz32ObojPEEwfFiM/yUeqYUP1OcJpUmeQ8lcXhD6tcx+m2MAyYYLP
| boKQxpLknxRnbM8T/voedlnFLbbDu69mOlxDPbr1mHZd3hDsyFudb1fb4rI3Kw0K
| Nq+3udr2IkysviJDgQo+xGIQUG/5sED/mAaPRlj4f/JtTzvT4EaQTawv69ntXfKV
| MCr9KdIMMdjdJzOJkYLoAhNVrcZn5tw8WsJGwuKuhYb/SShy7InzOapPaPAl7/Mm
| PHj7zj3NZ6EEIweDOuAwWlIG/dT506tci27+EW7JnXwMPnFMkF+6a7tr/0Y+iiej
| woJxUIBqCOgX+U7srHpK2NYtNTZ7UQp2V0yEx1JV8+Y=
| ]]>
| </e2e>
| </presence>
5. Securing Arbitrary XMPP Data 5. Securing Arbitrary XMPP Data
The foregoing sections of this memo describe how to secure "least The foregoing sections of this memo describe how to secure "least
common denominator" messaging and presence data of the kind that can common denominator" messaging and presence data of the kind that can
be directly translated into the MSGFMT or PIDF formats. However, be directly translated into the MSGFMT or PIDF formats. However,
XMPP possesses a third base-level stanza type (<iq/>) in addition to XMPP possesses a third base-level stanza type (<iq/>) in addition to
<message/> and <presence/>, as well as the ability to include <message/> and <presence/>, as well as the ability to include
extended XML data within arbitrary child elements of the three core extended XML data within arbitrary child elements of the three core
stanza types. Therefore it would be desirable to secure such data if stanza types. Therefore it would be desirable to secure such data if
possible. possible.
Because [MSGFMT] specifies the ability to encapsulate any MIME type, Because [MSGFMT] specifies the ability to encapsulate any MIME type,
the approach taken in this memo is to include arbitrary XMPP data in the approach taken in this memo is to include arbitrary XMPP data in
an XML media type named "application/xmpp+xml" as specified more an XML media type named "application/xmpp+xml" as specified more
fully in Section 9 below. fully in Section 10 below.
The following examples illustrate the structure of the "application/ The following examples illustrate the structure of the "application/
xmpp+xml" MIME type. xmpp+xml" MIME type. (Note: The 'http://jabber.org/protocol/evil'
namespace used in these examples is associated with an April Fool's
Example 5: Message stanza with extended data contained in protocol written to be the instant messaging equivalent of RFC 3514;
it is included only as an instance of extended information included
in an XML stanza and should not be taken seriously as a functional
XMPP extension.)
Example 13: Message stanza with extended data contained in
"application/xmpp+xml" MIME type: "application/xmpp+xml" MIME type:
<?xml version='1.0' encoding='UTF-8'?> | <?xml version='1.0' encoding='UTF-8'?>
<xmpp xmlns='jabber:client'> | <xmpp xmlns='jabber:client'>
<message | <message
from='iago@example.com/pda' | from='iago@example.com/pda'
to='emilia@example.com/cell'> | to='emilia@example.com/cell'>
<body> | <body>
I told him what I thought, and told no more | I told him what I thought, and told no more
Than what he found himself was apt and true. | Than what he found himself was apt and true.
</body> | </body>
<evil xmlns='http://jabber.org/protocol/evil'/> | <evil xmlns='http://jabber.org/protocol/evil'/>
</message> | </message>
</xmpp> | </xmpp>
Example 6: Presence stanza with extended data contained in Example 14: Presence stanza with extended data contained in
"application/xmpp+xml" MIME type: "application/xmpp+xml" MIME type:
<?xml version='1.0' encoding='UTF-8'?> | <?xml version='1.0' encoding='UTF-8'?>
<xmpp xmlns='jabber:client'> | <xmpp xmlns='jabber:client'>
<presence from='iago@example.com/pda'> | <presence from='iago@example.com/pda'>
<show>dnd</show> | <show>dnd</show>
<status>Fomenting dissension</status> | <status>Fomenting dissension</status>
<evil xmlns='http://jabber.org/protocol/evil'/> | <evil xmlns='http://jabber.org/protocol/evil'/>
</presence> | </presence>
</xmpp> | </xmpp>
Example 7: IQ stanza with extended data contained in "application/
Example 15: IQ stanza with extended data contained in "application/
xmpp+xml" MIME type: xmpp+xml" MIME type:
<?xml version='1.0' encoding='UTF-8'?> | <?xml version='1.0' encoding='UTF-8'?>
<xmpp xmlns='jabber:client'> | <xmpp xmlns='jabber:client'>
<iq type='result' | <iq type='result'
from='iago@example.com/pda' | from='iago@example.com/pda'
to='emilia@example.com/cell' | to='emilia@example.com/cell'
id='evil1'> | id='evil1'>
<query xmlns='jabber:iq:version'> | <query xmlns='jabber:iq:version'>
<name>Stabber</name> | <name>Stabber</name>
<version>666</version> | <version>666</version>
<os>FiendOS</os> | <os>FiendOS</os>
</query> | </query>
<evil xmlns='http://jabber.org/protocol/evil'/> | <evil xmlns='http://jabber.org/protocol/evil'/>
</iq> | </iq>
</xmpp> | </xmpp>
Just as with the "Message/CPIM" and "application/pidf+xml" objects,
the "application/xmpp+xml" object would be signed and/or encrypted,
then encapsulated within an XML CDATA section (see Section 2.7 of
[XML]) contained in an <e2e/> child of a <presence/> stanza, where
the <e2e/> element is qualified by the
'urn:ietf:params:xml:ns:xmpp-e2e' namespace.
6. Rules for S/MIME Generation and Handling 6. Rules for S/MIME Generation and Handling
6.1 Certificate Enrollment 6.1 Certificate Enrollment
[SMIME] does not specify how to obtain a certificate from a [SMIME] does not specify how to obtain a certificate from a
certificate authority, but instead mandates that every sending agent certificate authority, but instead mandates that every sending agent
must already have a certificate. The PKIX Working Group has, at the must already have a certificate. The PKIX Working Group has, at the
time of this writing, produced two separate standards for certificate time of this writing, produced two separate standards for certificate
enrollment: [CMP] and [CMC]. Which method to use for certificate enrollment: [CMP] and [CMC]. Which method to use for certificate
enrollment is outside the scope of this memo. enrollment is outside the scope of this memo.
6.2 Certificate Retrieval 6.2 Certificate Retrieval
A receiving agent MUST provide some certificate retrieval mechanism A receiving agent MUST provide some certificate retrieval mechanism
in order to gain access to certificates for recipients of digital in order to gain access to certificates for recipients of digital
envelopes. This memo does not cover how S/MIME agents handle envelopes. This memo does not address how S/MIME agents handle
certificates, only what they do after a certificate has been certificates, only what they do after a certificate has been
validated or rejected. S/MIME certification issues are covered in validated or rejected. S/MIME certification issues are covered in
[CERT]. [CERT].
At a minimum, for initial S/MIME deployment, a user agent could However, at a minimum, for initial S/MIME deployment, a user agent
automatically generate a message to an intended recipient requesting SHOULD automatically generate a message to an intended recipient
that recipient's certificate in a signed return message. Receiving requesting that recipient's certificate in a signed return message.
and sending agents SHOULD also provide a mechanism to allow a user to Receiving and sending agents SHOULD also provide a mechanism to allow
"store and protect" certificates for correspondents in such a way so a user to "store and protect" certificates for correspondents in such
as to guarantee their later retrieval. a way so as to guarantee their later retrieval.
6.3 Certificate Names 6.3 Certificate Names
End-entity certificates used by XMPP entities in the context of this End-entity certificates used by XMPP entities in the context of this
memo SHOULD contain a valid instant messaging and presence address. memo SHOULD contain a valid instant messaging and presence address.
The address SHOULD be specified as both an 'im:' URI (for instant The address SHOULD be specified as both an 'im:' URI (for instant
messaging, as defined in [CPIM]) and a 'pres:' URI (for presence, as messaging, as defined in [CPIM]) and a 'pres:' URI (for presence, as
defined in [CPP]); each of these URIs SHOULD be specified in a defined in [CPP]); each of these URIs SHOULD be specified in a
separate GeneralName entry of type uniformResourceIdentifier inside separate GeneralName entry of type uniformResourceIdentifier inside
the subjectAltName (i.e., two separate entries). Information in the the subjectAltName (i.e., two separate entries). Information in the
subject distinguished name SHOULD be ignored. subject distinguished name SHOULD be ignored.
Each URI MUST be of the form <im:address> or <pres:address>, where Each URI MUST be of the form <im:address> or <pres:address>, where
the "address" portion is an XMPP address (also referred to as a the "address" portion is an XMPP address (also referred to as a
Jabber Identifier or JID) as defined in [XMPP-CORE], prepended with Jabber Identifier or JID) as defined in [XMPP-CORE], prepended with
the 'im:' or 'pres:' URI scheme. The address SHOULD be of the form the 'im:' or 'pres:' URI scheme. The address SHOULD be of the form
<node@domain> (i.e., a "bare JID"), although any valid JID form MAY <node@domain> (i.e., a "bare JID"), although any valid JID form MAY
be used. be used.
The value of the JID contained in the XMPP 'from' attribute SHOULD The value of the JID contained in the XMPP 'from' attribute MUST
match the JID provided in the signer's certificate, with the match a JID provided in the signer's certificate, with the exception
exception that the resource identifier portion of the JID contained that the resource identifier portion of the JID contained in the
in the 'from' attribute SHOULD be ignored for matching purposes. 'from' attribute SHOULD be ignored for matching purposes.
Receiving agents SHOULD check that sending JID matches a JID provided Receiving agents MUST check that the sending JID matches a JID
in the signer's certificate, with the exception that the resource provided in the signer's certificate, with the exception that the
identifier portion of the JID contained in the 'from' attribute MAY resource identifier portion of the JID contained in the 'from'
be ignored for matching purposes. A receiving agent SHOULD provide attribute SHOULD be ignored for matching purposes. A receiving agent
some explicit alternate processing of the message if this comparison SHOULD provide some explicit alternate processing of the stanza if
fails, which may be to display a message that shows the recipient the this comparison fails, which may be to display a message informing
addresses in the certificate or other certificate details. the recipient of the addresses in the certificate or other
certificate details.
The subject alternative name extension is used in S/MIME as the The subject alternative name extension is used in S/MIME as the
preferred means to convey the instant messaging and presence address preferred means to convey the instant messaging and presence address
that corresponds to the entity for this certificate. Any instant that corresponds to the entity for this certificate. Any XMPP
messaging or presence address present in the certificate SHOULD be address present in the certificate MUST be encoded using the ASN.1
encoded using the otherName choice of the subjectAltName type along Object Identifier "id-on-xmppAddr" as specified in Section 5.1.1 of
with a type-id of "xmpp" (as these terms are profiled in [X509]). [XMPP-CORE].
6.4 Transfer Encoding 6.4 Transfer Encoding
Because it is expected that XMPP applications will not interface with Because it is expected that XMPP applications will not interface with
older 7-bit systems, the transfer encoding (as defined in Section older 7-bit systems, the transfer encoding (as defined in Section
3.1.2 of [SMIME]) MUST be "binary". 3.1.2 of [SMIME]) MUST be "binary".
6.5 Attachment of Signatures 6.5 Order of Signing and Encrypting
Sending agents SHOULD attach a signature to each encrypted message or If a stanza is both signed and encrypted, it SHOULD be signed first,
presence stanza. If a signature is attached, a Content-Disposition then encrypted.
header field (as defined in [DISP]) SHOULD be included to specify how
the signature is to be handled by the receiving application.
6.6 Inclusion of Certificates 6.6 Inclusion of Certificates
If the sender and recipient are involved in an active messaging If the sender and recipient are involved in an active messaging
session over a period of time, the sending agent SHOULD include the session over a period of time, the sending agent SHOULD include the
sender's certificate along with at least one encrypted message stanza sender's certificate along with at least one encrypted message stanza
every five minutes. Outside the context of an active messaging every five minutes. Outside the context of an active messaging
session, the sending agent SHOULD include the sender's certificate session, the sending agent SHOULD include the sender's certificate
along with each encrypted message stanza. A sending agent MAY along with each encrypted message stanza. A sending agent MAY
include the sender's certificate along with each encrypted presence include the sender's certificate along with each encrypted presence
stanza. However, a sending agent SHOULD NOT include a certificate stanza. However, a sending agent SHOULD NOT include a certificate
more than once every five minutes. more than once every five minutes.
6.7 Order of Signing and Encrypting 6.7 Attachment and Checking of Signatures
If a stanza is both signed and encrypted, it SHOULD be signed first, Sending agents SHOULD attach a signature to each encrypted XML
then encrypted. stanza. If a signature is attached, a Content-Disposition header
field (as defined in [DISP]) SHOULD be included to specify how the
signature is to be handled by the receiving application.
6.8 Checking of Timestamps If the receiving agent determines that the signature attached to an
encrypted XML stanza is invalid, it SHOULD NOT present the stanza to
the intended recipient (human or application), SHOULD provide some
explicit alternate processing of the stanza (which may be to display
a message informing the recipient that the attached signature is
invalid), and MAY return a stanza error to the sender as described
under Recipient Error Handling (Section 7).
6.8 Decryption
If the receiving agent is unable to decrypt the encrypted XML stanza,
it SHOULD NOT present the stanza to the intended recipient (human or
application), SHOULD provide some explicit alternate processing of
the stanza (which may be to display a message informing the recipient
that it has received a stanza that cannot be decrypted), and MAY
return a stanza error to the sender as described under Recipient
Error Handling (Section 7).
6.9 Inclusion and Checking of Timestamps
Timestamps are included in "Message/CPIM" and "application/pidf+xml" Timestamps are included in "Message/CPIM" and "application/pidf+xml"
objects to help prevent replay attacks. All timestamps MUST conform objects to help prevent replay attacks. All timestamps MUST conform
to [DATETIME] and be presented as UTC with no offset, including to [DATETIME] and be presented as UTC with no offset, including
fractions of a second as appropriate. Absent a local adjustment to fractions of a second as appropriate. Absent a local adjustment to
the sending application's perceived time or the underlying clock the sending agent's perceived time or the underlying clock time, the
time, the sending application MUST ensure that the timestamps it sending agent MUST ensure that the timestamps it sends to the
sends to the receiver increase monotonically (if necessary by receiver increase monotonically (if necessary by incrementing the
incrementing the seconds fraction in the timestamp if the clock seconds fraction in the timestamp if the clock returns the same time
returns the same time for multiple requests). The following rules for multiple requests). The following rules apply to the receiving
apply to the receiving application: application:
o it MUST verify that the timestamp received is within five minutes o It MUST verify that the timestamp received is within five minutes
of the current time of the current time.
o it SHOULD verify that the timestamp received is greater than any o It SHOULD verify that the timestamp received is greater than any
timestamp received in the last 10 minutes which passed the timestamp received in the last 10 minutes which passed the
previous check previous check.
o if any of the foregoing checks fails, the timestamp SHOULD be o If any of the foregoing checks fails, the timestamp SHOULD be
presented to the receiving entity (human or via an API) marked as presented to the receiving entity (human or application) marked as
"old timestamp", "future timestamp", or "decreasing timestamp" "old timestamp", "future timestamp", or "decreasing timestamp",
and the receiving entity MAY return a stanza error to the sender
as described under Recipient Error Handling (Section 7).
6.9 Mandatory to Implement Technologies 6.10 Mandatory-to-Implement Cryptographic Algorithms
At a minimum, all implementations MUST support the following CMS All implementations MUST support the following algorithms.
algorithms as defined in [CMS-ALG]: Implementations MAY support other algorithms as well.
for digest: SHA-1 For CMS SignedData:
for signing: RSA
for content encryption: AES
7. Secure Communications Through a Gateway o The SHA-1 message digest as specified in [CMS-ALG] section 2.1.
o The RSA (PKCS #1 v1.5) with SHA-1 signature algorithm, as
specified in [CMS-ALG] section 3.2.
For CMS EnvelopedData:
o The RSA (PKCS #1 v1.5) key transport, as specified in [CMS-ALG]
section 4.2.1.
o The AES-128 encryption algorithm in CBC mode, as specified in
[CMS-AES].
7. Recipient Error Handling
When an XMPP entity receives an XML stanza containing data that is
signed and/or encrypted using the protocol described herein, several
scenarios are possible:
Case #1: The receiving application does not understand the protocol.
Case #2: The receiving application understands the protocol and is
able to decrypt the payload and verify the sender's signature.
Case #3: The receiving application understands the protocol and is
able to decrypt the payload and verify the sender's signature, but
the timestamps fail the checks specified above under Checking of
Timestamps (Section 6.9).
Case #4: The receiving application understands the protocol and is
able to decrypt the payload but is unable to verify the sender's
signature.
Case #5: The receiving application understands the protocol but is
unable to decrypt the payload.
In Case #1, the receiving application MUST do one and only one of the
following: (1) ignore the <e2e/> extension, (2) ignore the entire
stanza, or (3) return a <service-unavailable/> error to the sender,
as described in [XMPP-CORE].
In Case #2, the receiving application MUST NOT return a stanza error
to the sender, since this is the success case.
In Case #3, the receiving application MAY return a <not-acceptable/>
error to the sender (as described in [XMPP-CORE]), optionally
supplemented by an application-specific error condition element
<bad-timestamp/> as shown below:
Example 16: Recipient returns <not-acceptable/> error:
<message from='romeo@example.net/orchard' type='chat'>
<e2e xmlns='urn:ietf:params:xml:ns:xmpp-e2e'>
[CDATA section here]
</e2e>
<error type='modify'>
<not-acceptable xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'/>
<bad-timestamp xmlns='urn:ietf:params:xml:xmpp-e2e'/>
</error>
</message>
In Case #4, the receiving application SHOULD return a
<not-acceptable/> error to the sender (as described in [XMPP-CORE]),
optionally supplemented by an application-specific error condition
element <unverified-signature/> as shown below:
Example 17: Recipient returns <not-acceptable/> error:
<message from='romeo@example.net/orchard' type='chat'>
<e2e xmlns='urn:ietf:params:xml:ns:xmpp-e2e'>
[CDATA section here]
</e2e>
<error type='modify'>
<not-acceptable xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'/>
<unverified-signature xmlns='urn:ietf:params:xml:xmpp-e2e'/>
</error>
</message>
In Case #5, the receiving application SHOULD return a <bad-request/>
error to the sender (as described in [XMPP-CORE]), optionally
supplemented by an application-specific error condition element
<decryption-failed/> as shown below:
Example 18: Recipient returns <bad-request/> error:
<message from='romeo@example.net/orchard' type='chat'>
<e2e xmlns='urn:ietf:params:xml:ns:xmpp-e2e'>
[CDATA section here]
</e2e>
<error type='modify'>
<bad-request xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'/>
<decryption-failed xmlns='urn:ietf:params:xml:xmpp-e2e'/>
</error>
</message>
8. Secure Communications Through a Gateway
A common method for achieving interoperability between two disparate A common method for achieving interoperability between two disparate
services is through the use of a "gateway" that interprets the services is through the use of a "gateway" that interprets the
protocols of each service and translates them into the protocols of protocols of each service and translates them into the protocols of
the other. The CPIM specifications (specifically [MSGFMT] and [PIDF] the other. The CPIM specifications (specifically [MSGFMT] and [PIDF]
define the common profiles to be used for interoperability between define the common profiles to be used for interoperability between
instant messaging and presence services that comply with [IMP-REQS]. instant messaging and presence services that comply with [IMP-REQS].
In the case of communications between an XMPP service and a non-XMPP In the case of communications between an XMPP service and a non-XMPP
service, we can visualize this relationship as follows: service, we can visualize this relationship as follows:
skipping to change at page 13, line 49 skipping to change at page 20, line 45
presence document from the non-XMPP service that is addressed to a presence document from the non-XMPP service that is addressed to a
user on the XMPP service, it MUST remove the non-XMPP "wrapper" user on the XMPP service, it MUST remove the non-XMPP "wrapper"
(if any) in order to reveal the multipart S/MIME object, wrap the (if any) in order to reveal the multipart S/MIME object, wrap the
object in an XMPP message or presence "wrapper" (including the object in an XMPP message or presence "wrapper" (including the
<e2e> and </e2e> tags), and then route the XMPP stanza to the XMPP <e2e> and </e2e> tags), and then route the XMPP stanza to the XMPP
service. service.
The wrapped S/MIME object MUST be immutable and MUST NOT be modified The wrapped S/MIME object MUST be immutable and MUST NOT be modified
by an XMPP-CPIM gateway. by an XMPP-CPIM gateway.
8. urn:ietf:params:xml:xmpp-e2e Namespace 9. urn:ietf:params:xml:xmpp-e2e Namespace
The <e2e xmlns='urn:ietf:params:xml:ns:xmpp-e2e'/> element is a The <e2e xmlns='urn:ietf:params:xml:ns:xmpp-e2e'/> element is a
wrapper for an XML CDATA section (as specified in Section 2.7 of wrapper for an XML CDATA section (see Section 2.7 of [XML]) that
[XML]) that contains a "Message/CPIM", "application/pidf+xml", or contains a "Message/CPIM", "application/pidf+xml", or "application/
"application/xmpp+xml" object. Thus the xmpp+xml" object. Thus the 'urn:ietf:params:xml:xmpp-e2e' namespace
'urn:ietf:params:xml:xmpp-e2e' namespace has no inherent semantics, has no inherent semantics, and the semantics of the encapsulated
and the semantics of the encapsulated object are defined by one of object are defined by one of the following specifications:
the following specifications:
o [MSGFMT] for "Message/CPIM" o [MSGFMT] for "Message/CPIM"
o [PIDF] for "application/pidf+xml" o [PIDF] for "application/pidf+xml"
o [XMPP-CORE] for "application/xmpp+xml" o [XMPP-CORE] for "application/xmpp+xml"
Although the "application/xmpp+xml" media type is specified in this Although the "application/xmpp+xml" media type is specified in this
document, the <xmpp/> element is simply a wrapper for a <message/>, document, the <xmpp/> element is simply a wrapper for a <message/>,
<presence/>, or <iq/> stanza, where the semantics of those stanza <presence/>, or <iq/> stanza, where the semantics of those stanza
types are specified in [XMPP-CORE]. types are specified in [XMPP-CORE].
Given that the 'urn:ietf:params:xml:ns:xmpp-e2e' namespace has no Given that the 'urn:ietf:params:xml:ns:xmpp-e2e' namespace has no
inherent semantics and specifies a using protocol only, versioning is inherent semantics and specifies a using protocol only, versioning is
the responsibility of the protocols that define the encapsulated the responsibility of the protocols that define the encapsulated
objects ([MSGFMT], [PIDF], and [XMPP-CORE]). objects ([MSGFMT], [PIDF], and [XMPP-CORE]).
9. application/xmpp+xml Media Type 10. application/xmpp+xml Media Type
The "application/xmpp+xml" media type adheres to the guidelines The "application/xmpp+xml" media type adheres to the guidelines
specified in [XML-MEDIA]. The root element for this MIME type is specified in [XML-MEDIA]. The root element for this MIME type is
<xmpp/>, and the root element MUST contain one and only one child <xmpp/>, and the root element MUST contain one and only one child
element, corresponding to one of the XMPP stanza types (i.e., element, corresponding to one of the XMPP stanza types (i.e.,
message, presence, or iq) if the default namespace is 'jabber:client' message, presence, or iq) if the default namespace is 'jabber:client'
or 'jabber:server' as defined in [XMPP-CORE]. The character encoding or 'jabber:server' as defined in [XMPP-CORE]. The character encoding
for this XML media type MUST be UTF-8, in accordance with Section for this XML media type MUST be UTF-8, in accordance with Section
11.5 of [XMPP-CORE]. 11.5 of [XMPP-CORE].
10. Security Considerations 11. Security Considerations
This entire memo discusses security. Detailed security This entire memo discusses security. Detailed security
considerations for instant messaging and presence protocols are given considerations for instant messaging and presence protocols are given
in [IMP-REQS] (Sections 5.1 through 5.4), and for XMPP in particular in [IMP-REQS] (Sections 5.1 through 5.4), and for XMPP in particular
are given in [XMPP-CORE] (Sections 12.1 through 12.6). In addition, are given in [XMPP-CORE] (Sections 12.1 through 12.6). In addition,
all of the security considerations specified in [XML-MEDIA] apply to all of the security considerations specified in [XML-MEDIA] apply to
the "application/xmpp+xml" media type. the "application/xmpp+xml" media type.
The end-to-end security method defined here MAY result in exchanging The end-to-end security method defined here MAY result in exchanging
secured instant messages and presence information through a gateway secured instant messages and presence information through a gateway
that implements the CPIM specifications. Such a gateway MUST be that implements the CPIM specifications. Such a gateway MUST be
compliant with the minimum security requirements of the instant compliant with the minimum security requirements of the instant
messaging and presence protocols with which it interfaces. messaging and presence protocols with which it interfaces.
11. IANA Considerations 12. IANA Considerations
11.1 XML Namespace Name for e2e Data in XMPP 12.1 XML Namespace Name for e2e Data in XMPP
A URN sub-namespace for signed and encrypted content in the A URN sub-namespace for signed and encrypted content in the
Extensible Messaging and Presence Protocol (XMPP) is defined as Extensible Messaging and Presence Protocol (XMPP) is defined as
follows. (This namespace name adheres to the format defined in follows. (This namespace name adheres to the format defined in
[XML-REG].) [XML-REG].)
URI: urn:ietf:params:xml:ns:xmpp-e2e URI: urn:ietf:params:xml:ns:xmpp-e2e
Specification: XXXX Specification: XXXX
Description: This is the XML namespace name for signed and encrypted Description: This is the XML namespace name for signed and encrypted
content in the Extensible Messaging and Presence Protocol as content in the Extensible Messaging and Presence Protocol as
defined by XXXX. defined by XXXX.
Registrant Contact: IESG, <iesg@ietf.org> Registrant Contact: IESG, <iesg@ietf.org>
11.2 Content-type Registration for "application/xmpp+xml" 12.2 Content-type Registration for "application/xmpp+xml"
To: ietf-types@iana.org To: ietf-types@iana.org
Subject: Registration of MIME media type application/xmpp+xml Subject: Registration of MIME media type application/xmpp+xml
MIME media type name: application MIME media type name: application
MIME subtype name: xmpp+xml MIME subtype name: xmpp+xml
Required parameters: (none) Required parameters: (none)
Optional parameters: (charset) Same as charset parameter of Optional parameters: (charset) Same as charset parameter of
application/xml as specified in RFC 3023; per Section 11.5 of application/xml as specified in RFC 3023; per Section 11.5 of
[draft-ietf-xmpp-core-24], the charset must be UTF-8. [draft-ietf-xmpp-core-24], the charset must be UTF-8.
Encoding considerations: Same as encoding considerations of Encoding considerations: Same as encoding considerations of
application/xml as specified in RFC 3023; per Section 11.5 of application/xml as specified in RFC 3023; per Section 11.5 of
[draft-ietf-xmpp-core-24], the encoding must be UTF-8. [draft-ietf-xmpp-core-24], the encoding must be UTF-8.
Security considerations: All of the security considerations specified Security considerations: All of the security considerations specified
in RFC 3023 and [draft-ietf-xmpp-core-24] apply to this XML media in RFC 3023 and [draft-ietf-xmpp-core-24] apply to this XML media
type. Refer to Section 10 of XXXX. type. Refer to Section 11 of XXXX.
Interoperability considerations: (none) Interoperability considerations: (none)
Specification: XXXX Specification: XXXX
Applications which use this media type: XMPP-compliant instant Applications which use this media type: XMPP-compliant instant
messaging and presence systems. messaging and presence systems.
Additional information: (none) Additional information: (none)
Person and email address to contact for further information: IESG, Person and email address to contact for further information: IESG,
<iesg@ietf.org> <iesg@ietf.org>
Intended usage: COMMON Intended usage: COMMON
Author/Change controller: IETF, XMPP Working Group Author/Change controller: IETF, XMPP Working Group
Normative References 13. References
[CERT] Ramsdell, B., "S/MIME Version 3 Certificate Handling", RFC 13.1 Normative References
2632, June 1999.
[CMC] Blaze, M., Ioannidis, J. and A. Keromytis, "DSA and RSA [CERT] Ramsdell, B., "S/MIME Version 3.1 Certificate Handling",
Key and Signature Encoding for the KeyNote Trust draft-ietf-smime-rfc2632bis-07 (work in progress), June
Management System", RFC 2792, March 2000. 2004.
[CMP] Adams, C. and S. Farrell, "Internet X.509 Public Key [CMS] Housley, R., "Cryptographic Message Syntax (CMS)",
Infrastructure Certificate Management Protocols", RFC draft-ietf-smime-rfc3369bis-04 (work in progress), May
2510, March 1999. 2004.
[CMS] Housley, R., "Cryptographic Message Syntax (CMS)", RFC [CMS-AES] Schaad, J., "Use of the Advanced Encryption Standard (AES)
3369, August 2002. Encryption Algorithm in Cryptographic Message Syntax
(CMS)", RFC 3565, July 2003.
[CMS-ALG] Housley, R., "Cryptographic Message Syntax (CMS) [CMS-ALG] Housley, R., "Cryptographic Message Syntax (CMS)
Algorithms", RFC 3370, August 2002. Algorithms", RFC 3370, August 2002.
[CPIM] Crocker, D. and J. Peterson, "Common Profile for Instant [CPIM] Peterson, J., "Common Profile for Instant Messaging
Messaging (CPIM)", draft-ietf-impp-im-03 (work in (CPIM)", draft-ietf-impp-im-04 (work in progress),
progress), May 2003. February 2004.
[CPP] Crocker, D. and J. Peterson, "Common Profile for Presence [CPP] Peterson, J., "Common Profile for Presence (CPP)",
(CPP)", draft-ietf-impp-pres-03 (work in progress), May draft-ietf-impp-pres-04 (work in progress), February 2004.
2003.
[DATETIME] [DATETIME]
Klyne, G. and C. Newman, "Date and Time on the Internet: Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, July 2002. Timestamps", RFC 3339, July 2002.
[DISP] Troost, R., Dorner, S. and K. Moore, "Communicating [DISP] Troost, R., Dorner, S. and K. Moore, "Communicating
Presentation Information in Internet Messages: The Presentation Information in Internet Messages: The
Content-Disposition Header Field", RFC 2183, August 1997. Content-Disposition Header Field", RFC 2183, August 1997.
[IMP-MODEL] [IMP-MODEL]
skipping to change at page 17, line 4 skipping to change at page 23, line 43
[MSGFMT] Atkins, D. and G. Klyne, "Common Presence and Instant [MSGFMT] Atkins, D. and G. Klyne, "Common Presence and Instant
Messaging: Message Format", draft-ietf-impp-cpim-msgfmt-08 Messaging: Message Format", draft-ietf-impp-cpim-msgfmt-08
(work in progress), January 2003. (work in progress), January 2003.
[MULTI] Galvin, J., Murphy, S., Crocker, S. and N. Freed, [MULTI] Galvin, J., Murphy, S., Crocker, S. and N. Freed,
"Security Multiparts for MIME: Multipart/Signed and "Security Multiparts for MIME: Multipart/Signed and
Multipart/Encrypted", RFC 1847, October 1995. Multipart/Encrypted", RFC 1847, October 1995.
[PIDF] Fujimoto, S., Sugano, H., Klyne, G., Bateman, A., Carr, W. [PIDF] Fujimoto, S., Sugano, H., Klyne, G., Bateman, A., Carr, W.
and J. Peterson, "Presence Information Data Format", and J. Peterson, "Presence Information Data Format",
draft-ietf-impp-cpim-pidf-08 (work in progress), May 2003. draft-ietf-impp-cpim-pidf-08 (work in progress), May 2003.
[SMIME] Ramsdell, B., "S/MIME Version 3 Message Specification", [SMIME] Ramsdell, B., "S/MIME Version 3.1 Message Specification",
RFC 2633, June 1999. draft-ietf-smime-rfc2633bis-09 (work in progress), April
2004.
[TERMS] Bradner, S., "Key words for use in RFCs to Indicate [TERMS] 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.
[X509] Housley, R., Polk, W., Ford, W. and D. Solo, "Internet [X509] 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. April 2002.
[XML] Bray, T., Paoli, J., Sperberg-McQueen, C. and E. Maler,
"Extensible Markup Language (XML) 1.0 (2nd ed)", W3C
REC-xml, October 2000, <http://www.w3.org/TR/REC-xml>.
[XML-MEDIA] [XML-MEDIA]
Murata, M., St. Laurent, S. and D. Kohn, "XML Media Murata, M., St. Laurent, S. and D. Kohn, "XML Media
Types", RFC 3023, January 2001. Types", RFC 3023, January 2001.
[XMPP-CORE] [XMPP-CORE]
Saint-Andre, P., "XMPP Core", draft-ietf-xmpp-core-24 Saint-Andre, P., "XMPP Core", draft-ietf-xmpp-core-24
(work in progress), May 2004. (work in progress), May 2004.
[XMPP-IM] Saint-Andre, P., "XMPP Instant Messaging", [XMPP-IM] Saint-Andre, P., "XMPP Instant Messaging",
draft-ietf-xmpp-im-22 (work in progress), May 2004. draft-ietf-xmpp-im-22 (work in progress), May 2004.
Informative References 13.2 Informative References
[CAPS] Hildebrand, J. and P. Saint-Andre, "JEP-0115: Entity
Capabilities", April 2004,
<http://www.jabber.org/jeps/jep-0115.html>.
[CMC] Myers, M., Liu, X., Schaad, J. and J. Weinstein,
"Certificate Management Messages over CMS", RFC 2797,
April 2000.
[CMP] Adams, C. and S. Farrell, "Internet X.509 Public Key
Infrastructure Certificate Management Protocols", RFC
2510, March 1999.
[DISCO] Hildebrand, J., Millard, P., Eatmon, R. and P.
Saint-Andre, "JEP-0030: Service Discovery", June 2004,
<http://www.jabber.org/jeps/jep-0030.html>.
[MUC] Saint-Andre, P., "JEP-0045: Multi-User Chat", June 2004,
<http://www.jabber.org/jeps/jep-0045.html>.
[XML] Bray, T., Paoli, J., Sperberg-McQueen, C. and E. Maler,
"Extensible Markup Language (XML) 1.0 (3rd ed)", W3C
REC-xml, February 2004, <http://www.w3.org/TR/REC-xml>.
[XML-REG] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, [XML-REG] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004. January 2004.
[XMPP-CPIM] [XMPP-CPIM]
Saint-Andre, P., "Mapping the Extensible Messaging and Saint-Andre, P., "Mapping the Extensible Messaging and
Presence Protocol (XMPP) to Common Presence and Instant Presence Protocol (XMPP) to Common Presence and Instant
Messaging (CPIM)", draft-ietf-xmpp-cpim-05 (work in Messaging (CPIM)", draft-ietf-xmpp-cpim-05 (work in
progress), May 2004. progress), May 2004.
skipping to change at page 18, line 19 skipping to change at page 25, line 27
<?xml version='1.0' encoding='UTF-8'?> <?xml version='1.0' encoding='UTF-8'?>
<xs:schema <xs:schema
xmlns:xs='http://www.w3.org/2001/XMLSchema' xmlns:xs='http://www.w3.org/2001/XMLSchema'
targetNamespace='urn:ietf:params:xml:ns:xmpp-e2e' targetNamespace='urn:ietf:params:xml:ns:xmpp-e2e'
xmlns='urn:ietf:params:xml:ns:xmpp-e2e' xmlns='urn:ietf:params:xml:ns:xmpp-e2e'
elementFormDefault='qualified'> elementFormDefault='qualified'>
<xs:element name='e2e' type='xs:string'/> <xs:element name='e2e' type='xs:string'/>
<xs:element name='decryption-failed' type='empty'/>
<xs:element name='signature-unverified' type='empty'/>
<xs:element name='bad-timestamp' type='empty'/>
<xs:simpleType name='empty'>
<xs:restriction base='xs:string'>
<xs:enumeration value=''/>
</xs:restriction>
</xs:simpleType>
</xs:schema> </xs:schema>
Appendix B. Revision History Appendix B. Revision History
Note to RFC Editor: please remove this entire appendix, and the Note to RFC Editor: please remove this entire appendix, and the
corresponding entries in the table of contents, prior to publication. corresponding entries in the table of contents, prior to publication.
B.1 Changes from draft-ietf-xmpp-e2e-07 B.1 Changes from draft-ietf-xmpp-e2e-08
o Changed title to mention signing in addition to encryption.
o Specified several functionality areas that are out of scope for
this memo.
o Added clarifying text to the examples, split several examples in
order to correspond to the defined process steps, and added
examples for encrypting both messages and presence information.
o Changed SHOULD to MUST regarding checking of XMPP addresses.
o Changed "could" to SHOULD regarding sending of initial message
requesting certificate retrieval.
o Specified that 'from' attributes MUST (rather than SHOULD) match a
JID contained in the sender's certificate, and that resource
identifiers SHOULD be ignored for matching purposes.
o More fully defined S/MIME handling, including correct processing
of XML stanzas with invalid signatures, stanzas that cannot be
decrypted, and messages that appear to be replayed.
o Defined recipient generation of XMPP error stanzas.
o Incorporated text for "Mandatory-to-Implement Cryptographic
Algorithms" suggested by Russ Housley.
o Referred to Section 5.1.1 of XMPP-CORE regarding ASN.1 Object
Identifier to be used when an XMPP address is represented in a
certificate.
o Added reference to RFC 3565.
o Fixed CMC reference to point to RFC 2797.
o Updated references to point to rfc2632bis, rfc2633bis, and
rfc3369bis.
o Updated boilerplate to refer to RFC 3668.
o Removed Discussion Venue subsection.
B.2 Changes from draft-ietf-xmpp-e2e-07
o Clarified relationship of the 'urn:ietf:params:xml:ns:xmpp-e2e' o Clarified relationship of the 'urn:ietf:params:xml:ns:xmpp-e2e'
namespace to its encapsulated objects, including versioning, and namespace to its encapsulated objects, including versioning, and
placed this content in its own section. placed this content in its own section.
o Clarified nature of "application/xmpp+xml" media type and placed o Clarified nature of "application/xmpp+xml" media type and placed
this content in its own section. this content in its own section.
o Added reference to RFC 3023 and modified XML media type o Added reference to RFC 3023 and modified XML media type
registration to adhere to the guidelines specified therein. registration to adhere to the guidelines specified therein.
o Changed XML params registrant to IESG, per RFC 3688. o Changed XML params registrant to IESG, per RFC 3688.
o Updated other references. o Updated other references.
B.2 Changes from draft-ietf-xmpp-e2e-06 B.3 Changes from draft-ietf-xmpp-e2e-06
o Specified use of SHA-1 for digest and AES for content encryption. o Specified use of SHA-1 for digest and AES for content encryption.
o Specified order of signing then encrypting. o Specified order of signing then encrypting.
o Specified format and checking of timestamps. o Specified format and checking of timestamps.
o Clarified use of subjectAltName field, where the GeneralName o Clarified use of subjectAltName field, where the GeneralName
content is a URI of the form im:user@host and pres:user@host. content is a URI of the form im:user@host and pres:user@host.
o Clarified circumstances under which certificates should be o Clarified circumstances under which certificates should be
attached. attached.
o Added Content-Disposition header field to examples. o Added Content-Disposition header field to examples.
B.3 Changes from draft-ietf-xmpp-e2e-05 B.4 Changes from draft-ietf-xmpp-e2e-05
o Addressed I-D nits and RFC Editor formatting. o Addressed I-D nits and RFC Editor formatting.
B.4 Changes from draft-ietf-xmpp-e2e-04 B.5 Changes from draft-ietf-xmpp-e2e-04
o Added text about instant inbox addresses. o Added text about instant inbox addresses.
B.5 Changes from draft-ietf-xmpp-e2e-03 B.6 Changes from draft-ietf-xmpp-e2e-03
o Specified that S/MIME multipart objects are enclosed in a CDATA o Specified that S/MIME multipart objects are enclosed in a CDATA
section. section.
o Changed "text/xml" to "text/plain" for message examples. o Changed "text/xml" to "text/plain" for message examples.
o Specified must-implement technologies, transfer encodings, o Specified must-implement technologies, transfer encodings,
certificate enrollment, certificate retrieval, and certificate certificate enrollment, certificate retrieval, and certificate
names (including subjectAltName for JIDs). names (including subjectAltName for JIDs).
o Specified requirements regarding attachment of signatures and o Specified requirements regarding attachment of signatures and
inclusion of certificates. inclusion of certificates.
o Fixed some small terminological errors. o Fixed some small terminological errors.
B.6 Changes from draft-ietf-xmpp-e2e-02 B.7 Changes from draft-ietf-xmpp-e2e-02
o Completely revised to use formats defined in the CPIM o Completely revised to use formats defined in the CPIM
specifications, S/MIME only, etc. specifications, S/MIME only, etc.
B.7 Changes from draft-ietf-xmpp-e2e-01 B.8 Changes from draft-ietf-xmpp-e2e-01
o Removed old Section 6 (Signalling Support via Presence) -- the o Removed old Section 6 (Signalling Support via Presence) -- the
ability to sign broadcasted presence made it redundant. ability to sign broadcasted presence made it redundant.
o Made small editorial changes to address RFC Editor requirements. o Made small editorial changes to address RFC Editor requirements.
B.8 Changes from draft-ietf-xmpp-e2e-00 B.9 Changes from draft-ietf-xmpp-e2e-00
o Added support for all stanza types. o Added support for all stanza types.
o Specified that the full stanza is encrypted. o Specified that the full stanza is encrypted.
o Added support for S/MIME in addition to OpenPGP. o Added support for S/MIME in addition to OpenPGP.
o Specified that encrypted presence must be directed to a specific o Specified that encrypted presence must be directed to a specific
recipient. recipient.
o Specified order of encrypting and signing. o Specified order of encrypting and signing.
o Added support for signing broadcasted presence. o Added support for signing broadcasted presence.
o Added IANA considerations. o Added IANA considerations.
o Changed namespace to 'urn:ietf:params:xml:ns:xmpp-e2e'. o Changed namespace to 'urn:ietf:params:xml:ns:xmpp-e2e'.
o Added XML schema. o Added XML schema.
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standards-related documentation can be found in BCP-11. Copies of found in BCP 78 and BCP 79.
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Acknowledgment Acknowledgment
Funding for the RFC Editor function is currently provided by the Funding for the RFC Editor function is currently provided by the
Internet Society. Internet Society.
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