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12 13 14 15 RFC 4567
Internet Engineering Task Force J. Arkko
MMUSIC Working Group E. Carrara
INTERNET-DRAFT F. Lindholm
Expires: April 2004 M. Naslund
K. Norrman
Ericsson
October 2003
Key Management Extensions for Session Description
Protocol (SDP) and Real Time Streaming Protocol (RTSP)
<draft-ietf-mmusic-kmgmt-ext-09.txt>
Status of this memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
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Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract
This document defines general extensions for SDP and RTSP to carry
messages as specified by a key management protocol, in order to
secure the media. These extensions are presented as a framework, to
be used by one or more key management protocols. As such, its use is
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meaningful only when it is completed by the key management protocol
in use.
General guidelines are also given on how the framework should be used
together with SIP and RTSP.
TABLE OF CONTENTS
1. Introduction.....................................................2
1.1. Notational Conventions.........................................3
2. Extensions to SDP and RTSP.......................................4
2.1. SDP Extensions.................................................4
2.2. RTSP Extensions................................................5
3. Usage with SIP and RTSP..........................................5
3.1. General SDP processing.........................................6
3.2. SIP usage......................................................7
3.3. RTSP usage.....................................................8
3.4. Bidding-down attack prevention.................................9
3.5. Example scenarios.............................................10
4. Adding further Key management protocols.........................13
5. Security Considerations.........................................13
6. IANA Considerations.............................................14
6.1. SDP Attribute Registration....................................14
6.2. RTSP Header Registration......................................15
6.3. Protocol Identifier Registration..............................15
7. Acknowledgments.................................................16
8. Author's Addresses..............................................16
9. References......................................................17
9.1. Normative References..........................................17
9.2. Informative References........................................17
1. Introduction
[Editor remark] All instances of RFC xxxx should be replaced with
the RFC number of this document, when published. Furthermore, all
instances of RFC yyyy should be replaced with the RFC number of
the MIKEY (Multimedia Internet KEYing) document [MIKEY], when
published.
There has recently been work to define a security framework for the
protection of real-time applications running over RTP, [SRTP].
However, a security protocol needs a key management solution to
exchange keys and security parameters, manage and refresh keys, etc.
A key management protocol is executed prior to the security protocol
execution. The key management protocol's main goal is to, in a secure
and reliable way, establish a security association for the security
protocol. This includes one or more cryptographic keys and the set of
necessary parameters for the security protocol, e.g., cipher and
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authentication algorithm to be used. The key management protocol has
similarities with, e.g., SIP [SIP] and RTSP [RTSP] in the sense that
it negotiates necessary information in order to be able to setup the
session.
The focus in the following sections is to describe a new SDP
attribute and RTSP header extension to support key management, and
the integration within SIP and RTSP. A framework is therefore
described in the following. This framework is completed by one or
more key management protocols, to describe how the framework is used,
e.g. which is the data to be carried in the extensions.
Some of the motivations to create a framework with the possibility to
include the key management in the session establishment are:
* Just as the codec information is a description of how to encode and
decode the audio (or video) stream, the key management data is a
description of how to encrypt and decrypt the data.
* The possibility to negotiate the security for the entire multimedia
session at the same time.
* The knowledge of the media at the session establishment makes it
easy to tie the key management to the multimedia sessions.
* This approach may be more efficient than setting up the security
later, as that approach might force extra roundtrips, possibly
also a separate set-up for each stream, hence implying more delay
to the actual setup of the media session.
* The possibility to negotiate keying material end-to-end without
applying end-to-end protection of the SDP (instead, hop-by-hop
security mechanisms can be used which may be useful if
intermediate proxies needs access to the SDP).
Currently in SDP [SDPnew], one field exists to transport keys, i.e.
the "k=" field. However, this is not enough for a key management
protocol as there are many more parameters that need to be
transported. The approach here is to use and extend the SDP
description to transport the key management offer/answer and also to
associate it with the media sessions. SIP uses the offer/answer model
[OAM] whereby extensions to SDP will be enough. However, RTSP [RTSP]
does not use the offer/answer model with SDP, so a new header is
introduced to convey key management data.
1.1. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
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2. Extensions to SDP and RTSP
This section describes common attributes that are to be included in
an SDP description or in an RTSP header when an integrated key
management protocol is used. The attribute values MUST follow the
general SDP or RTSP guidelines (see [SDPnew] and [RTSP]).
For both SDP and RTSP, the general method of adding the key
management protocol is to introduce new attributes, one identifier to
identify the specific key management protocol, and one data field
where the key management protocol data is placed. The key management
protocol data contains the necessary information to establish the
security protocol, e.g., keys and cryptographic parameters. All
parameters and keys are protected by the key management protocol.
The key management data SHALL be base64 encoded and comply with the
base64 grammar as defined in [SDPnew]. The key management protocol
identifier, KMID, is defined as below (where ALPHA and DIGIT are as
defined in [RFC2234]).
KMID = 1*(ALPHA/DIGIT)
Values for the identifier, KMID, are registered and defined in
accordance to Section 6. Note that the KMID will be case sensitive
and it is therefore RECOMMENDED that values registered are lower case
letters.
2.1. SDP Extensions
This section provides an Augmented Backus-Naur Form (ABNF) grammar
(as used in [SDPnew]) for the key management extensions to SDP.
Note that the new definitions are compliant with the definition of an
attribute field, i.e.
attribute = (att-field ":" att-value) | att-field
One new attribute for SDP is defined:
key-mgmt = "key-mgmt: " prtcl-id keymgmt-data
prtcl-id = KMID
; e.g. "mikey"
keymgmt-data = text
where KMID is as previously defined, "text" is as defined in SDP
[SDPnew]. Prtcl-id refers to the set of values defined for KMID in
Section 6. "text" is consistent with the requirement of base64-
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encoded data, and KMID is consistent with the standard definition of
non-ws-string.
The attribute may be used at session level, media level, or at both
levels. An attribute defined at media level overrides an attribute
defined at session level. Section 3 describes in detail how the
attributes are used and how the SDP is handled in different usage
scenarios.
2.2. RTSP Extensions
To support the needed attribute, the following RTSP header is
defined:
KeyMgmt = "keymgmt" ":" 1#key-mgmt-spec
key-mgmt-spec = "prot" "=" KMID ";" "data" "=" quoted-string
where KMID is as previously defined and "quoted-string" as defined in
the RTSP specification [RTSP]. "quoted-string" is consistent with the
requirement of base64-encoded data, and KMID is consistent with the
standard definition of token.
The KeyMgmt header should be possible to use in the messages
described in the table below.
Method Direction Requirement
DESCRIBE C->S optional
SETUP C->S required
ANNOUNCE C->S, S->C optional (required: if re-key is supported)
Note: Section 3 describes in detail how the RTSP extensions are used.
3. Usage with SIP and RTSP
This section gives recommendations of how/when to include the defined
key management attribute when SIP and/or RTSP are used together with
SDP.
When a key management protocol is integrated with SIP/SDP and RTSP,
the following requirements are placed on the key management:
* It MUST be possible to execute the key management protocol in at
most one roundtrip in case the answerer accepts the offer.
* It MUST be possible from the SIP/SDP and RTSP application, using
the key management API, to receive key management data, and
information of whether a message is accepted or not.
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Today, the MIKEY protocol [MIKEY] has adopted the key management
extensions to work together with SIP and RTSP. Other protocols MAY
use the described attribute and header, e.g. Kerberos [KERB], however
this is subject to future standardization.
3.1. General SDP processing
When an SDP message is created, the following procedure SHALL be
applied:
* The identifier of the key management protocol used MUST be placed
in the prtcl-id field. The protocol identifier values are
specified by IANA (see Section 6).
* The list of protocol identifiers is provided by the SDP application
to (each) key management protocol, as defined in Section 3.4. (to
defeat bidding-down attacks).
* The keymgmt-data field MUST be created as follows. The key
management protocol MUST be used to create the key management
message. This message SHALL be base64 encoded [RFC3548] by the SDP
application and then encapsulated in the keymgmt-data attribute.
The data may e.g. be a MIKEY message (see [MIKEY], Section 7).
A received SDP message that contains the key management attributes
SHALL be processed in the following manner:
* The key management protocol is identified according to the prtcl-id
field. The protocol identifier values are specified by IANA
(Section 6).
* The key management data from the keymgmt-data field MUST be
extracted, base64 decoded to reconstruct the original message, and
then passed to the key management protocol.
* The list of protocol identifiers is provided by the SDP application
to the key management protocol, as defined in Section 3.4. Note
that depending on key management protocol, some extra parameters
might also be requested by the specific API, such as the
source/destination network address/port(s) for the specified media
(however, this will be implementation specific depending on the
actual API). The extra parameters that a key management protocol
might need (other than the ones defined here) SHOULD be
documented, describing their use, as well as the interaction of
that key management protocol with SDP and RTSP.
* If the key management processing is successful, then the answerer
sends back the answer. Otherwise, if the key management rejects
the offer, an error is sent back ("606 Not Acceptable") and the
session is aborted. See Section 3.2 for further details.
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Note that the key management attribute MAY be repeated more than once
(e.g., one at session level and one at media level). Consequently,
the process is repeated for each key management attribute detected.
However, in case of failure of the key management (on either session
or media level), the session setup SHALL be aborted (see also Section
3.2 and Section 3.3 for more details).
In the Offer/Answer case, and in general when there is an answer, if
more than one key management protocol is supported, multiple
instances of the key management attribute MAY be included in the
initial offer, each transporting a different key management data,
thus indicating supported alternatives.
If the sender includes more than one key management protocol
attribute at session level (analogous for the media level), these
SHOULD be listed in order of preference (the first being the
preferred). The receiver selects the key management protocol it
wishes to use and includes only that attribute in the answer. If the
receiver does not support any of the sender's suggested key
management protocols, the receiver returns an error message (see
section 3.2 and section 3.3), whereby the sender MUST abort the
current setup procedure.
Note that the placement of multiple key management offers in a single
message has the disadvantage that the message expands and the
computational workload for the offerer will increase drastically.
Unless the guidelines of Section 3.4 are followed, multiple lines may
open up for bidding-down attacks.
The following Sections describe the specific use with SIP and RTSP
respectively. There are of course other cases where SDP is used, such
as SAP and HTTP. If SDP is transported in an Offer-Answer model
fashion, then the guidelines in Section 3.2 can be used. However, for
one-way SDP distribution (i.e. without back channel), the above
guidelines can be used though with certain restrictions. First, the
key management protocol MUST support one-way messages, and secondly,
only one key management protocol SHALL be offered (i.e. no
negotiation will be possible).
This document does NOT address one-to-many distribution scenarios, as
this would require different types of key management protocols. The
support for such scenarios is for future standardization.
3.2. SIP usage
When used with SIP and the offer/answer model, the offerer SHOULD
include the key management data within an offer that contains the
media description it should apply to. At the answerer's side, the key
management protocol checks the validity of the key management
message, together with the availability of the offered attribute
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values, and then provides the key management data to be included in
the answer.
If the offer is not accepted, the answerer SHOULD return a "606 Not
Acceptable" message, including one or more Warning headers (e.g. a
306 "Attribute not understood" when one of the parameters is not
supported). The session is then aborted (and it is up to local policy
or end user to decide how to continue).
Re-keying can be handled as a new offer, i.e. a re-INVITE should be
sent with the new proposed parameters. The answerer treats this as a
new offer where the key management is the issue of change. In
general, the re-INVITE (and the key exchange) must be finalized
before the security protocol can change the keys. The same key
management protocol used in the original INVITE SHALL also be used in
the re-INVITE carrying re-keying. If the re-INVITE carrying re-keying
fails (e.g., the authentication verification fails), the answerer
SHOULD send a "606 Not Acceptable" message, including one or more
Warning headers (at least a 306). The offerer MUST then abort the
security setup.
3.3. RTSP usage
RTSP does not use the offer/answer model, as SIP does. This causes
some problems, as it is not possible (without abusing RTSP) to send
back an answer to the server (as the server will in most cases be the
one initiating the security parameter exchange). To solve this, a new
header has been introduced (Section 2.2). This also assumes that the
key management also has some kind of binding to the media, so that
the response to the server will be processed as required.
To obtain a session description, the client initially contacts the
server via a DESCRIBE message (according to RTSP, a media description
could also be obtained by other means e.g. using http). The initial
key management message from the RTSP server is sent to the client in
the SDP of the 200 OK in response to the DESCRIBE. When responding to
this, the client uses the new RTSP header to send back an answer
(included in the SETUP message). If a server receives a SETUP message
in which it expects a key management message, but none is included, a
403 Forbidden SHOULD be returned to the client, whereby the current
setup MUST be aborted.
The processing of creating a key management header in RTSP SHALL be
as follow:
* The identifier of the key management protocol used (e.g. MIKEY)
MUST be placed in the "prot" field of the header. The prot values
are specified by IANA (Section 6).
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* The list of protocol identifiers is sent by the RTSP application to
(each) key management protocol as described in Section 3.4. (to
defeat bidding-down attacks).
* The keymgmt-data field MUST be created as follows. The key
management protocol MUST be used to create the key management
message. This message SHALL be base64 encoded by the SDP
application and then encapsulated in the "data" field of the
header. The data may e.g. be a MIKEY message (see [MIKEY], Section
7).
A received key management header SHALL be processed in the following
manner:
* The key management protocol is identified according to the "prot"
field.
* The key management data from the "data" field MUST be extracted,
base64 decoded to reconstruct the original message, and then
passed to the key management protocol. Note that depending on the
key management protocol, some extra parameters might of course be
requested by the specific API, such as the source/destination
network address/port(s) for the specified media (however, this
will be implementation specific depending on the actual API).
* Depending on the outcome of the key management processing (i.e.
whether it was successful or not), the processing can proceed
according to normal rules (see also below).
The server MAY provide re-keying/updating facilities by sending a new
key management message in an ANNOUNCE message. The ANNOUNCE message
contains an SDP message including the key management parameters. The
response message is put in the new RTSP header in the response from
the client to the server. Note that the ANNOUNCE messages MUST be
supported if this feature is to be used.
3.4. Bidding-down attack prevention
The possibility to support multiple key management protocols may,
unless properly handled, introduce so-called bidding-down attacks.
Specifically, a man-in-the-middle could "peel off" cryptographically
strong offers (deleting key-mgmt lines from the message), leaving
only weaker ones as the responderÆs choice. To avoid this, the list
of identifiers of the proposed key management protocols MUST be
authenticated. The authentication MUST be done separately by each key
management protocol (see e.g. Section 7.1 in [MIKEY]).
Accordingly, it MUST be specified (in the key management protocol
specification itself or in a companion document) how the list of key
management protocol identifiers can be processed to be authenticated
from the offerer to the answerer by the specific key management
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protocol. Note that even if only one key management protocol is used,
that still MUST authenticate its own protocol identifier.
The list of protocol identifiers MUST then be given to each of the
selected (offered) key management protocols by the application with
";" separated identifiers. All the offered protocol identifiers MUST
be included, in the same order as they appear in the corresponding
SDP description.
The protocol list can formally be described as
prtcl-list = KMID *(";" KMID)
where KMID is as defined in Section 2.
For example, if the offered protocols are MIKEY and two yet-to-be-
invented protocols KEYP1, KEYP2, the SDP is:
v=0
o=alice 2891092738 2891092738 IN IP4 lost.example.com
s=Secret discussion
t=0 0
c=IN IP4 lost.example.com
a=key-mgmt:mikey <data1>
a=key-mgmt:keyp1 <data2>
a=key-mgmt:keyp2 <data3>
m=audio 39000 RTP/SAVP 98
a=rtpmap:98 AMR/8000
m=video 42000 RTP/SAVP 31
a=rtpmap:31 H261/90000
The protocol list, "mikey;keyp1;keyp2", would be generated from
the SDP description and used as input to each specified key
management protocol (together with the data for that protocol).
Each of the three protocols includes this protocol identifier
list in its authentication coverage (according to its protocol
specification).
If more than one protocol are supported by the offerer, it is
RECOMMENDED that all acceptable protocols are included in the first
offer, rather than making single, subsequent alternative offers in
response to error messages, see "Security Considerations".
3.5. Example scenarios
Example 1 (SIP)
A SIP call is taking place between Alice and Bob. Alice sends an
Invite message consisting of the following offer:
v=0
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o=alice 2891092738 2891092738 IN IP4 w-land.example.com
s=Cool stuff
e=alice@w-land.example.com
t=0 0
c=IN IP4 w-land.example.com
a=key-mgmt:mikey uiSDF9sdhs727ghsd/dhsoKkdOokdo7eWsnDSJD...
m=audio 49000 RTP/SAVP 98
a=rtpmap:98 AMR/8000
m=video 52230 RTP/SAVP 31
a=rtpmap:31 H261/90000
i.e. Alice proposes to set up one audio stream and one video stream
that run over SRTP. To set up the security parameters for SRTP, she
uses MIKEY. Note that MIKEY is negotiating the crypto suite for both
streams (as it is placed at the session level).
Bob accepts the offer and sends an answer back to Alice:
v=0
o=bob 2891092897 2891092897 IN IP4 foo.example.com
s=Cool stuff
e=bob@foo.example.com
t=0 0
c=IN IP4 foo.example.com
a=key-mgmt:mikey skaoqDeMkdwRW278HjKVB...
m=audio 49030 RTP/SAVP 98
a=rtpmap:98 AMR/8000
m=video 52230 RTP/SAVP 31
a=rtpmap:31 H261/90000
Example 2 (SDP)
This example shows how Alice would have done if she wished to protect
only the audio stream.
v=0
o=alice 2891092738 2891092738 IN IP4 w-land.example.com
s=Cool stuff
e=alice@w-land.example.com
t=0 0
c=IN IP4 w-land.example.com
m=audio 49000 RTP/SAVP 98
a=rtpmap:98 AMR/8000
a=key-mgmt:mikey uiSDF9sdhs727ghsd/dhsoKkdOokdo7eWsnDSJD...
m=video 52230 RTP/AVP 31
a=rtpmap:31 H261/90000
Note that even if the key management attribute were specified at
session level, the video part would not be affected by this (as a
security profile is not used).
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Example 3 (RTSP)
A client wants to set up a streaming session and requests a media
description from the streaming server.
DESCRIBE rtsp://server.example.com/fizzle/foo RTSP/1.0
CSeq: 312
Accept: application/sdp
From: user@example.com
The server sends back an OK message including an SDP description.
RTSP/1.0 200 OK
CSeq: 312
Date: 23 Jan 1997 15:35:06 GMT
Content-Type: application/sdp
v=0
o=actionmovie 2891092738 2891092738 IN IP4 movie.example.com
s=Action Movie
e=action@movie.example.com
t=0 0
c=IN IP4 movie.example.com
a=key-mgmt:mikey uiSDF9sdhs727ghsd/dhsoKkdOokdo7eWsnDSJD...
m=audio 0 RTP/SAVP 98
a=rtpmap:98 AMR/8000
control:rtsp://movie.example.com/action/audio
m=video 0 RTP/SAVP 31
a=rtpmap:31 H261/90000
control:rtsp://movie.example.com/action/video
The client is now ready to setup the sessions. It includes the key
management data in the first message going back to the server (i.e.
the SETUP message).
SETUP rtsp://movie.example.com/action/audio RTSP/1.0
CSeq: 313
Transport: RTP/SAVP/UDP;unicast;client_port=3056-3057
keymgmt: prot=mikey; data="skaoqDeMkdwRW278HjKVB..."
The server processes the request including checking the validity of
the key management header.
RTSP/1.0 200 OK
CSeq: 313
Session: 12345678
Transport: RTP/SAVP/UDP;unicast;client_port=3056-3057;
server_port=5000-5001
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The RTSP then proceeds as usual (with e.g. a SETUP message for the
video followed by a PLAY message).
4. Adding further Key management protocols
This framework cannot be used with all key management protocols. The
key management protocol needs to comply with the requirements
described in Section 3. In addition to this, the following needs to
be defined:
* The key management protocol identifier to be used as the protocol
identifier should be registered at IANA according to Section 6
(e.g. "mikey" for MIKEY).
* The information that the key management needs from SDP and RTSP,
and vice versa, as described in Section 3. The exact API is
implementation specific, but it SHOULD at least support to
exchange the specified information.
* The key management protocol to be added MUST be such, that the
processing in Section 3 (describing its interactions with SDP and
RTSP) can be applied. Note in particular, Section 3.4 requires
each key management protocol to specify how the list of protocol
identifiers is authenticated inside that key management protocol.
The key management MUST always be given the protocol identifier(s)
of the key management protocol(s) included in the offer in the
correct order as they appear.
Finally, it is obviously crucial to analyze possible security
implications induced by the introduction of a new key management
protocol in the described framework.
5. Security Considerations
As a general practice, it is a good thing, not only to try to secure
the session, but also to secure the session setup. However, the
security of the session setup might not possible on an end-to-end
basis, but the setup may require to be protected on a hop-by-hop
basis (this is generally the case for SIP/SDP when intermediate
proxies needs to obtain information about the sessions etc, c.f.
[E2M]). In fact, the focus of this framework is mainly when end-to-
end protection of the session setup is not used, but where the media
streams needs to be end-to-end protected. General security
considerations for the session setup can be found in SDP [SDPnew],
SIP [SIP], and RTSP [RTSP].
The security will also depend on the encapsulated level of security
the key management protocol offers. It follows that, under the
assumption that the key management schemes are secure, the SDP can be
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passed along unprotected without affecting the key management as
such, and the media streams will still be secure even if some
attackers gained knowledge of the SDP contents. Further security
considerations can be found for each key management protocol (for
MIKEY these can be found in [MIKEY]).
However, if the SDP messages are not sent authenticated between the
parties, it is possible for an active attacker to change attributes
without being detected. As the key management protocol may
(indirectly) rely on some of the session information from SDP (e.g.,
address information), an attack on SDP may have indirect consequences
on the key management. Even if the key management protocol does not
rely on parameters of SDP and will not be affected by manipulation of
these, different DoS attacks aimed at SDP (e.g. the SIMCAP
extensions) may lead to undesired interruption in the setup.
The use of multiple key management protocols in the same offer may
open up the possibility of a bidding-down attack, as specified in
Section 3.4. To exclude such possibility, the authentication of the
protocol identifier list is used. Note though, that the security
level of the authenticated protocol identifier will be as high (or
low), as the "weakest" protocol. Therefore, it is discouraged to
offer protocols with too different security levels.
Note that it is impossible to assure the authenticity of a declined
offer, since even if it comes from the true respondent, the fact that
the answerer declines the offer usually means that he does not
support the protocol(s) offered, and consequently cannot be expected
to authenticate the response either. This means that if the initiator
is unsure of which protocol(s) the responder supports, we RECOMMEND
that the initiator offers all acceptable protocols in a single offer.
If not, this opens up the possibility for a "man-in-the-middle"
(MITM) to affect the outcome of the eventually agreed upon protocol,
by faking unauthenticated error messages until the initiator
eventually offers a protocol "to the liking" of the MITM. This is not
really a security problem, but rather a mild form of denial of
service that can be avoided by following the above recommendation. In
the case that the response declines any security (therefore there is
impossibility of authenticating it), the session setup SHALL be
aborted.
6. IANA Considerations
6.1. SDP Attribute Registration
A new SDP attribute needs to be registered for the purpose of key
management protocol integration with SDP.
Contact: Fredrik Lindholm
mailto: fredrik.lindholm@ericsson.com
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tel: +46 8 58531705
SDP Attribute ("att-field"):
Name: key-mgmt
Long form: key management protocol
Type of name: att-field
Type of attribute: Media and session level
Purpose: See RFC xxxx, Section 2.
Reference: RFC xxxx, Section 2.1
Values: See Section 6.3
6.2. RTSP Header Registration
A new RTSP Header needs to be registered for the purpose of key
management protocol integration with RTSP.
Following the guidelines of [RTSP], the registration is defined as
follows:
Header name: keymgmt
Header syntax: see RFC xxxx, Section 2.2
Intended usage: see RFC xxxx, Section 2.2
Proxy treatment: Proxies SHOULD forward the header
Purpose: see RFC xxxx, Section 2
6.3. Protocol Identifier Registration
This document defines one new name space associated with the protocol
identifier, KMID, defined in Section 2 to be used with the above
registered key-mgmt attributes in SDP and RTSP.
A new registry needs to be set up for the KMID parameter, with the
following registration created initially: "mikey".
Contact: Fredrik Lindholm
mailto: fredrik.lindholm@ericsson.com
tel: +46 8 58531705
Value name: mikey
Long name: Multimedia Internet KEYing
Purpose: Usage of MIKEY with the key-mgmt attribute
Reference: Section 7 in RFC yyyy
Note that this registration will imply that the protocol identifier,
KMID, name space will be shared between SDP and RTSP.
Further values may be registered according to the "Specification
Required" policy as defined in [RFC2434]. Each new registration needs
to indicate the parameter name, and register it within IANA. Note
that the parameter name is case sensitive and it is recommended that
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the name should be in lower case letters. For each new registration,
it is mandatory that a permanent, stable, and publicly accessible
document exists that specifies the semantics of the registered
parameter and the requested details of interaction between the key
management protocol and SDP, as specified in RFC xxxx.
The registration itself of new values should be sent to IANA.
Registrations should include the following information:
* Contact: the contact name and email address
* Value name: the name of the value being registered (which MUST
comply with the KMID as defined in Section 2)
* Long Name: long-form name in English (optional)
* Purpose: short explanation of the purpose of the registered name.
* Reference: a reference to the specification (e.g. RFC number) of
the draft providing the usage guidelines in accordance to Section
4 (and also complying to the specified requirements).
7. Acknowledgments
Thanks to: Rolf Blom and Magnus Westerlund. A special thanks to Joerg
Ott and Colin Perkins.
8. Author's Addresses
Jari Arkko
Ericsson
02420 Jorvas Phone: +358 40 5079256
Finland Email: jari.arkko@ericsson.com
Elisabetta Carrara
Ericsson Research
SE-16480 Stockholm Phone: +46 8 50877040
Sweden EMail: elisabetta.carrara@ericsson.com
Fredrik Lindholm
Ericsson Research
SE-16480 Stockholm Phone: +46 8 58531705
Sweden EMail: fredrik.lindholm@ericsson.com
Mats Naslund
Ericsson Research
SE-16480 Stockholm Phone: +46 8 58533739
Sweden EMail: mats.naslund@ericsson.com
Karl Norrman
Ericsson Research
SE-16480 Stockholm Phone: +46 8 4044502
Sweden EMail: karl.norrman@ericsson.com
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9. References
9.1. Normative References
[OAM] Rosenberg, J. and Schulzrinne, H., "An Offer/Answer Model with
the Session Description Protocol (SDP)", IETF, RFC 3264.
[RTSP] Schulzrinne, H., Rao, A., and Lanphier, R., "Real Time
Streaming Protocol (RTSP)", IETF, RFC 2326.
[RFC2119] Bradner, S. "Key words for use in RFCs to Indicate
Requirement Levels", IETF, RFC 2119.
[SDPnew] Handley, M., Jacobson, V., and Perkins, C., "SDP: Session
Description Protocol", Internet Draft, IETF, Work in progress
(MMUSIC), draft-ietf-mmusic-sdp-new-13.txt.
[SIP] Handley, M., Schulzrinne, H., Schooler, E., and Rosenberg, J.,
"SIP: Session Initiation Protocol", IETF, RFC 3261.
[RFC2234] Crocker, D. and Overell, P., "Augmented BNF for Syntax
Specifications: ABNF", RFC 2234, November 1997.
[RFC2434] Narten, T. and Alvestrand, H., "Guidelines for Writing an
IANA Considerations Section in RFCs", IETF, RFC 2434.
[RFC3548] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", IETF, RFC 3548.
9.2. Informative References
[E2M] Ono, K. and Tachimoto, S., "End-to-middle security in the
Session Initiation Protocol (SIP)", Internet Draft, IETF, Work in
Progress.
[KERB] Kohl, J., Neuman, C., "The Kerberos Network Authentication
Service (V5)", IETF, RFC 1510.
[MIKEY] Arkko, J., Carrara, E., Lindholm, F., Naslund, M., and
Norrman, K., "MIKEY: Multimedia Internet KEYing", IETF, RFC yyyy,
[Internet Draft, Work in progress (MSEC)].
[SRTP] Baugher, M., Blom, R., Carrara, E., McGrew, D., Naslund, M,
Norrman, K., and Oran, D., "The Secure Real Time Transport Protocol",
Internet Draft, IETF, Work in Progress (AVT).
Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
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This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
This Internet-Draft expires in April 2004.
Arkko, et al. [Page 18]
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