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MSEC Working Group                                             S. Rowles
Internet-Draft                                             A. Yeung, Ed.
Intended status: Standards Track                                 P. Tran
Expires: September 2, 2010                                 Cisco Systems
                                                           March 1, 2010


                     Group Key Management for IKEv2
                         draft-yeung-g-ikev2-00

Abstract

   This document presents a new group key distribution protocol, using
   group key distribution RFC 3547 with IKEv2 RFC 4306.  The new
   protocol is similar to IKEv2 in message and payload formats as well
   as message semantics.  The protocol is in conformance with MSEC key
   management architecture that it contains two components: member
   registration and group rekeying, both downloading group security
   associations from the GCKS to a member of the group.

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on September 2, 2010.

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.




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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
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   the Trust Legal Provisions and are provided without warranty as
   described in the BSD License.


Table of Contents

   1.  Introduction and Overview  . . . . . . . . . . . . . . . . . .  5
     1.1.  Why do we need another GSA protocol? . . . . . . . . . . .  5
     1.2.  G-IKEv2 Payloads . . . . . . . . . . . . . . . . . . . . .  6

   2.  G-IKEv2 integration into IKEv2 protocol  . . . . . . . . . . .  7
     2.1.  UDP port . . . . . . . . . . . . . . . . . . . . . . . . .  7

   3.  G-IKEv2 Protocol . . . . . . . . . . . . . . . . . . . . . . .  8
     3.1.  G-IKEv2 member registration and secure channel
           establishment  . . . . . . . . . . . . . . . . . . . . . .  8
       3.1.1.  IKE_SA_INIT exchange . . . . . . . . . . . . . . . . .  8
       3.1.2.  GSA_AUTH exchange  . . . . . . . . . . . . . . . . . .  9
       3.1.3.  IKEv2 Header Initialization  . . . . . . . . . . . . . 10
       3.1.4.  GM Registration Operations . . . . . . . . . . . . . . 10
       3.1.5.  GCKS Registration Operations . . . . . . . . . . . . . 10
     3.2.  G-IKEv2 group maintenance channel  . . . . . . . . . . . . 11
       3.2.1.  G-IKEv2 REKEY exchange request . . . . . . . . . . . . 11
       3.2.2.  Forward and Backward Access Control  . . . . . . . . . 12
       3.2.3.  Forward Access Control Requirements  . . . . . . . . . 12
       3.2.4.  Deletion of SAs  . . . . . . . . . . . . . . . . . . . 13
       3.2.5.  GCKS Operations  . . . . . . . . . . . . . . . . . . . 14
       3.2.6.  GM Operations  . . . . . . . . . . . . . . . . . . . . 14

   4.  Header and Payload Formats . . . . . . . . . . . . . . . . . . 15
     4.1.  The G-IKEv2 Header . . . . . . . . . . . . . . . . . . . . 15
     4.2.  IDgroup Payload  . . . . . . . . . . . . . . . . . . . . . 15
     4.3.  Group Security Association Payload . . . . . . . . . . . . 15
       4.3.1.  Payloads following the GSA Payload . . . . . . . . . . 16
     4.4.  KEK Payload  . . . . . . . . . . . . . . . . . . . . . . . 17
       4.4.1.  KEK Attributes . . . . . . . . . . . . . . . . . . . . 18
       4.4.2.  KEK_MANAGEMENT_ALGORITHM . . . . . . . . . . . . . . . 18
       4.4.3.  KEK_ALGORITHM  . . . . . . . . . . . . . . . . . . . . 19
         4.4.3.1.  KEK_ALG_AES_CBC  . . . . . . . . . . . . . . . . . 19
         4.4.3.2.  KEK_ALG_AES_GCM  . . . . . . . . . . . . . . . . . 19
       4.4.4.  KEK_KEY_LENGTH . . . . . . . . . . . . . . . . . . . . 19



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       4.4.5.  KEK_KEY_LIFETIME . . . . . . . . . . . . . . . . . . . 20
       4.4.6.  SIG_HASH_ALGORITHM . . . . . . . . . . . . . . . . . . 20
       4.4.7.  SIG_ALGORITHM  . . . . . . . . . . . . . . . . . . . . 20
         4.4.7.1.  SIG_ALG_RSA  . . . . . . . . . . . . . . . . . . . 20
         4.4.7.2.  SIG_ALG_DSS  . . . . . . . . . . . . . . . . . . . 21
         4.4.7.3.  SIG_ALG_ECDSS  . . . . . . . . . . . . . . . . . . 21
       4.4.8.  SIG_KEY_LENGTH . . . . . . . . . . . . . . . . . . . . 21
     4.5.  GSA TEK Payload  . . . . . . . . . . . . . . . . . . . . . 21
       4.5.1.  TEK Protocol-Specific Payload  . . . . . . . . . . . . 22
     4.6.  GSA Group Associated Policy Payload  . . . . . . . . . . . 24
       4.6.1.  Activation Time Delay  . . . . . . . . . . . . . . . . 24
       4.6.2.  Deactivation_Time_Delay  . . . . . . . . . . . . . . . 25
       4.6.3.  Sender ID  . . . . . . . . . . . . . . . . . . . . . . 25
         4.6.3.1.  GCKS semantics . . . . . . . . . . . . . . . . . . 25
         4.6.3.2.  GM semantics . . . . . . . . . . . . . . . . . . . 26
     4.7.  Key Download Payload . . . . . . . . . . . . . . . . . . . 26
       4.7.1.  TEK Download Type  . . . . . . . . . . . . . . . . . . 28
         4.7.1.1.  TEK_ALGORITHM_KEY  . . . . . . . . . . . . . . . . 29
         4.7.1.2.  TEK_INTEGRITY_KEY  . . . . . . . . . . . . . . . . 29
         4.7.1.3.  TEK_SOURCE_AUTH_KEY  . . . . . . . . . . . . . . . 29
       4.7.2.  KEK Download Type  . . . . . . . . . . . . . . . . . . 29
         4.7.2.1.  KEK_ALGORITHM_KEY  . . . . . . . . . . . . . . . . 29
         4.7.2.2.  SIG_ALGORITHM_KEY  . . . . . . . . . . . . . . . . 30
       4.7.3.  LKH Download Type  . . . . . . . . . . . . . . . . . . 30
         4.7.3.1.  LKH_DOWNLOAD_ARRAY . . . . . . . . . . . . . . . . 30
         4.7.3.2.  LKH_UPDATE_ARRAY . . . . . . . . . . . . . . . . . 32
         4.7.3.3.  SIG_ALGORITHM_KEY  . . . . . . . . . . . . . . . . 33
     4.8.  Group Message Identification Payload . . . . . . . . . . . 34
     4.9.  Delete Payload . . . . . . . . . . . . . . . . . . . . . . 34
     4.10. Notify Payload . . . . . . . . . . . . . . . . . . . . . . 34
     4.11. Signature Payload  . . . . . . . . . . . . . . . . . . . . 35

   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 36
     5.1.  GSA registration and secure channel  . . . . . . . . . . . 36
     5.2.  GSA maintenance channel  . . . . . . . . . . . . . . . . . 36
       5.2.1.  Authentication/Authorization . . . . . . . . . . . . . 36
       5.2.2.  Confidentiality  . . . . . . . . . . . . . . . . . . . 36
       5.2.3.  Man-in-the-Middle Attack Protection  . . . . . . . . . 36
       5.2.4.  Replay/Reflection Attack Protection  . . . . . . . . . 36

   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 38
     6.1.  New registries . . . . . . . . . . . . . . . . . . . . . . 38
     6.2.  New payload and exchange types to existing IKEv2
           registry . . . . . . . . . . . . . . . . . . . . . . . . . 38
     6.3.  Payload Types  . . . . . . . . . . . . . . . . . . . . . . 38
     6.4.  New Name spaces  . . . . . . . . . . . . . . . . . . . . . 39

   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 40



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   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 41
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 41
     8.2.  Informative References . . . . . . . . . . . . . . . . . . 41

   Appendix A.  Differences between G-IKEv2 and RFC 3547  . . . . . . 43

   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 44












































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1.  Introduction and Overview

   This document presents a group key management protocol protected by
   IKEv2.  The group is protected by the security association derived in
   the mutual authentication between the group member and the group
   controller/key server (GCKS) using IKEv2 [RFC4306].  The GCKS
   downloads policy and keys after the GCKS authenticates the client.
   Though the initial payloads are unchanged,excepting an optional CERT
   Payload Request, the messages are referred to as GSA-INIT in this
   document for clarity.  The new payloads for G-IKEv2 are added in the
   GSA-AUTH exchange.  The result of the GSA-AUTH is that the GCKS
   downloads policy and keys for the group to the Group Members (GM).
   This document will reference the IKEv2 RFCs [4306 and 4718] but
   otherwise is intended to be a standalone document.  [RFC3547]
   presented GDOI using the ISAKMP domain of interpretation.  This
   document is updating the group security protocol to use IKEv2 without
   any need for a domain of interpretation, but will instead distinguish
   G-IKEv2 from IKEv2 by the port being used.  The message semantics of
   IKEv2 will be maintained in that all communications consist of pairs
   of messages.  The exception is in the case that when rekeys are
   issued in a multicast domain, the previous model [RFC3547] will be
   maintained: a multicast rekey sent by the GCKS will not expect a
   response from the GM.  A number of payloads were deemed unnecessary
   since [RFC3547].  These are described in Appendix A.

1.1.  Why do we need another GSA protocol?

   GDOI protocol specified in [RFC3547] is protected by IKEv1 phase1
   security association defined in [RFC2407], [RFC2408] and
   [RFC2409]2409; these documents are obsoleted and replaced by new
   version of IKE protocol defined in RFC 4306.  GSA provide group key
   management between member and key server using new IKEv2 protocol and
   inherit the following key advantages over GDOI:

   1.  Provide a simple mechanism for responder to keep minimal state
       and avoid DOS attack from forged IP address using cookie
       challenge exchange.

   2.  Improve performance and network latency by the reduced number of
       initial messages to complete the G-IKEv2 protocol from (9
       messages in main mode and quick mode, 6 messages in aggressive
       mode and quick) to 4 messages.

   3.  Fix cryptographic weakness with authentication HASH (ikev1
       authentication HASH specified in RFC-2409 does not include all
       ISAKMP payloads and does not include ISAKMP header).  This issue
       is document at [IKE-HASH]




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   4.  Improve protocol reliability where all unicast messages are
       ack'ed and sequenced.

   5.  Well defined behavior for error conditions to improve
       interoperability.

1.2.  G-IKEv2 Payloads

   1.  IDg (group ID) - The GM requests the GCKS for membership into the
       group by sending its IDg payload.

   2.  GMID (Group Message ID) - The current value of the IKEv2 header
       message ID that is communicated during the rekey message to the
       GM.

   3.  GSA (Group Security Association) - The GCKS sends the group
       policy to the GM using this payload.

   4.  GSA KEK (Group Security Association Key Encryption Key) - The KEK
       Payload MAY be sent as part of the group policy to ensure that
       the GCKS will send rekeys using the security credentials of the
       KEK.

   5.  GSA GAP (Group Associated Policy) - The GAP payload is providing
       the capability to send unique sender specific information to the
       group members as well as unique group policy specific to the
       group.  [Section 4.6].

   6.  GSA TEK (Group Security Association Traffic Encryption Key) - The
       GSA TEK Payload MAY be sent as part of the group policy to ensure
       that the GCKS will send the keying material for the group members
       to communicate securely amongst each other.

   7.  KD (Key Download) - The GCKS sends the control and data keys to
       the GM using the KD payload.

   8.  SIG (Signature Payload) The SIG payload provides a signed hash of
       the GCKS rekey message, which is verified by the GM.













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2.  G-IKEv2 integration into IKEv2 protocol

   The G-IKEv2 protocol provides the security mechanisms of IKEv2 (peer
   authentication, confidentiality, message_integrity) to protect the
   group negotiations required for G-IKEv2.  The G-IKEv2 exchange
   further provides group authorization, and secure policy and key
   download from the GCKS to its group members.

2.1.  UDP port

   G-IKEv2 SHOULD use port 848 since GDOI [RFC3547] and G-IKEv2 are
   related protocols where both provide group key manegement between
   group member and key server.  The version number in the IKEv2 header
   distinguishes the G-IKEv2 protocol from GDOI protocol [RFC3547].





































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3.  G-IKEv2 Protocol

3.1.  G-IKEv2 member registration and secure channel establishment

   The registration protocol consists of two exchanges, IKE_SA_INIT and
   GSA_AUTH.  Each exchange consists of request/response pairs.  The
   first exchange IKE_SA_INIT is defined in IKEv2 [RFC4306].  This
   exchange negotiates cryptographic algorithms, exchanges nonces and
   does Diffie-Hellman exchange between the member and the Group
   Controller Key Server (GCKS).

   The second exchange GSA_AUTH authenticates the previous messages,
   exchange identities and certificates, and downloads the data security
   keys (TEKs) and/or group key encrypting key (KEK) or KEK array.
   Parts of these messages are encrypted and integrity protected with
   keys established through the IKE_SA_INIT exchange, so the identities
   are hidden from eavesdroppers and all fields in all the messages are
   authenticated.  The GCKS MAY authorize group members to be allowed
   into the group as part of the GSA_AUTH exchange.  In the following
   descriptions, the payloads contained in the message are indicated by
   names as listed below.

        Notation      Payload
       ------------------------------------------------------------
        AUTH          Authentication
        CERT          Certificate
        CERTREQ       Certificate Request
        GMID          Group Message Identification
        GSA           Group Security Association
        HDR           IKEv2 Header
        IDg           Identification - Group
        IDi           Identification - Initiator
        IDr           Identification - Responder
        KE            Key Exchange
        Ni, Nr        Nonce SA Security Association

   The details of the contents of each payload are described in
   Section 4.  Payloads that may optionally appear will be shown in
   brackets, such as [CERTREQ], indicate that optionally a certificate
   request payload can be included.

3.1.1.  IKE_SA_INIT exchange









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       Member (Initiator)             GCKS (Responder)
      --------------------           ------------------
       HDR, SAi1, KEi, Ni    -->
                             <--      HDR, SAr1, KEr, Nr, [CERTREQ,]

   The group member initiates the IKE_SA_INIT exchange to the GCKS to
   negotiate cryptographic algorithms, exchange nonces, and perform a
   Diffie-Hellman exchange.

3.1.2.  GSA_AUTH exchange

   The security properties of the GSA_AUTH exchange are the same as the
   properties of the IKE_SA_AUTH exchange.  It is used to authenticate
   the GSA_INIT messages, exchange identities and certificates.  G-IKEv2
   also uses this exchange for group member registration and optionally
   authorization.

       Initiator (Member)                              Responder (GCKS)
      --------------------                            ------------------
       HDR, SK { IDi, [CERT,] [CERTREQ,] [IDr,] AUTH,
                 IDg }         -->

   After an unauthenticated secure channel is established by IKE_SA_INIT
   exchange, the member initiates a registration request to join a group
   indicated by IDg payload.

                                          <-- HDR, SK {IDr, [CERT,] AUTH,
                                                       [GMID,] GSA, KD}

   The GCKS MAY inform the group member the current value of the rekey
   message_id using the GMID payload.  The first GSA_REKEY request's
   message id the member receives MUST be greater than GMID value.  The
   GMID payload MUST be present if the GSA payload contains an GSA KEK
   attribute, indicating that the GCKS will be sending rekeys.

   The GCKS also informs the member of the cryptographic policies of the
   group in the GSA payload, which describes the KEK and/or TEK keying
   material and/or the policy in the GAP, and authentication transforms.
   The SPIs for the data traffic are also determined by the GCKS and
   downloaded in the GSA payload.  The GSA KEK attribute contains the
   G-IKEv2 SPI for the Re-key SA, which is not negotiated but
   downloaded.  The GSA TEK attribute contains a SPI as defined in
   Section 4.5.1 of this document.  If a Re-key SA is defined in the SA
   payload, indicated by the presence of the GSA KEK attribute, then the
   KD will contain the SA KEK; if one or more Data-security SAs are
   defined in the GSA payload, the KD will contain the TEKs.  The GAP
   payload MAY specify the sender specific information if any of the AES
   counter-based modes are being used to provide unique sender



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   information to the GMs.  The GAP payload may also provide the ATD or
   DTD providing specifying activation and deactivation delays for SAs
   generated from the TEKs.

   G-IKEv2 member registration MAY have a few more messages exchange if
   the EAP method, cookie challenge (for DoS) and invalid KE are used.

   In addition to the IKEv2 error handling, GCKS can reject the
   registration request when IDg is invalid or authorization fail, etc.
   In these cases, see Section 4.10, the GSA_AUTH response will include
   notify indicate errors.  The member SHOULD send an IKEv2 delete using
   the INFORMATIONAL message exchange to bring down the authenticated
   IKE SA.

3.1.3.  IKEv2 Header Initialization

   The Major Version is (2) and Minor Version number (0) according to
   IKEv2 [RFC4306], and maintained in this document.  The G-IKEv2 GSA-
   INIT uses the SPI according to IKEv2 [RFC4306],section 2.6.

3.1.4.  GM Registration Operations

   A G-IKEv2 Initiator (GM) requesting registration contacts the GCKS
   using the IKE_SA_INIT exchange and receives the response from the
   GCKS.  This exchange is unchanged from the IKEv2 protocol.  Upon
   completion of parsing and verifying the IKE_SA_INIT response, it
   sends the GSA_AUTH message with the IKEv2 payloads from IKE_SA_AUTH
   along with the Group ID informing the GCKS of the group the initiator
   wishes to join.  The initiator then parses the response from the GCKS
   authenticating the exchange using the IKEv2 payloads, then accessing
   the GMID, GSA, and KD.  The GMID is optionally accessed if rekey is
   desired in the system, where GMID provides the current message ID of
   the most recent rekey message.  The GSA is parsed providing the TEK
   and/or KEK and/or the GAP policy.  Finally the KD is parsed providing
   the keying material for the TEK and/or KEK.

3.1.5.  GCKS Registration Operations

   A G-IKEv2 GCKS receives the IKE_SA_INIT message and responds with the
   IKE_SA_INIT response unchanged from IKEv2.  Upon receiving the
   GSA_AUTH message, and after authenticating the peer, the GCKS locates
   the group the initiator wishes to join, extracts the policy for that
   group, and generates the policy in the GSA payload, along with the
   keying material in the KD payload.  Optionally, the GAP payload may
   provide SSID information if the AES counter modes are being used as
   the transforms to provide unique sender information to the GMs, as
   well as ATD or DTD if it is desired to address the activation and
   deactivation time delays of the TEK SA.  If the GCKS desires



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   authorization, the GCKS authorizes the peer against the specified
   credentials before sending the GSA_AUTH response.  The support for
   the G-IKEv2 group maintenance channel is optional, the GMID SHOULD be
   sent if it is supported.

3.2.  G-IKEv2 group maintenance channel

   The GCKS MAY send the GSA Rekey if the KEK attribute is present in
   the G-IKEv2 registration.  Though the G-IKEv2 Rekey is optional, it
   plays a crucial role for large and dynamic groups.  The GCKS is
   responsible for rekeying of the secure group per the group policy.
   The GCKS uses multicast to transport the rekey message.  The G-IKEv2
   protocol uses GSA_REKEY exchange type in G-IKEv2 header identifying
   it as a rekey message.  This rekey message is protected by the
   registration exchanges.

3.2.1.  G-IKEv2 REKEY exchange request

   The GCKS initiates the G-IKEv2 Rekey securely using IP multicast.
   The GCKS Rekey message replaces the Rekey GSA KEK or KEK array,
   and/or creates a new Data-Security SA TEK.  The SA SSA SHOULD NOT be
   part of the Rekey Exchange as this is sender specific information and
   the Rekey Exchange is group specific.  The GCKS initiates the
   GSA_REKEY exchange as following:

       Members (Responder)            GCKS (Initiator)
      --------------------           ------------------
                              <--     HDR, SK { GSA, KD, SIG }

   HDR is defined in Section 4.1.  The GSA payload contains the current
   rekey and data security SA payloads.  The GSA may contain a new data
   security SA and/or a new rekey SA, which, optionally contains an LKH
   rekey SA, Section 4.3.

   The KD represents the keys for the policy sent in the GSA.  If the
   data security SA is being refreshed in this rekey message, the IPSec
   keys are updated in the KD, and/or if the rekey SA is being refreshed
   in this rekey message, the rekey Key or the LKH KEK array is updated
   in the KD payload.

   The SIG payload is a signature of the hash of the message, not
   including the G-IKEv2 header, to ensure the integrity of the rekey
   message.

   After adding the Signature of the above Hash to the rekey message,
   the current KEK encryption key encrypts all the payloads following
   the HDR.




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3.2.2.  Forward and Backward Access Control

   Through G-IKEv2 rekey, the G-IKEv2 supports algorithms such as LKH
   that have the property of denying access to a new group key by a
   member removed from the group (forward access control) and to an old
   group key by a member added to the group (backward access control).
   An unrelated notion to PFS, "forward access control" and "backward
   access control" have been called "perfect forward security" and
   "perfect backward security" in the literature [RFC2627].

   Group management algorithms providing forward and backward access
   control other than LKH have been proposed in the literature,
   including OFT [OFT] and Subset Difference [NNL].  These algorithms
   could be used with G-IKEv2, but are not specified as a part of this
   document.

   Support for group management algorithms is supported via the
   KEY_MANAGEMENT_ALGORITHM attribute which is sent in the SA_KEK
   payload.  G-IKEv2 specifies one method by which LKH can be used for
   forward and backward access control.  Other methods of using LKH, as
   well as other group management algorithms such as OFT or Subset
   Difference may be added to G-IKEv2 as part of a later document.  Any
   such addition MUST be due to a Standards Action as defined in
   [RFC2434].

3.2.3.  Forward Access Control Requirements

   When group membership is altered using a group management algorithm
   new SA_TEKs (and their associated keys) are usually also needed.  New
   SAs and keys ensure that members who were denied access can no longer
   participate in the group.

   If forward access control is a desired property of the group, new
   SA_TEKs and the associated key packets in the KD payload MUST NOT be
   included in a G-IKEv2 rekey message which changes group membership.
   This is required because the SA_TEK policy and the associated key
   packets in the KD payload are not protected with the new KEK.  A
   second G-IKEv2 rekey message can deliver the new SA_TEKS and their
   associated keys because it will be protected with the new KEK, and
   thus will not be visible to the members who were denied access.

   If forward access control policy for the group includes keeping group
   policy changes from members that are denied access to the group, then
   two sequential G-IKEv2 rekey messages changing the group KEK MUST be
   sent by the GCKS.  The first G-IKEv2 rekey message creates a new KEK
   for the group.  Group members, which are denied access, will not be
   able to access the new KEK, but will see the group policy since the
   G-IKEv2 rekey message is protected under the current KEK.  A



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   subsequent G-IKEv2 rekey message containing the changed group policy
   and again changing the KEK allows complete forward access control.  A
   G-IKEv2 rekey message MUST NOT change the policy without creating a
   new KEK.

   If other methods of using LKH or other group management algorithms
   are added to G-IKEv2, those methods MAY remove the above restrictions
   requiring multiple G-IKEv2 rekey messages, providing those methods
   specify how forward access control policy is maintained within a
   single G-IKEv2 rekey message.

3.2.4.  Deletion of SAs

   There are occasions the GCKS may want to signal to receivers to
   delete policy at the end of a broadcast, or if group policy has
   changed.  Deletion of keys MAY be accomplished by sending the G-IKEv2
   Delete Payload [RFC4306], section 3.11 as part of the G-IKEv2 Rekey
   Exchange.

   One or more Delete payloads MAY be placed following the HDR payload
   in the G-IKEv2 Rekey Exchange.  The Protocol-ID field contains TEK
   protocol id values, defined in section 4.6 of this document.  In
   order to delete a KEK SA, the value of zero MUST be used as the
   protocol id.  Note that only one protocol id value can be defined in
   a Delete payload.  If a TEK and a KEK SA must be deleted, they must
   be sent in different Delete payloads.  Similarly, if an TEK
   specifying ESP and a TEK specifying AH need to be deleted, they must
   be sent in different Delete payloads.

   When a policy delete is required the GCKS sends a rekey of the
   following format:

       Members (Responder)            GCKS (Initiator)
      --------------------           ------------------
                              <--     HDR, SK { DEL, [GSA], [KD], SIG }

   The GSA MAY specify the remaining active time of the remaining policy
   by using the DTD attribute in the GAP Payload.  If a GCKS has no
   further SAs to send to group members, the SA and KD payloads MUST be
   omitted from the message.  There may be circumstances where the GCKS
   may want to start over with a clean slate.  If the administrator is
   no longer confident in the integrity of the group, the GCKS can
   signal deletion of all policy of a particular TEK protocol by sending
   a TEK with a SPI value equal to zero in the delete payload.  For
   example, if the GCKS wihses to remove all the KEKs and all the TEKs
   in the group, the GCKS SHOULD send a delete payload with a spi of
   zero and a protocol_id of a TEK protocol_id value define in
   Section 4.5, followed by another delete paylad with a spi of zero and



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   and protocol_id of zero, indicating that the KEK SA should be
   deleted.

3.2.5.  GCKS Operations

   The GCKS may initiate a rekey message if group membership and/or
   policy has changed, or if the keys are about to expire.  The GCKS
   builds an IKEv2 HDR with a message_id with a value that is one
   greater than the previous rekey.  The GSA and KD follow with the same
   characteristics as in the GSA_Registration exchange.  The SIG payload
   is created by hashing the string "G-IKEv2" and the message created so
   far, and then digitally signed.  Finally, the payloads following the
   HDR are encrypted using the current KEK encryption key.

3.2.6.  GM Operations

   The group member receives the Rekey Message from the GCKS, decrypts
   the message using the current KEK, validates the signature, verifies
   the message_id is one or more greater than that of the last rekey SA
   received, and processes the GSA and KD payloads.  The group member
   then downloads the new data security SA and/or new Rekey SA.  The
   parsing of the payloads is similar to the registration exchange.





























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4.  Header and Payload Formats

   Refer to IKEv2 [RFC4306] for existing payloads.

4.1.  The G-IKEv2 Header

   G-IKEv2 uses the same IKE header format as specified in RFC 4306
   section 3.1.

   Several new payload formats are required in the group security
   exchanges.

              Next Payload Type                   Value
              -----------------                   -----
              Group Identification (IDg)           TBD
              Group Security Association (GSA)     TBD
              Group Message ID (GMID)              TBD
              GSA KEK Payload (GSAK)               TBD
              GSA GAP Payload (GGAP)               TBD
              GSA TEK Payload (GSAT)               TBD
              Key Download (KD)                    TBD
              Signature Payload (SIG)              TBD

   New exchange types GSA_AUTH and GSA_REKEY are added to the IKEv2
   [RFC4306] protocol.

              Exchange Type           Value
              --------------          -----
              GSA_AUTH                 TBD
              GSA_REKEY                TBD

   Major Version is 2 and Minor Version is 0 as in IKEv2 [RFC4306].  IKE
   SA initiator SPI, IKE SA responder SPI, Flags, Message Id are as
   specified in [RFC4306].

4.2.  IDgroup Payload

   The IDg Payload allows the group member to indicate which group it
   wants to join.  The payload is constructed by using the IKEv2
   [RFC4306] Identification Payload.

4.3.  Group Security Association Payload

   The Group Security Association payload is used by the GCKS to assert
   security attributes for both Re-key and Data-security SAs.






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       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
      ! Next Payload  !   RESERVED    !         Payload Length        !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      ! GSA Attribute Next Payload    !          RESERVED2            !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!

   The Security Association Payload fields are defined as follows:

   o  Next Payload (1 octet) -- Identifies the next payload for the
      G-IKEv2 registrationG-IKEv2 registration or the G-IKEv2 rekey
      message as defined above.  The next payload MUST NOT be a GSAK
      Payload or GSAT Payload type, but the next non-Security
      Association type payload.

   o  RESERVED (1 octet) -- Must be zero.

   o  Payload Length (2 octets) -- Is the octet length of the current
      payload including the generic header and all TEK and KEK payloads.

   o  GSA Attribute Next Payload (1 octet) -- Must be either a GSAK
      Payload or a GSAT Payload or GAP payload.  See section 5.2.1 for a
      description of which circumstances are required for each payload
      type to be present.

   o  RESERVED2 (2 octets) -- Must be zero.

4.3.1.  Payloads following the GSA Payload

   Payloads that define specific security association attributes for the
   KEK and/or TEKs used by the group MUST follow the GSA payload.  How
   many of each payload is dependent upon the group policy.  There may
   be zero or one GSA KEK Payloads, and zero or more GSA TEK Payloads,
   where either one GSA KEK or GSA TEK payload MUST be present.

   This latitude allows various group policies to be accommodated.  For
   example if the group policy does not require the use of a Re-key SA,
   the GCKS would not need to send an GSA KEK attribute to the group
   member since all SA updates would be performed using the Registration
   SA.  Alternatively, group policy might use a Re-key SA but choose to
   download a KEK to the group member only as part of the Registration
   SA.  Therefore, the KEK policy (in the GSA KEK attribute) would not
   be necessary as part of the Re-key SA message GSA payload.

   Specifying multiple GSA TEKs allows multiple sessions to be part of
   the same group and multiple streams to be associated with a session
   (e.g., video, audio, and text) but each with individual security



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   association policy.

4.4.  KEK Payload

   The GSA KEK (GSAK) payload contains security attributes for the KEK
   method for a group and parameters specific to the G-IKEv2
   registration operation.  The source and destination identities
   describe the identities used for the G-IKEv2 registration datagram.

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
      ! Next Payload  !   RESERVED    !         Payload Length        !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
      !                                                               !
      ~                              SPI                              ~
      !                                                               !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
      !                                                               !
      ~                 <Source Traffic Selector>                     ~
      !                                                               !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
      !                                                               !
      ~               <Destination Traffic Selector>                  ~
      !                                                               !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
      ~                        KEK Attributes                         ~
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!

   The GSAK Payload fields are defined as follows:

   o  Next Payload (1 octet) -- Identifies the next payload for the
      G-IKEv2 registration or the G-IKEv2 rekey message.  The only valid
      next payload types for this message are a GSA TEK Payload or zero
      to indicate there is no GSA TEK payload.

   o  RESERVED (1 octet) -- Must be zero.

   o  Payload Length (2 octets) -- Length of this payload, including the
      KEK attributes.

   o  SPI (16 octets) -- Security Parameter Index for the KEK.  The SPI
      must be the IKEv2 Header SPI pair where the first 8 octets become
      the "Initiator's SPI" field of the G-IKEv2 rekey message IKEv2
      HDR, and the second 8 octets become the "Responder's SPI" in the
      same HDR.  As described above, these cookies are assigned by the
      GCKS.




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   o  Source & Destination Traffic Selector - Substructures describing
      the source and destination of the identities.  Defined format and
      values are specified by IKEv2 [RFC4306], section 3.13.1.

   o  KEK Attributes -- Contains KEK policy attributes associated with
      the group.  The following sections describe the possible
      attributes.  Any or all attributes may be optional, depending on
      the group policy.

4.4.1.  KEK Attributes

   The following attributes may be present in a GSA KEK Payload.  The
   attributes must follow the format defined in IKEv2 [RFC4306] section
   3.3.5.  In the table, attributes that are defined as TV are marked as
   Basic (B); attributes that are defined as TLV are marked as Variable
   (V).

                ID Class                   Value    Type
                --------                   -----    ----
                RESERVED                     0
                KEK_MANAGEMENT_ALGORITHM     1        B
                KEK_ALGORITHM                2        B
                KEK_KEY_LENGTH               3        B
                KEK_KEY_LIFETIME             4        V
                SIG_HASH_ALGORITHM           5        B
                SIG_ALGORITHM                6        B
                SIG_KEY_LENGTH               7        B

   The following attributes may only be included in a G-IKEv2
   registration message: KEK_MANAGEMENT_ALGORITHM.

   Minimum attributes that must be sent as part of an GSA KEK:
   KEK_ALGORITHM, KEK_KEY_LENGTH (if the cipher definition includes a
   variable length key), KEK_KEY_LIFETIME, SIG_HASH_ALGORITHM (except
   for DSA based algorithms), SIG_ALGORITHM, and SIG_KEY_LENGTH.

4.4.2.  KEK_MANAGEMENT_ALGORITHM

   The KEK_MANAGEMENT_ALGORITHM class specifies the group KEK management
   algorithm used to provide forward or backward access control (i.e.,
   used to exclude group members).  Defined values are specified in the
   following table.









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                  KEK Management Type               Value
                  -------------------               -----
                  RESERVED                            0
                  LKH                                 1
                  Standards Action                   2-127
                  Private Use                       128-255

4.4.3.  KEK_ALGORITHM

   The KEK_ALGORITHM class specifies the encryption algorithm using with
   the KEK.  Defined values are specified in the following table.

                   Algorithm Type      Value
                   --------------      -----
                   RESERVED              0
                   KEK_ALG_AES_CBC       1
                   KEK_ALG_AES_GCM       2
                   Standards Action     3-127
                   Private Use        128-255

   If a KEK_MANAGEMENT_ALGORITHM is defined which defines multiple keys
   (e.g., LKH), and if the management algorithm does not specify the
   algorithm for those keys, then the algorithm defined by the
   KEK_ALGORITHM attribute MUST be used for all keys which are included
   as part of the management.

4.4.3.1.  KEK_ALG_AES_CBC

   This algorithm specifies AES as described in [FIPS197].  The mode of
   operation for AES is Cipher Block Chaining (CBC) as recommended in
   [SP800-38A].

4.4.3.2.  KEK_ALG_AES_GCM

   This algorithm specifies AES as described in [FIPS197].  The mode of
   operation for AES is Galois/Counter Mode (GCM) as recommended in
   [SP800-38D].

4.4.4.  KEK_KEY_LENGTH

   The KEK_KEY_LENGTH class specifies the KEK Algorithm key length (in
   bits).

   The Group Controller/Key Server (GCKS) adds the KEK_KEY_LEN attribute
   to the GSA payload when distributing KEK policy to group members.
   The group member verifies whether or not it has the capability of
   using a cipher key of that size.  If the cipher definition includes a
   fixed key length, the group member can make its decision solely using



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   KEK_ALGORITHM attribute and does not need the KEK_KEY_LEN attribute.
   Sending the KEK_KEY_LEN attribute in the GSA payload is OPTIONAL if
   the KEK cipher has a fixed key length.

4.4.5.  KEK_KEY_LIFETIME

   The KEK_KEY_LIFETIME class specifies the maximum time for which the
   KEK is valid.  The GCKS may refresh the KEK at any time before the
   end of the valid period.  The value is a four (4) octet number
   defining a valid time period in seconds.

4.4.6.  SIG_HASH_ALGORITHM

   SIG_HASH_ALGORITHM specifies the SIG payload hash algorithm.  The
   following tables define the algorithms for SIG_HASH_ALGORITHM.

                   Algorithm Type       Value
                   --------------       -----
                   RESERVED               0
                   SIG_HASH_SHA256        1
                   Standards Action      2-127
                   Private Use         128-255

4.4.7.  SIG_ALGORITHM

   The SIG_ALGORITHM class specifies the SIG payload signature
   algorithm.  Defined values are specified in the following table.


                   Algorithm Type        Value
                   --------------        -----
                   RESERVED                0
                   SIG_ALG_RSA             1
                   SIG_ALG_DSS             2
                   SIG_ALG_ECDSS           3
                   Standards Action       4-127
                   Private Use          128-255

   A G-IKEv2 implementation MUST support the following algorithm
   attribute: SIG_ALG_RSA.

4.4.7.1.  SIG_ALG_RSA

   This algorithm specifies the RSA digital signature algorithm as
   described in [RSA].






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4.4.7.2.  SIG_ALG_DSS

   This algorithm specifies the DSS digital signature algorithm as
   described in [FIPS186-2].

4.4.7.3.  SIG_ALG_ECDSS

   This algorithm specifies the Elliptic Curve digital signature
   algorithm as described in [FIPS186-2].

4.4.8.  SIG_KEY_LENGTH

   The SIG_KEY_LENGTH value MUST be a number representing the length of
   the KEK encryption key in bits.

4.5.  GSA TEK Payload

   The GSA TEK (GSAT) payload contains security attributes for a single
   TEK associated with a group.

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
      ! Next Payload  !   RESERVED    !         Payload Length        !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
      ! Protocol-ID   !       TEK Protocol-Specific Payload           ~
      +-+-+-+-+-+-+-+-+                                               ~
      ~                                                               ~
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!

   The GSAT Payload fields are defined as follows:

   o  Next Payload (1 octet) -- Identifies the next payload for the
      G-IKEv2 registration or the G-IKEv2 rekey message.  The only valid
      next payload types for this message are another GSAT Payload or
      zero to indicate there are no more security association
      attributes.

   o  RESERVED (1 octet) -- Must be zero.

   o  Payload Length (2 octets) -- Length of this payload, including the
      TEK Protocol-Specific Payload.

   o  Protocol-ID (1 octet) -- Value specifying the Security Protocol.
      The following table defines values for the Security Protocol






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             Protocol ID                       Value
             -----------                       -----
             RESERVED                            0
             GSA_PROTO_IPSEC_ESP                 1
             GSA_PROTO_IPSEC_AH                  2
             Standards Action                   3-127
             Private Use                      128-255

   Support for the GSA_PROTO_IPSEC_AH GSA TEK is OPTIONAL.

   o  TEK Protocol-Specific Payload (variable) -- Payload which
      describes the attributes specific for the Protocol-ID.

4.5.1.  TEK Protocol-Specific Payload

   The TEK Protocol-Specific payload contains of two traffic selectors
   for source and destination of the protecting traffic, SPI, Transform,
   and GSA Life Attributes.

   The TEK Protocol-Specific payload for ESP is as follows:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !                             SPI                               !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
      |                                                               |
      ~                 <Source Traffic Selector>                     ~
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      ~               <Destination Traffic Selector>                  |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
      |                                                               |
      ~                         <Transform>                           ~
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
      !                        SA Attributes                          ~
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!

   The GSAT Payload fields are defined as follows:

   o  SPI (4 octets) -- Security Parameter Index.

   o  Source & Destination Traffic Selectors - The traffic selectors
      describe the source and the destination of the protecting traffic.
      The format and values are defined in IKEv2 [RFC4306], section



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      3.13.1.

   o  Transform -- A substructure specifies the transform information.
      The format and values are defined in IKEv2 [RFC4306], section
      3.3.2.

   o  GSA Life Attributes -- The GSA Life Attributes are defined as
      below.  The attributes must follow the format defined in IKEv2
      [RFC4306], section 3.3.5.

   Attribute Types

             class               value           type
       -------------------------------------------------
       GSA Life Type                1               B
       GSA Life Duration            2               V

       Class Values

         GSA Life Type
         GSA Duration

           Specifies the time-to-live for the overall security
           association.  When the GSA expires, all keys negotiated under
           the association (AH or ESP) must be renegotiated.  The life
           type values are:

           RESERVED                0
           seconds                 1
           kilobytes               2

           Values 3-61439 are reserved to IANA.  Values 61440-65535 are
           for private use.  For a given Life Type, the value of the
           Life Duration attribute defines the actual length of the
           component lifetime -- either a number of seconds, or a number
           of Kbytes that can be protected.

           If unspecified, the default value shall be assumed to be
           28800 seconds (8 hours).

           An GSA Life Duration attribute MUST always follow an GSA Life
           Type which describes the units of duration.









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4.6.  GSA Group Associated Policy Payload

   [RFC3547] provides for the distribution of policy in the G-IKEv2
   registration exchange in an SA payload.  Policy can define G-IKEv2
   rekey policy (GSA KEK) or traffic encryption policy (GSA TEK) such as
   IPsec policy.  There is a need to distribute group policy that fits
   into neither category.  Some of this policy is generic to the group,
   and some is sender-specific policy for a particular group member.

   G-IKEv2 distributes this associated group policy in a new payload
   called the GSA Group Associated Policy (GSA SAP).  The GSA GAP
   payload follows any GSA KEK payload, and is placed before any GSA TEK
   payloads.  In the case that group policy does not include an GSA KEK,
   the GSA Attribute Next Payload field in the GSA payload MAY indicate
   the GSA GAP payload.

   The GSA GAP payload is defined as follows:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
      ! Next Payload  !   RESERVED    !        Payload Length         !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
      !               Group Associated Policy Attributes              ~
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!

   The GSA GAP payload fields are defined as follows:

   o  Next Payload (1 octet) -- Identifies the next payload present in
      the G-IKEv2 registration or the G-IKEv2 rekey message.  The only
      valid next payload type for this message is an GSA TEK or zero to
      indicate there are no more security association attributes.

   o  RESERVED (1 octet) -- Must be zero.

   o  Payload Length (2 octets) -- Length of this payload, including the
      GSA GAP header and Attributes.

   o  Group Associated Policy Attributes (variable) -- Contains
      attributes following the format defined in Section 3.3.5 of
      [RFC4306].

   Several group associated policy attributes are defined below.

4.6.1.  Activation Time Delay

   The Activation Time Delay (ATD) attribute allows the GCKS to specify
   how long a after the start of a re-key event that a group member is



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   to activate new TEKs.  If a group member receives a TEK with an ATD
   value, but discovers that it has no current SAs matching the policy
   in the TEK, then it SHOULD create and install SAs from the TEK
   immediately.

4.6.2.  Deactivation_Time_Delay

   The Deactivation Time Delay (DTD) attribute allows the GCKS to
   specify how long a after the start of a re-key event that a group
   member is to deactivate existing TEKs.  The value is in seconds.

4.6.3.  Sender ID

   Several new AES counter-based modes of operation have been specified
   for ESP [RFC3686], [RFC4106], [RFC4309], [RFC4543] and AH [RFC4543].
   These AES counter-based modes require that no two senders in the
   group ever send a packet with the same IV.  This requirement can be
   met using the method described in [I-D.ietf-msec-ipsec-group-counter-
   modes], which requires each sender to be allocated a unique Sender ID
   (SID).

   The SENDER_ID attribute is used to distribute a SID to a group member
   during the GSA_AUTH exchange messages.  Other algorithms with the
   same need may be defined in the future; the sender MUST use the IV
   construction method described above with those algorithms as well.

   The SENDER_ID attribute value contains the following fields.

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
      !   SID Length  !                    SID Value                  ~
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!

   o  SID Length (1 octet) -- A natural number defining the number of
      bits to be used in the SID field of the counter mode transform
      nonce.

   o  SID Value (variable) -- The Sender ID value allocated to the group
      member.

4.6.3.1.  GCKS semantics

   The GCKS maintains a SID counter (SIDC).  It is incremented each time
   a SENDER_ID attribute is distributed to a group member.  The first
   group member to register is given the SID of 1.

   Any group member registering will be given a new SID value, which



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   allows group members to act as a group sender when an older SID value
   becomes unusable (as described in the next section).

   A GCKS MAY allocate multiple SID values in one SA SSA payload.
   Allocating several SID values at the same time to a group member
   expected to send at a high rate would obviate the need for the group
   member to re-register as frequently.

   If a GCKS allocates all SID values, it can no longer respond to
   G-IKEv2 registrations and must re-initialize the entire group.  This
   is done by issuing DELETE notifications for all ESP and AH SAs in a
   G-IKEv2 rekey message, resetting the SIDC to zero, and creating new
   ESP and AH SAs that match the group policy.

   When group members re-register, the SIDs are allocated again
   beginning with the value 1 as described above.  Each re-registering
   group member will be given a new SID and the new group policy.

   The SENDER_ID attribute MUST NOT be sent as part of a GSA_REKEY
   exchange message, because distributing the same sender-specific
   policy to more than one group member may reduce the security of the
   group.

4.6.3.2.  GM semantics

   The SENDER_ID attribute value distributed to the group member MUST be
   used by that group member as the Sender Identifier (SID) field
   portion of the IV.  The SID is used for all counter mode SAs
   distributed by the GCKS to be used for communications sent as a part
   of this group.  When the Sender-Specific IV (SSIV) field for any
   IPsec SA is exhausted, the group member MUST no longer act as a
   sender using its active SID.  The group member SHOULD re-register,
   during which time the GCKS will issue a new SID to the group member.
   The new SID replaces the existing SID used by this group member, and
   also resets the SSIV value to it's starting value.  A group member
   MAY re-register prior to the actual exhaustion of the SSIV field to
   avoid dropping data packets due to the exhaustion of available SSIV
   values combined with a particular SID value.

   A group member MUST NOT process SENDER_ID attribute present in a
   GSA_REKEY exchange message.

4.7.  Key Download Payload

   The Key Download Payload contains group keys for the group specified
   in the SA Payload.  These key download payloads can have several
   security attributes applied to them based upon the security policy of
   the group as defined by the associated SA Payload.



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        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
       ! Next Payload  !   RESERVED    !         Payload Length        !
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
       ! Number of Key Packets         !            RESERVED2          !
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
       ~                    Key Packets                                ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!

   The Key Download Payload fields are defined as follows:

   o  Next Payload (1 octet) -- Identifier for the payload type of the
      next payload in the message.  If the current payload is the last
      in the message, then this field will be zero.

   o  RESERVED (1 octet) -- Unused, set to zero.

   o  Payload Length (2 octets) -- Length in octets of the current
      payload, including the generic payload header.

   o  Number of Key Packets (2 octets) -- Contains the total number of
      both TEK and Rekey arrays being passed in this data block.

   o  Key Packets Several types of key packets are defined.  Each Key
      Packet has the following format.

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
      !   KD Type     !   RESERVED    !            KD Length          !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
      !    SPI Size   !                   SPI (variable)              ~
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
      ~                    Key Packet Attributes                      ~
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!

   o  Key Download (KD) Type (1 octet) -- Identifier for the Key Data
      field of this Key Packet.












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                          Key Download Type        Value
                          -----------------        -----
                          RESERVED                   0
                          TEK                        1
                          KEK                        2
                          LKH                        3
                          Standards Action          4-127
                          Private Use             128-255

   "KEK" is a single key whereas LKH is an array of key-encrypting keys.

   o  RESERVED (1 octet) -- Unused, set to zero.

   o  Key Download Length (2 octets) -- Length in octets of the Key
      Packet data, including the Key Packet header.

   o  SPI Size (1 octet) -- Value specifying the length in octets of the
      SPI as defined by the Protocol-Id.

   o  SPI (variable length) -- Security Parameter Index which matches a
      SPI previously sent in an GSAK or GSAT Payload.

   o  Key Packet Attributes (variable length) -- Contains Key
      information.  The format of this field is specific to the value of
      the KD Type field.  The following sections describe the format of
      each KD Type.

4.7.1.  TEK Download Type

   The following attributes may be present in a TEK Download Type.
   Exactly one attribute matching each type sent in the GSAT payload
   MUST be present.  The attributes must follow the format defined in
   IKEv2 (Section 3.3.5 of [RFC4306]).  In the table, attributes defined
   as TV are marked as Basic (B); attributes defined as TLV are marked
   as Variable (V).

                TEK Class                 Value      Type
                ---------                 -----      ----
                RESERVED                     0
                TEK_ALGORITHM_KEY            1        V
                TEK_INTEGRITY_KEY            2        V
                TEK_SOURCE_AUTH_KEY          3        V

   If no TEK key packets are included in a Registration KD payload, the
   group member can expect to receive the TEK as part of a Re-key SA.
   At least one TEK must be included in each Re-key KD payload.
   Multiple TEKs may be included if multiple streams associated with the
   SA are to be rekeyed.



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4.7.1.1.  TEK_ALGORITHM_KEY

   The TEK_ALGORITHM_KEY class declares that the encryption key for this
   SPI is contained as the Key Packet Attribute.  The encryption
   algorithm that will use this key was specified in the GSAT payload.

   In the case that the algorithm requires multiple keys, all keys will
   be included in one attribute.

4.7.1.2.  TEK_INTEGRITY_KEY

   The TEK_INTEGRITY_KEY class declares that the integrity key for this
   SPI is contained as the Key Packet Attribute.  The integrity
   algorithm that will use this key was specified in the GSAT payload.
   Thus, G-IKEv2 assumes that both the symmetric encryption and
   integrity keys are pushed to the mebmber.  SHA256 keys will consist
   of 256 bits.

4.7.1.3.  TEK_SOURCE_AUTH_KEY

   The TEK_SOURCE_AUTH_KEY class declares that the source authentication
   key for this SPI is contained in the Key Packet Attribute.  The
   source authentication algorithm that will use this key was specified
   in the GSAT payload.

4.7.2.  KEK Download Type

   The following attributes may be present in a KEK Download Type.
   Exactly one attribute matching each type sent in the GSAK payload
   MUST be present.  The attributes must follow the format defined in
   IKEv2 (Section 3.3.5 of [RFC4306]).  In the table, attributes defined
   as TV are marked as Basic (B); attributes defined as TLV are marked
   as Variable (V).

                KEK Class                 Value      Type
                ---------                 -----      ----
                RESERVED                     0
                KEK_ALGORITHM_KEY            1        V
                SIG_ALGORITHM_KEY            2        V

   If the KEK key packet is included, there MUST be only one present in
   the KD payload.

4.7.2.1.  KEK_ALGORITHM_KEY

   The KEK_ALGORITHM_KEY class declares the encryption key for this SPI
   is contained in the Key Packet Attribute.  The encryption algorithm
   that will use this key was specified in the GSAK payload.



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   If the mode of operation for the algorithm requires an Initialization
   Vector (IV), an explicit IV MUST be included in the KEK_ALGORITHM_KEY
   before the actual key.

4.7.2.2.  SIG_ALGORITHM_KEY

   The SIG_ALGORITHM_KEY class declares that the public key for this SPI
   is contained in the Key Packet Attribute, which may be useful when no
   public key infrastructure is available.  The signature algorithm that
   will use this key was specified in the GSAK payload.

4.7.3.  LKH Download Type

   The LKH key packet is comprised of attributes representing different
   leaves in the LKH key tree.

   The following attributes are used to pass an LKH KEK array in the KD
   payload.  The attributes must follow the format defined in IKEv2
   (Section 3.3.5 of [RFC4306]).  In the table, attributes defined as TV
   are marked as Basic (B); attributes defined as TLV are marked as
   Variable (V).

                KEK Class                 Value      Type
                ---------                 -----      ----
                RESERVED                     0
                LKH_DOWNLOAD_ARRAY           1        V
                LKH_UPDATE_ARRAY             2        V
                SIG_ALGORITHM_KEY            3        V
                Standards Action            4-127
                Private Use               128-255

   If an LKH key packet is included in the KD payload, there must be
   only one present.

4.7.3.1.  LKH_DOWNLOAD_ARRAY

   This attribute is used to download a set of keys to a group member.
   It MUST NOT be included in a IKEv2 rekey message KD payload if the
   IKEv2 rekey is sent to more than the group member.  If an
   LKH_DOWNLOAD_ARRAY attribute is included in a KD payload, there must
   be only one present.

   This attribute consists of a header block, followed by one or more
   LKH keys.







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       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !  LKH Version  !          # of LKH Keys        !  RESERVED     !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !                             LKH Keys                          !
      ~                                                               ~
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The KEK_LKH attribute fields are defined as follows:

   o  LKH version (1 octet) -- Contains the version of the LKH protocol
      which the data is formatted in.  Must be one.

   o  Number of LKH Keys (2 octets) -- This value is the number of
      distinct LKH keys in this sequence.

   o  RESERVED (1 octet) -- Unused, set to zero.

   Each LKH Key is defined as follows:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !             LKH ID            !    Key Type   !    RESERVED   !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      ~                        Key Creation Date                      !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      ~                       Key expiration Date                     !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      ~                           Key Handle                          !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !                                                               !
      ~                            Key Data                           ~
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   o  LKH ID (2 octets) -- This is the position of this key in the
      binary tree structure used by LKH.

   o  Key Type (1 octet) -- This is the encryption algorithm for which
      this key data is to be used.  This value is specified in
      Section 4.4.3.

   o  RESERVED (1 octet) -- Unused, set to zero.

   o  Key Creation Date (4 octets) -- This is the time value of when
      this key data was originally generated.  A time value of zero
      indicates that there is no time before which this key is not



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      valid.

   o  Key Expiration Date (4 octets) -- This is the time value of when
      this key is no longer valid for use.  A time value of zero
      indicates that this key does not have an expiration time.

   o  Key Handle (4 octets) -- This is the randomly generated value to
      uniquely identify a key within an LKH ID.

   o  Key Data (variable length) -- This is the actual encryption key
      data, which is dependent on the Key Type algorithm for its format.
      If the mode of operation for the algorithm requires an
      Initialization Vector (IV), an explicit IV MUST be included in the
      Key Data field before the actual key.

   The Key Creation Date and Key expiration Dates MAY be zero.  This is
   necessary in the case where time synchronization within the group is
   not possible.

   The first LKH Key structure in an LKH_DOWNLOAD_ARRAY attribute
   contains the Leaf identifier and key for the group member.  The rest
   of the LKH Key structures contain keys along the path of the key tree
   in order from the leaf, culminating in the group KEK.

4.7.3.2.  LKH_UPDATE_ARRAY

   This attribute is used to update the keys for a group.  It is most
   likely to be included in a G-IKEv2 rekey message KD payload to rekey
   the entire group.  This attribute consists of a header block,
   followed by one or more LKH keys, as defined in Section 4.7.3.1.

   There may be any number of UPDATE_ARRAY attributes included in a KD
   payload.


















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       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !  LKH Version  !          # of LKH Keys        !  RESERVED     !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !            LKH ID             !           RESERVED2           !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !                           Key Handle                          !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !                            LKH Keys                           !
      ~                                                               ~
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   o  LKH version (1 octet) -- Contains the version of the LKH protocol
      which the data is formatted in.  Must be one.

   o  Number of LKH Keys (2 octets) -- This value is the number of
      distinct LKH keys in this sequence.

   o  RESERVED (1 octet) -- Unused, set to zero.

   o  LKH ID (2 octets) -- This is the node identifier associated with
      the key used to encrypt the first LKH Key.

   o  RESERVED2 (2 octets) -- Unused, set to zero.

   o  Key Handle (4 octets) -- This is the value to uniquely identify
      the key within the LKH ID which was used to encrypt the first LKH
      key.

   The LKH Keys are as defined in Section 4.7.3.1.  The LKH Key
   structures contain keys along the path of the key tree in order from
   the LKH ID found in the LKH_UPDATE_ARRAY header, culminating in the
   group KEK.  The Key Data field of each LKH Key is encrypted with the
   LKH key preceding it in the LKH_UPDATE_ARRAY attribute.  The first
   LKH Key is encrypted under the key defined by the LKH ID and Key
   Handle found in the LKH_UPDATE_ARRAY header.

4.7.3.3.  SIG_ALGORITHM_KEY

   The SIG_ALGORITHM_KEY class declares that the public key for this SPI
   is contained in the Key Packet Attribute, which may be useful when no
   public key infrastructure is available.  The signature algorithm that
   will use this key was specified in the GSAK payload.







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4.8.  Group Message Identification Payload

   The group message ID number is the message ID number a KS will use to
   send it first rekey request to the GM following the registration
   process.

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      ! Next Payload  !   RESERVED    !         Payload Length        !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !                       Group Message ID                        !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   o  Next Payload (1 octet) -- Identifier for the payload type of the
      next payload in the message.  If the current payload is the last
      in the message, then this field will be zero.

   o  RESERVED (1 octet) -- Unused, set to zero.

   o  Payload Length (2 octets) -- Length in octets of the current
      payload, including the generic payload header.

   o  Group Message ID (4 octets) -- Group message identifier for rekey
      message.

4.9.  Delete Payload

   There are occasions the GCKS may want to signal to receivers to
   delete policy at the end of a broadcast, or if policy has changed.
   Deletion of keys MAY be accomplished by sending an IKEv2 Delete
   Payload, section 3.11 of [RFC4306] as part of the G-IKEv2 Rekey
   Exchange.

   One or more Delete payloads MAY be placed following the HDR payload
   in the G-IKEv2 Rekey Exchange.

   The Protocol-ID field contains TEK protocol id values.  In order to
   delete a KEK SA, the value of zero MUST be used as the protocol id.
   Note that only one protocol id value can be defined in a Delete
   payload.  If a TEK and a KEK SA must be deleted, they must be sent in
   different Delete payloads.

4.10.  Notify Payload

   G-IKEv2 uses the same notify payload as specified in [RFC4306],
   section 3.10.




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   There are additional notify message types introduced by G-IKEv2 to
   commununicate error conditions and status.

   NOTIFY MESSAGES - ERROR TYPES          Value
   -------------------------------------------------------------------
   INVALID_GROUP_ID -                      TBD
   Indicates the group id sent during registration process is invalid.

   AUTHORIZATION_FAILED -                  TBD
   Sent in the response to GSA_AUTH message when authorization failed.

4.11.  Signature Payload

   The Signature Payload contains data generated by the digital
   signature function (selected during the SA establishment exchange),
   over some part of the rekey message.  This payload is used to verify
   the integrity of the data in the GCKS rekey message, and may be of
   use for non-repudiation services.  Below shows the format of the
   Signature Payload.

                           1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      ! Next Payload  !   RESERVED    !         Payload Length        !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      !                                                               !
      ~                         Signature Data                        ~
      !                                                               !
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Signature Payload fields are defined as follows:

   o  Next Payload (1 octet) - Identifier for the payload type of the
      next payload in the message.  If the current payload is the last
      in the message, then this field will be 0.

   o  RESERVED (1 octet) - Unused, set to 0.

   o  Payload Length (2 octets) - Length in octets of the current
      payload, including the generic payload header.

   o  Signature Data (variable length) - Data that results from applying
      the digital signature function to the GCKS rekey message.








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5.  Security Considerations

5.1.  GSA registration and secure channel

   G-IKEv2 registration exchange uses IKEv2 IKE_SA_INIT and IKE_AUTH
   inheriting all the security considerations documented in [RFC4306]
   section 5 Security Considerations, including authentication,
   confidentiality, protection against man-in-the middle, protection
   against replay/reflection attacks, and denial of service protection.
   In addition, G-IKEv2 brings in the capability to authorize a
   particular group member regardless of whether they have the IKEv2
   credentials.

5.2.  GSA maintenance channel

   The GSA maintenance channel is cryptographically and integrity
   protected using the cryptographic algorithm and key negotiagated in
   the GSA member registration exchanged.

5.2.1.  Authentication/Authorization

   Authentication is implicit, the public key of the identity is
   distributed during the registration, and the receiver of the rekey
   message uses that public key and identity to verify the message is
   come from the authorized GCKS.

5.2.2.  Confidentiality

   Confidentiality is provided by distributing a confidentiality key as
   part of the GSA member registration exchange.

5.2.3.  Man-in-the-Middle Attack Protection

   GSA maintenance channel is integrity protected by using digital
   signature.

5.2.4.  Replay/Reflection Attack Protection

   G-IKEv2 will use the message ID in the IKEv2 header to provide anti-
   replay protection for GSA_REKEY exchange.  During registration, the
   GSA_AUTH response will include the message ID of the current rekey
   message in its Group Message ID payload.  The group member MUST only
   accept the GSA_REKEY request with the message ID greater than the
   previous rekey message.  The message ID resets to a value of one with
   a new KEK attribute.  The first packet sent for a given Rekey SA will
   have a message ID of 1.

   Since the multicast rekey message does not require a response and it



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   is not possible to know how many rekey message that a particular GM
   may miss, so the KS and GM MUST set their window size to maximum
   value (0xffffffff).
















































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6.  IANA Considerations

6.1.  New registries

   A new set of registries are created for this draft.

   KEK Attributes Registry, see Section 4.4.1

   KEK Management Algorithm Registry, see Section 4.4.2

   KEK Algorithm Registry, see Section 4.4.3

   SIG Hash Algorithm Registry, see Section 4.4.6

   SIG Algorithm Registry, see Section 4.4.7

   GSA TEK Payload Protocol ID Type Registry, see Section 4.5

   GSA Life Attributes Registry, see Section 4.5

   Key Download Type Registry, see Section 4.7

   TEK Download Type Registry, see Section 4.7.1

   KEK Download Type Registry, see Section 4.7.2

   LKH Download Type Registry, see Section 4.7.3

6.2.  New payload and exchange types to existing IKEv2 registry

   The present document describes new IKEv2 Next Payload types, see
   Section 4.1

   The present document describes new IKEv2 Exchanges types, see
   Section 4.1

   The present document describes new IKEv2 Notify Payload types, see
   Section 4.10

6.3.  Payload Types

   The present document defines new ISAKMP Next Payload types.  See
   Section 5.0 for the payloads defined in this document, including the
   Next Payload values defined by the IANA to identify these payloads.







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6.4.  New Name spaces

   The present document describes many new name spaces for use in the
   GDOI payloads.  Those may be found in subsections under Section 5.0.
   A new GDOI registry has been created for these name spaces.

   Portions of name spaces marked "RESERVED" are reserved for IANA
   allocation.  New values MUST be added due to a Standards Action as
   defined in [RFC2434].

   Portions of name spaces marked "Private Use" may be allocated by
   implementations for their own purposes.







































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7.  Acknowledgements

   The authors thank Lakshminath Dondeti and Jing Xiang for originating
   the GKDP document and providing the basis behind the protocol.

   The authors also thank reviewers: Brian Weis, Kavitha Kamarthy, Lewis
   Chen, Cheryl Madson












































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8.  References

8.1.  Normative References

   [FIPS186-2]
              "Digital Signature Standard (DSS)", United States of
              America, National Institute of Science and
              Technology Federal Information Processing Standard (FIPS)
              186-2, January 2001.

   [FIPS197]  "Advanced Encryption Standard (AES)", United States of
              America, National Institute of Science and
              Technology Federal Information Processing Standard (FIPS)
              197, November 2001.

   [RSA]      TRSA Laboratories, "PKCS #1 v2.0: RSA Encryption
              Standard", 1998.

   [SP800-38A]
              Dworkin, M., "Recommendation for Block Cipher Modes of
              Operation", United States of America, National Institute
              of Science and Technology NIST Special Publication 800-38A
              2001 Edition, December 2001.

   [SP800-38D]
              Dworkin, M., "Recommendation for Block Cipher Modes of
              Operation", United States of America, National Institute
              of Science and Technology NIST Special Publication 800-38D
              2007 Edition, December 2001.

8.2.  Informative References

   [IKE-HASH]
              Kivienen, T., "Fixing IKE Phase 1 & 2 Authentication
              HASHs", November 2001, <http://tools.ietf.org/html/
              draft-ietf-ipsec-ike-hash-revised-03>.

   [RFC2407]  Piper, D., "The Internet IP Security Domain of
              Interpretation for ISAKMP", RFC 2407, November 1998.

   [RFC2408]  Maughan, D., Schneider, M., and M. Schertler, "Internet
              Security Association and Key Management Protocol
              (ISAKMP)", RFC 2408, November 1998.

   [RFC2409]  Harkins, D. and D. Carrel, "The Internet Key Exchange
              (IKE)", RFC 2409, November 1998.

   [RFC2434]  Narten, T. and H. Alvestrand, "Guidelines for Writing an



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              IANA Considerations Section in RFCs", BCP 26, RFC 2434,
              October 1998.

   [RFC2627]  Wallner, D., Harder, E., and R. Agee, "Key Management for
              Multicast: Issues and Architectures", RFC 2627, June 1999.

   [RFC3547]  Baugher, M., Weis, B., Hardjono, T., and H. Harney, "The
              Group Domain of Interpretation", RFC 3547, July 2003.

   [RFC3686]  Housley, R., "Using Advanced Encryption Standard (AES)
              Counter Mode With IPsec Encapsulating Security Payload
              (ESP)", RFC 3686, January 2004.

   [RFC4046]  Baugher, M., Canetti, R., Dondeti, L., and F. Lindholm,
              "Multicast Security (MSEC) Group Key Management
              Architecture", RFC 4046, April 2005.

   [RFC4106]  Viega, J. and D. McGrew, "The Use of Galois/Counter Mode
              (GCM) in IPsec Encapsulating Security Payload (ESP)",
              RFC 4106, June 2005.

   [RFC4306]  Kaufman, C., "Internet Key Exchange (IKEv2) Protocol",
              RFC 4306, December 2005.

   [RFC4309]  Housley, R., "Using Advanced Encryption Standard (AES) CCM
              Mode with IPsec Encapsulating Security Payload (ESP)",
              RFC 4309, December 2005.

   [RFC4430]  Sakane, S., Kamada, K., Thomas, M., and J. Vilhuber,
              "Kerberized Internet Negotiation of Keys (KINK)",
              RFC 4430, March 2006.

   [RFC4543]  McGrew, D. and J. Viega, "The Use of Galois Message
              Authentication Code (GMAC) in IPsec ESP and AH", RFC 4543,
              May 2006.
















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Appendix A.  Differences between G-IKEv2 and RFC 3547

   POP/CERT - The Proof of Possession and associated Certificate
   payloads are no longer needed since the GCKS authorization capability
   adequately provides the authorization.

   KE Payload - The KE payload is no longer needed with the availability
   of newer algorithms such as AES and GCM which provide adequate
   protection therefore not needing the PFS capability the KE payload
   offers.

   SEQ - The SEQ payload is no longer required since IKEv2 provides the
   replay protection capability using the message ID in the header.

   DOI/Situation - The DOI and Situation fields in the SA payload are no
   longer needed in the G-IKEv2 protocol as port 848 will distinguish
   the IKEv2 messages from the G-IKEv2 messages.


































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Authors' Addresses

   Sheela Rowles
   Cisco Systems
   170 W. Tasman Drive
   San Jose, California  95134-1706
   USA

   Phone: +1-408-527-7677
   Email: sheela@cisco.com


   Aldous Yeung (editor)
   Cisco Systems
   170 W. Tasman Drive
   San Jose, California  95134-1706
   USA

   Phone: +1-408-853-2032
   Email: cyyeung@cisco.com


   Paulina Tran
   Cisco Systems
   170 W. Tasman Drive
   San Jose, California  95134-1706
   USA

   Phone: +1-408-526-8902
   Email: ptran@cisco.com





















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