MSEC Working Group S. Rowles
Internet-Draft A. Yeung, Ed.
Intended status: Standards Track P. Tran
Expires: September 15, 2011 Cisco Systems
March 14, 2011
Group Key Management using IKEv2
draft-yeung-g-ikev2-02
Abstract
This document presents a new group key distribution protocol, using
group key distribution RFC 3547 with IKEv2 RFC 5996. 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 Group Controller Key Server to a member of the
group.
Status of this Memo
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This Internet-Draft will expire on September 15, 2011.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
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to this document. Code Components extracted from this document must
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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. GSA_INIT exchange . . . . . . . . . . . . . . . . . . 8
3.1.2. GSA_AUTH exchange . . . . . . . . . . . . . . . . . . 9
3.1.3. GSA_PULL Exchange . . . . . . . . . . . . . . . . . . 10
3.1.4. IKEv2 Header Initialization . . . . . . . . . . . . . 10
3.1.5. GM Registration Operations . . . . . . . . . . . . . . 10
3.1.6. GCKS Registration Operations . . . . . . . . . . . . . 11
3.2. Counter-based modes of operation . . . . . . . . . . . . . 12
3.3. G-IKEv2 group maintenance channel . . . . . . . . . . . . 14
3.3.1. G-IKEv2 GSA_PUSH exchange . . . . . . . . . . . . . . 14
3.3.2. Forward and Backward Access Control . . . . . . . . . 15
3.3.3. Forward Access Control Requirements . . . . . . . . . 15
3.3.4. Deletion of SAs . . . . . . . . . . . . . . . . . . . 16
3.3.5. GSA_PUSH GCKS Operations . . . . . . . . . . . . . . . 17
3.3.6. GSA_PUSH GM Operations . . . . . . . . . . . . . . . . 17
4. Header and Payload Formats . . . . . . . . . . . . . . . . . . 18
4.1. The G-IKEv2 Header . . . . . . . . . . . . . . . . . . . . 18
4.2. IDgroup Payload . . . . . . . . . . . . . . . . . . . . . 18
4.3. Group Security Association Payload . . . . . . . . . . . . 18
4.3.1. Payloads following the GSA Payload . . . . . . . . . . 19
4.4. KEK Payload . . . . . . . . . . . . . . . . . . . . . . . 20
4.4.1. KEK Attributes . . . . . . . . . . . . . . . . . . . . 21
4.4.2. KEK_MANAGEMENT_ALGORITHM . . . . . . . . . . . . . . . 21
4.4.3. KEK_ALGORITHM . . . . . . . . . . . . . . . . . . . . 22
4.4.3.1. KEK_ALG_AES_CBC . . . . . . . . . . . . . . . . . 22
4.4.3.2. KEK_ALG_AES_GCM . . . . . . . . . . . . . . . . . 22
4.4.4. KEK_KEY_LENGTH . . . . . . . . . . . . . . . . . . . . 22
4.4.5. KEK_KEY_LIFETIME . . . . . . . . . . . . . . . . . . . 23
4.4.6. AUTH_HASH_ALGORITHM . . . . . . . . . . . . . . . . . 23
4.5. GSA TEK Payload . . . . . . . . . . . . . . . . . . . . . 23
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4.5.1. TEK ESP and AH Protocol-Specific Payload . . . . . . . 24
4.6. GSA Group Associated Policy Payload . . . . . . . . . . . 26
4.6.1. ACTIVATION_TIME_DELAY/DEACTIVATION_TIME_DELAY . . . . 27
4.6.2. Sender_ID_REQUEST . . . . . . . . . . . . . . . . . . 28
4.7. Key Download Payload . . . . . . . . . . . . . . . . . . . 28
4.7.1. TEK Download Type . . . . . . . . . . . . . . . . . . 29
4.7.1.1. TEK_ALGORITHM_KEY . . . . . . . . . . . . . . . . 30
4.7.1.2. TEK_INTEGRITY_KEY . . . . . . . . . . . . . . . . 30
4.7.1.3. TEK_SOURCE_AUTH_KEY . . . . . . . . . . . . . . . 30
4.7.2. KEK Download Type . . . . . . . . . . . . . . . . . . 30
4.7.2.1. KEK_ALGORITHM_KEY . . . . . . . . . . . . . . . . 31
4.7.2.2. AUTH_ALGORITHM_KEY . . . . . . . . . . . . . . . . 31
4.7.3. LKH Download Type . . . . . . . . . . . . . . . . . . 31
4.7.3.1. LKH_DOWNLOAD_ARRAY . . . . . . . . . . . . . . . . 32
4.7.3.2. LKH_UPDATE_ARRAY . . . . . . . . . . . . . . . . . 34
4.7.3.3. AUTH_ALGORITHM_KEY . . . . . . . . . . . . . . . . 35
4.7.4. SID Download Type . . . . . . . . . . . . . . . . . . 35
4.7.4.1. NUMBER_OF_SID_BITS . . . . . . . . . . . . . . . . 35
4.7.4.2. SID_VALUE . . . . . . . . . . . . . . . . . . . . 35
4.7.4.3. GM Semantics . . . . . . . . . . . . . . . . . . . 35
4.7.4.4. GCKS Semantics . . . . . . . . . . . . . . . . . . 36
4.8. Sequence Number Payload . . . . . . . . . . . . . . . . . 36
4.9. Delete Payload . . . . . . . . . . . . . . . . . . . . . . 37
4.10. Notify Payload . . . . . . . . . . . . . . . . . . . . . . 37
4.11. Authentication Payload . . . . . . . . . . . . . . . . . . 37
5. Security Considerations . . . . . . . . . . . . . . . . . . . 38
5.1. GSA registration and secure channel . . . . . . . . . . . 38
5.2. GSA maintenance channel . . . . . . . . . . . . . . . . . 38
5.2.1. Authentication/Authorization . . . . . . . . . . . . . 38
5.2.2. Confidentiality . . . . . . . . . . . . . . . . . . . 38
5.2.3. Man-in-the-Middle Attack Protection . . . . . . . . . 38
5.2.4. Replay/Reflection Attack Protection . . . . . . . . . 38
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 39
6.1. New registries . . . . . . . . . . . . . . . . . . . . . . 39
6.2. New payload and exchange types to existing IKEv2
registry . . . . . . . . . . . . . . . . . . . . . . . . . 39
6.3. Payload Types . . . . . . . . . . . . . . . . . . . . . . 39
6.4. New Name spaces . . . . . . . . . . . . . . . . . . . . . 39
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 41
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 42
8.1. Normative References . . . . . . . . . . . . . . . . . . . 42
8.2. Informative References . . . . . . . . . . . . . . . . . . 42
Appendix A. Differences between G-IKEv2 and RFC 3547 . . . . . . 44
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Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 45
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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 [RFC5996]. The GCKS
downloads policy and keys after the GCKS authenticates the client.
The initial exchange uses IKE_SA_INIT exchange in IKEv2. The new
payloads for G-IKEv2 are added in the IKE_AUTH exchange. The result
of the IKE_AUTH is that the GCKS downloads policy and keys for the
group to the Group Members (GM). This document will reference the
IKEv2 RFCs [5996 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];
these documents are obsoleted and replaced by a new version of the
IKE protocol defined in RFC 5996. G-IKEv2 provides group key
management between the group member and group controller key server
using the new IKEv2 protocol and inherits the following key
advantages over GDOI:
1. Provide a simple mechanism for the 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 documented 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. GSA (Group Security Association) - The GCKS sends the group
policy to the GM using this payload.
3. 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.
4. GSA GAP (Group Associated Policy) - The GAP payload allows for
the request of sender specific information as well as the
distribution of group-wise policy [Section 4.6].
5. 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.
6. KD (Key Download) - The GCKS sends the control and data keys to
the GM using the KD payload.
7. SEQ (Sequence Number Payload) - The SEQ payload provides anti-
replay protection for the rekey message.
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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 management between
group member and the group controller 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, GSA_INIT and
GSA_AUTH. Each exchange consists of request/response pairs. The
first exchange GSA_INIT is the same as IKE_SA_INIT is defined in
IKEv2 [RFC5996]. This exchange negotiates cryptographic algorithms,
exchanges nonces and does a 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 GSA_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
GSA Group Security Association
HDR IKEv2 Header
IDg Identification - Group
IDi Identification - Initiator
IDr Identification - Responder
KD Key Download
KE Key Exchange
Ni, Nr Nonce SA Security Association
SEQ Sequence Number of rekey message
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. GSA_INIT exchange
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Member (Initiator) GCKS (Responder)
-------------------- ------------------
HDR, SAi1, KEi, Ni -->
<-- HDR, SAr1, KEr, Nr, [CERTREQ,]
The group member initiates the GSA_INIT exchange to the GCKS to
negotiate cryptographic algorithms, exchange nonces, and perform a
Diffie-Hellman exchange in the same manner as the IKE_SA_INIT
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, GAP } -->
After an unauthenticated secure channel is established by IKE_SA_INIT
exchange, the member initiates a registration request to join a group
indicated by the IDg payload. The GM MUST include the GAP payload to
request resources from the GCKS. Note the GAP payload is used by the
initiator to request GCKS resources, and the GAP payload is sent by
the GCKS to provide group based information.
<-- HDR, SK { IDr, [CERT,] AUTH,
[SEQ,] GSA, KD }
The GCKS MAY inform the group member the current value of the rekey
sequence number using the SEQ payload. The first GSA_PUSH sequence
number the member receives MUST be greater than SEQ value. The SEQ
payload MUST be present if the GSA payload contains a 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 contains the KEK and/or TEK policy,
and/or the policy in the GAP and the authentication transforms. The
KD payload contains the KEK and/or TEK keying material. 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
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the presence of the GSA KEK attribute, then the KD will contain the
GSA KEK; if one or more Data-security SAs are defined in the GSA
payload, the KD will contain the TEKs. The GAP payload may also
provide the ATD or DTD providing specifying activation and
deactivation delays for SAs generated from the TEKs. The KD payload
MAY specify the sender specific information if any of the AES
counter-based modes are being used to provide unique sender
information to the GMs.
G-IKEv2 member registration may have a few more messages exchanged 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 IKE_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. GSA_PULL Exchange
When a secure channel is already established between GM and KS, the
GM registration for another group can reuse the established secure
channel. In this scenario the GM will use the PULL exchange by
including the desired group ID (IDg) to request data security keys
(TEKs) and/or group key encrypting keys (KEKs) from the GCKS. The GM
MUST also include the GAP payload to request resources from the GCKS.
Initiator (Member) Responder (GCKS)
-------------------- ------------------
HDR, SK {IDg, GAP } -->
<-- HDR, SK { [SEQ], GSA, KD }
3.1.4. IKEv2 Header Initialization
The Major Version is (2) and Minor Version number (0) according to
IKEv2 [RFC5996], and maintained in this document. The G-IKEv2 GSA-
INIT uses the SPI according to IKEv2 [RFC5996],section 2.6.
3.1.5. GM Registration Operations
A G-IKEv2 Initiator (GM) requesting registration contacts the GCKS
using the GSA_INIT exchange and receives the response from the GCKS.
This exchange is unchanged from the IKE_SA_INIT in IKEv2 protocol.
Upon completion of parsing and verifying the GSA_INIT response, the
GM sends the GSA_AUTH message with the IKEv2 payloads from
IKE_SA_AUTH along with the Group ID and the GAP payload informing the
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GCKS of the group the initiator wishes to join. The initiator
determines how many Sender-ID values it would like to receive and
adds the SENDER_ID_REQUEST in the GAP payload since there is a
possibility the Data Security SA supports a counter mode cipher
[section 3.2]. The initiator then parses the response from the GCKS
authenticating the exchange using the IKEv2 payloads, then accessing
the SEQ, if present, GSA, and KD.
If SEQ payload is present, the sequence number in the SEQ payload
must be checked against any previously received sequence number for
this group. If it is less than the previously received number, it
should be considered stale and ignored. This could happen if two
GSA_AUTH exchanges happened in parallel, and the sequence number
changed.
The GSA is parsed providing the TEK and/or KEK and/or the GAP policy.
The GSA payload contains policy describing the security protocol and
cryptographic protocols used by the group. This policy describes the
Re-key SA, if present, Data-security SAs, and other group policy. If
the policy in the GSA payload is acceptable to the GM, it continues
parsing the remaining payload. Otherwise, the GM SHOULD tear down
the session after notifying the GCKS. Finally the KD is parsed
providing the keying material for the TEK and/or KEK. The GM
interprets the KD key packets, where each key packet includes the
keying material for SAs distributed in the GSA payload. Keying
material is matched by comparing the SPIs in the key packets to SPIs
previously sent in the GSA payloads. Once TEK keys and policy are
matched, the GM provides them to the data security subsystem, and it
is ready to send or receive packets matching the TEK policy. If this
group has a KEK, the KEK policy and keys are marked as ready for use,
and the GM knows to expect the sequence number reset to 1 with the
next Rekey SA, which will be encrypted with the new KEK attribute.
The GM is now ready to receive GSA_PUSH messages.
3.1.6. GCKS Registration Operations
A G-IKEv2 GCKS passively listens for incoming requests from group
members. The GCKS receives the GSA_INIT request message and responds
with the GSA_INIT response and authenticates the GM with the same
properties as IKEv2.
Upon receiving the GSA_AUTH message, and after authenticating the
peer, the GCKS locates the group the GM wishes to join, extracts the
policy for that group, and includes the SEQ payload (if the GCKS
sends rekey messages), generates the policy in the GSA payload,
including the GSA KEK, optionally the GAP, and/or SA TEK payloads
according to GCKS policy., along with the keying material in the KD
payload. The GAP payload MAY include the ATD or DTD [section 4.6.1]
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if it is desired to address the activation and deactivation time
delays of the TEK SA. If one or more Data Security SAs distributed
in the GSA payload included a counter mode of operation, the GCKS
includes at least one SID value in the KD payload, and possibly more
depending on the request received in the GAP payload requesting the
number of SIDs from the GM. If the GCKS desires authorization, the
GCKS authorizes the peer against the specified credentials before
sending the GSA_AUTH response.
If the GCKS receives a GSA PULL exchange with a request to register
the same GM to another group, the GCKS will need to authorize the GM
with the new group (IDg) and respond with corresponding group policy
and keys. If the GCKS fails to authorize the GM, it will respond
with the AUTHORIZATION_FAILED notify message.
3.2. Counter-based modes of operation
Several new counter-based modes of operation have been specified for
ESP (e.g., AES-CTR [RFC3686], AES-GCM [RFC4106], AES-CCM [RFC4309],
AES-GMAC [RFC4543]) and AH (e.g., AES-GMAC [RFC4543]). These
counter-based modes require that no two senders in the group ever
send a packet with the same Initialization Vector (IV) using the same
cipher key and mode. This requirement is met in GDOI when the
following requirements are met:
o The GCKS distributes a unique key for each Data-Security SA.
o The GCKS uses the method described in [RFC6054], which assigns each
sender a portion of the IV space by provisioning each sender with one
or more unique SID values.
When at least one Data-Security SA included in the group policy
includes a counter-mode, the GCKS automatically allocates and
distributes one SID to each group member acting in the role of sender
on the Data-Security SA. The SID value is used exclusively by the
group member to which it was allocated. The group member uses the
same SID for each Data-Security SA specifying the use of a counter-
based mode of operation. A GCKS MUST distribute unique keys for each
Data-Security SA including a counter-based mode of operation in order
to maintain a unique key and nonce usage.
A group member MUST request as many SIDs matching the number of
encryption modules in which it will be installing the TEKs in the
outbound direction. Alternatively, a group member MAY request more
than one SID and use them serially. This could be useful when it is
anticipated that the group member will exhaust their range of Data-
Security SA nonces using a single SID too quickly (e.g., before the
time-based policy in the TEK expires).
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When group policy includes a counter-based mode of operation, a GCKS
SHOULD use the following method to allocate SID values, which ensures
that each SID will be allocated to just one group member.
1. A GCKS maintains an SID-counter, which records the SIDs that have
been allocated. SIDs are allocated sequentially, with the first SID
allocated to be zero.
2. Each time an SID is allocated, the current value of the counter
is saved and allocated to the group member. The SID-counter is then
incremented in preparation for the next allocation.
3. When the GCKS specifies a counter-based mode of operation in the
Data Security SA, and a group member is a sender, a group member may
request a count of SIDs in a GAP payload. When the GCKS receives
this request, it increments the SID- counter once for each requested
SID, and distributes each SID value to the group member.
4. A GCKS allocates new SID values for each GSA_PULL exchange
originated by a sender, regardless of whether a group member had
previously contacted the GCKS. In this way, the GCKS does not have a
requirement of maintaining a record of which SID values it had
previously allocated to each group member. More importantly, since
the GCKS cannot reliably detect whether the group member had sent
data on the current group Data-Security SAs it does not know what
Data-Security counter-mode nonce values that a group member has used.
By distributing new SID values, the key server ensures that each time
a conforming group member installs a Data- Security SA it will use a
unique set of counter-based mode nonces.
5. When the SID-counter maintained by the GCKS reaches its final SID
value, no more SID values can be distributed. Before distributing
any new SID values, the GCKS MUST delete the Data- Security SAs for
the group, followed by creation of new Data- Security SAs, and
resetting the SID-counter to its initial value.
6. The GCKS SHOULD send a GSA_PUSH message deleting all Data-
Security SAs and the Rekey SA for the group. This will result in the
group members initiating a new GSA_PULL exchange, in which they will
receive both new SID values and new Data-Security SAs. The new SID
values can safely be used because they are only used with the new
Data-Security SAs. Note that deletion of the Rekey SA is necessary
to ensure that group members receiving a GSA_PUSH exchange before the
re-register do not inadvertently use their old SIDs with the new
Data-Security SAs. Using the method above, at no time can two group
members use the same IV values with the same Data-Security SA key.
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3.3. 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.
3.3.1. G-IKEv2 GSA_PUSH exchange
The GCKS initiates the G-IKEv2 Rekey securely using IP multicast.
Since multicast rekey does not require a response and it sends to
multiple GMs, G-IKEv2 Rekeying SHOULD not support windowing. The
anti-replay protection is supported by the SEQ payload. The GCKS
Rekey message replaces the Rekey GSA KEK or KEK array, and/or creates
a new Data-Security GSA TEK. The SID Download attribute [section
4.7.4] in the Key Download payload 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 { SEQ, GSA, KD, AUTH }
HDR is defined in Section 4.1. The SEQ payload is defined in
Section 4.8. 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 AUTH 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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3.3.2. 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].
3.3.3. 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.
3.3.4. 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 a 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 { SEQ, DEL, [GSA], [KD], AUTH }
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 payload with a spi of zero
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and protocol_id of zero, indicating that the KEK SA should be
deleted.
3.3.5. GSA_PUSH 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 the rekey message with value of the SEQ payload that is one
greater than the previous rekey. If the message is using a new KEK
attribute, the SEQ is reset to 1 in this message. The GSA and KD
follow with the same characteristics as in the GSA Registration
exchange. The AUTH 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.
3.3.6. GSA_PUSH GM Operations
The group member receives the Rekey Message from the GCKS, decrypts
the message using the current KEK, validates the signature using the
public key retrieved in a previous G-IKEv2 exchange, verifies the
value in SEQ payload is one or more greater than that of the last GSA
rekey received, and processes the GSA and KD payloads. The group
member then downloads the new data security SA and/or new Rekey GSA.
The parsing of the payloads is identical to the registration
exchange.
If the SA payload includes Data-Security SA including a counter-modes
of operation and the receiving group member is a sender for that SA,
the group member uses its current SID value with the Data-Security
SAs to create counter-mode nonces. If it is a sender and does not
hold a current SID value, it MUST NOT install the Data-Security SAs.
It MAY initiate a GSA_PULL exchange to the GCKS in order to obtain an
SID value (along with current group policy).
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4. Header and Payload Formats
Refer to IKEv2 [RFC5996] for existing payloads.
4.1. The G-IKEv2 Header
G-IKEv2 uses the same IKE header format as specified in RFC 5996
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
GSA KEK Payload (GSAK) TBD
GSA GAP Payload (GGAP) TBD
GSA TEK Payload (GSAT) TBD
Key Download (KD) TBD
Sequence Number Payload (SEQ) TBD
New exchange types IKE_AUTH and GSA_REKEY are added to the IKEv2
[RFC5996] protocol.
Exchange Type Value
-------------- -----
GSA_INIT TBD
GSA_AUTH TBD
GSA_PULL TBD
GSA_PUSH TBD
Major Version is 2 and Minor Version is 0 as in IKEv2 [RFC5996]. IKE
SA initiator SPI, IKE SA responder SPI, Flags, Message Id are as
specified in [RFC5996].
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
[RFC5996] 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 4.3.1 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 Payload, zero or more GAP Payloads, and zero
or more GSA TEK Payloads, where either one GSA KEK or GSA TEK payload
MUST be present. When present, the order of the SA attribute
payloads MUST be: KEK, GAP(s), TEK(s).
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
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the same group and multiple streams to be associated with a session
(e.g., video, audio, and text) but each with individual security
association policy.
A GAP payload allows for the distribution of group-wise policy, such
as instructions as to when to activate and de-activate SAs.
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
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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 SPIs are assigned by the
GCKS.
o Source & Destination Traffic Selectors - Substructures describing
the source and destination of the identities. These identities
refer to the source and destination of the next KEK rekey SA.
Defined format and values are specified by IKEv2 [RFC5996],
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 [RFC5996] 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
AUTH_HASH_ALGORITHM 5 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 and AUTH_HASH_ALGORITHM
(except for DSA based algorithms).
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. AUTH_HASH_ALGORITHM
AUTH_HASH_ALGORITHM specifies the AUTH payload hash algorithm. The
following tables define the algorithms for AUTH_HASH_ALGORITHM.
Algorithm Type Value
-------------- -----
RESERVED 0
AUTH_HASH_SHA256 1
AUTH_HASH_SHA384 2
AUTH_HASH_SHA512 3
Standards Action 4-127
Private Use 128-255
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.
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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
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 ESP and AH 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:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
! SPI !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
| |
~ <Source Traffic Selector> ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ <Destination Traffic Selector> |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
| |
~ <Transform> ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
! GSA Life 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 [RFC5996], section
3.13.1.
o Transform -- A substructure specifies the transform information.
The format and values are defined in IKEv2 [RFC5996], 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
[RFC5996], section 3.3.5.
Attribute Types
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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 downloaded under
the association (AH or ESP) must be re-rekeyed. The life
type values are:
RESERVED 0
seconds 1
kilobytes 2
Values 3-61439 are reserved to IANA and will be allocated using
the Standards Action method. 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.
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.
The policy relevant to all group members can be distributed in the
G-IKEv2 Registration exchange or the GSA Push exchange, but the
sender specific information MUST only be sent in a G-IKEv2
Registration Exchange. Additionally, a group member sometimes has
the need to make policy requests for resources of the GCKS in the
GSA_AUTH request.
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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
[RFC5996].
Several group associated policy attributes are defined below. A
G-IKEv2 implementation MUST abort if it encounters an attribute or
capability that it does not understand.
4.6.1. ACTIVATION_TIME_DELAY/DEACTIVATION_TIME_DELAY
Section 4.2.1 of RFC 5374 specifies a key rollover method that
requires two values be given it from the group key management
protocol. The ACTIVATION_TIME_DELAY attribute allows a GCKS to set
the Activation Time Delay (ATD) for SAs generated from TEKs. The ATD
defines how long after receiving new SAs that they are to be
activated by the GM. The ATD value is in seconds.
The DEACTIVATION_TIME_DELAY allows the GCKS to set the Deactivation
Time Delay (DTD) for previously distributed SAs. The DTD defines how
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long after receiving new SAs that it should deactivate SAs that are
destroyed by the re-key event. The value is in seconds.
The values of ATD and DTD are independent. However, the DTD value
should be larger, which allows new SAs to be activated before older
SAs are deactivated. Such a policy ensures that protected group
traffic will always flow without interruption.
4.6.2. Sender_ID_REQUEST
The SENDER_ID_REQUEST attribute is used by a group member to request
SIDs during the G-IKEv2 Registration message, and includes a count of
how many SID values it desires.
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.
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.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-!
! 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.
Key Download Type Value
----------------- -----
RESERVED 0
TEK 1
KEK 2
LKH 3
SID TBD-7
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 [RFC5996]). In the table, attributes defined
as TV are marked as Basic (B); attributes defined as TLV are marked
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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.
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 member. 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 [RFC5996]). In the table, attributes defined
as TV are marked as Basic (B); attributes defined as TLV are marked
as Variable (V).
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KEK Class Value Type
--------- ----- ----
RESERVED 0
KEK_ALGORITHM_KEY 1 V
AUTH_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.
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. AUTH_ALGORITHM_KEY
The AUTH_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 [RFC5996]). In the table, attributes defined as TV
are marked as Basic (B); attributes defined as TLV are marked as
Variable (V).
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KEK Class Value Type
--------- ----- ----
RESERVED 0
LKH_DOWNLOAD_ARRAY 1 V
LKH_UPDATE_ARRAY 2 V
AUTH_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.
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:
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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 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
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
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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.
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
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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. AUTH_ALGORITHM_KEY
The AUTH_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.
4.7.4. SID Download Type
This attribute is used to download one or use more Sender-ID (SID)
values for the exclusive use of a group member.
KEK Class Value Type
--------- ----- ----
RESERVED 0
NUMBER_OF_SID_BITS 1 V
SID_VALUE 2 V
Standards Action 3-128
Private Use 129-255
Unassigned 256-32767
Because a SID value is intended for a single group member, the SID
Download type MUST NOT be distributed in a GROUPKEY_PUSH message
distributed to multiple group members.
4.7.4.1. NUMBER_OF_SID_BITS
The NUMBER_OF_SID_BITS class declares how many bits of the cipher
nonce in which to represent an SID value. This value applied to each
SID value is distributed in the SID Download.
4.7.4.2. SID_VALUE
The SID_VALUE class declares a single SID value for the exclusive use
of the a group member. Multiple SID_VALUE attributes MAY be included
in a SID Download.
4.7.4.3. GM Semantics
The SID_VALUE attribute value distributed to the group member MUST be
used by that group member as the SID field portion of the IV for all
Data-Security SAs including a counter-based mode of operation
distributed by the GCKS as a part of this group. When the Sender-
Specific IV (SSIV) field for any Data-Security SA is exhausted, the
group member MUST no longer act as a sender on that SA using its
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active SID. The group member SHOULD re-register, at which time the
GCKS will issue a new SID to the group member, along with either the
same Data-Security SAs or replacement ones. The new SID replaces the
existing SID used by this group member, and also resets the SSIV
value to its 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 an SID Download Type KD payload
present in a GSA-PUSH message.
4.7.4.4. GCKS Semantics
If any KD payload includes keying material that is associated with a
counter-mode of operation, an SID Download Type KD payload containing
at least one SID_VALUE attribute MUST be included. The GCKS MUST NOT
send the SID Download Type KD payload as part of a GSA-PUSH message,
because distributing the same sender-specific policy to more than one
group member will reduce the security of the group.
4.8. Sequence Number Payload
The Sequence Number Payload (SEQ) provides an anti-replay protection
for GSA rekey messages.
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 !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
! Sequence Number !
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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 Sequence Number (4 octets) -- The sequence number of the rekey
message.
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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 [RFC5996] 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 [RFC5996],
section 3.10.
There are additional notify message types introduced by G-IKEv2 to
communicate 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 IKE_AUTH message when authorization failed.
NOTIFY MESSAGES - STATUS TYPES Value
-------------------------------------------------------------------
GIKEv2_REGISTRATION - TBD
See Section 3.1.3
GIKEv2_REKEY - TBD
See Section 3.2.1
4.11. Authentication Payload
G-IKEv2 uses the same Authentication payload as specified in
[RFC5996], section 3.8, to sign the 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 [RFC5996]
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 negotiated 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
The GSA rekey message includes a monotonically increasing sequence
number to protect against replay and reflection attacks. A group
member will recognize a replayed message by comparing the sequence
number to that of the last received rekey message, any rekey message
contains sequence number less than or equal to the last received
value SHOULD be discarded. Implementations SHOULD keep a record of
recently received GSA rekey messages for this comparison.
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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
AUTH Hash Algorithm Registry, see Section 4.4.6
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.
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.
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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, and Raghunandan P.
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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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Internet-Draft G-IKEv2 March 2011
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.
[RFC5996] Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen,
"Internet Key Exchange Protocol Version 2 (IKEv2)",
RFC 5996, September 2010.
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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.
SIG Payload - The AUTH payload is used for the same purpose instead.
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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