One document matched: draft-ietf-dhc-sedhcpv6-13.xml
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<rfc category="std" docName="draft-ietf-dhc-sedhcpv6-13" ipr="trust200902">
<front>
<title abbrev="SeDHCPv6">Secure DHCPv6</title>
<author fullname="Sheng Jiang" initials="S." surname="Jiang">
<organization>Huawei Technologies Co., Ltd</organization>
<address>
<postal>
<street>Q14, Huawei Campus, No.156 Beiqing Road</street>
<city>Hai-Dian District, Beijing, 100095</city>
<country>CN</country>
</postal>
<email>jiangsheng@huawei.com</email>
</address>
</author>
<author fullname="Lishan Li" initials="L." surname="Li">
<organization>Tsinghua University</organization>
<address>
<postal>
<street></street>
<city>Beijing</city>
<code>100084</code>
<country>P.R.China</country>
</postal>
<phone>+86-15201441862</phone>
<email>lilishan48@gmail.com</email>
</address>
</author>
<author fullname="Yong Cui" initials="Y." surname="Cui">
<organization>Tsinghua University</organization>
<address>
<postal>
<street></street>
<city>Beijing</city>
<code>100084</code>
<country>P.R.China</country>
</postal>
<phone>+86-10-6260-3059</phone>
<email>yong@csnet1.cs.tsinghua.edu.cn</email>
</address>
</author>
<author fullname="Tatuya Jinmei" initials="T." surname="Jinmei">
<organization>Infoblox Inc.</organization>
<address>
<postal>
<street>3111 Coronado Drive</street>
<city>Santa Clara</city>
<region>CA</region>
<country>US</country>
</postal>
<email>jinmei@wide.ad.jp</email>
</address>
</author>
<author fullname="Ted Lemon" initials="T." surname="Lemon">
<organization>Nominum, Inc.</organization>
<address>
<postal>
<street>2000 Seaport Blvd</street>
<city>Redwood City, CA</city>
<code>94063</code>
<country>USA</country>
</postal>
<phone>+1-650-381-6000</phone>
<email>Ted.Lemon@nominum.com</email>
</address>
</author>
<author fullname="Dacheng Zhang" initials="D." surname="Zhang">
<address>
<postal>
<street></street>
<city>Beijing</city>
<country>CN</country>
</postal>
<email>dacheng.zhang@gmail.com</email>
</address>
</author>
<date month="" year="2016" />
<area>Internet Area</area>
<workgroup>DHC Working Group</workgroup>
<keyword>Secure</keyword>
<keyword>DHCPv6</keyword>
<keyword>Public Key</keyword>
<abstract>
<t>DHCPv6 includes no deployable security mechanism that can protect
end-to-end communication between DHCP clients and servers. This
memo describes a mechanism for using public key cryptography to
provide such security. The mechanism provides encryption in all
cases, and can be used for authentication based either on pre-sharing
of authorized certificates, or else using trust-on-first-use.</t>
</abstract>
</front>
<middle>
<section title="Introduction">
<t>The Dynamic Host Configuration Protocol for IPv6 (DHCPv6, <xref
target="RFC3315"></xref>) allows DHCPv6 servers to flexibly provide
addressing and other configuration information relating to local
network infrastructure to DHCP clients. The protocol provides no
deployable security mechanism, and consequently is vulnerable to
various attacks.</t>
<t>This document provides a brief summary of the security vulnerabilities
of the DHCPv6 protocol and then describes a new extension to the
protocol that provides two additional types of security:<list style="symbols">
<t>authentication of the DHCPv6 client and the DHCPv6 server to
defend against active attacks, such as spoofing.</t>
<t>encryption between the DHCPv6 client and the DHCPv6 server in
order to protect the DHCPv6 from pervasive monitoring.</t>
</list></t>
<t>The extension specified in this document applies only to end-to-end
communication between DHCP servers and clients. Options added by
relay agents in Relay-Forward messages, and options other than
the client message in Relay-Reply messages sent by DHCP servers,
are not protected. Such communications are already protected
using the mechanism described described in section 21.1 in
<xref target="RFC3315"></xref>.</t>
<t>This extension introduces two new DHCPv6 messages: the Encrypted-
Query and the Encrypted-Response messages. It defines four
new DHCPv6 options: the Certificate, the Signature,
the Increasing-number, and the Encrypted-message options.
The Certificate, Signature, and Increasing-number options
are used for authentication. The Encryption-Query message,
Encryption-Response message and Encrypted-message option are used
for encryption.</t>
<!--
<t>The security mechanism specified in this document is based on DHCPv6
client/server's certificates with associated private keys. It also
integrates message signatures for the integrity
and timestamps for anti-replay. The sender authentication procedure
using certificates defined in this document depends on deployed Public
Key Infrastructure (PKI, <xref target="RFC5280"></xref>). However, the
deployment of PKI is out of the scope of this document.</t>
-->
</section>
<section title="Requirements Language and Terminology">
<t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in <xref
target="RFC2119"></xref> when they appear in ALL CAPS. When these words
are not in ALL CAPS (such as "should" or "Should"), they have their
usual English meanings, and are not to be interpreted as <xref
target="RFC2119"></xref> key words.</t>
</section>
<section title="Terminology">
<t>This section defines terminology specific to secure DHCPv6 used in
this document.</t>
<t><list hangIndent="16" style="hanging">
<t hangText="secure DHCPv6 client:">A node that initiates a DHCPv6 request on a
link to obtain DHCPv6 configuration parameters
from one or more DHCPv6 servers using the
encryption and optional authentication mechanisms
defined in this document.</t>
<t hangText="secure DHCPv6 server:">A DHCPv6 server that implements
the authentication and encryption mechanisms
defined in this document, and is configured
to use them.</t>
</list></t>
</section>
<section title="Security Issues of DHCPv6">
<t><xref target="RFC3315"></xref> defines an authentication mechanism
with integrity protection. This mechanism uses a symmetric key that is
shared by the client and server for authentication. It does not provide
any key distribution mechanism.</t>
<t>For this approach, operators can set up a key database for both
servers and clients from which the client obtains a key before
running DHCPv6. However, manual key distribution runs counter to
the goal of minimizing the configuration data needed at each host.
Consequently, there are no known deployments of this security
mechanism.</t>
<t><xref target="RFC3315"></xref> provides an additional mechanism for
preventing off-network timing attacks using the Reconfigure message:
the Reconfigure Key authentication method. However, this method protects
only the Reconfigure message. The key is transmitted in plaintext to
the client in earlier exchanges and so this method is vulnerable to
on-path active attacks.</t>
<t>Anonymity Profile for DHCP Clients <xref target="RFC7844"></xref>
explains how to generate DHCPv4 or DHCPv6 requests that minimize the
disclosure of identifying information. However, the anonymity profile
limits the use of the certain options. It also cannot anticipate
new options that may contain private information is defined. In
addition, the anonymity profile does not work in cases where
the client wants to maintain anonymity from eavesdroppers
but must identify itself to the DHCP server with which it
intends to communicate.</t>
<t>Privacy consideration for DHCPv6 <xref target="RFC7824"></xref>
presents an analysis of the privacy issues associated with the use
of DHCPv6 by Internet users. No solutions are presented.</t>
<t>Current DHCPv6 messages are still transmitted in cleartext and the
privacy information within the DHCPv6 message is not protected from
passive attack, such as pervasive monitoring <xref target="RFC7258"></xref>.
</t>
<t>To better address the problem of passive monitoring and to
achieve authentication without requiring a symmetric key
distribution solution for DHCP, this document defines an
asymmetric key authentication and encryption mechanism.
This protects against both active attacks, such as spoofing,
and passive attacks, such as pervasive monitoring.</t>
</section>
<section title="Secure DHCPv6 Overview">
<section title="Solution Overview">
<t>The following figure illustrated secure DHCPv6 procedure.
Briefly, this extension establishes the server's identity with an
anonymous Information-Request exchange. Once the server's identity
has been established, the client may either choose to communicate
with the server or not. Not communicating with an unknown server
avoids revealing private information, but if there is no known
server on a particular link, the client will be unable to communicate
with a DHCP server.</t>
<t>If the client chooses to communicate with a server, it uses the
Encrypted-Query message to encapsulate its communications to the
DHCP server. The server responds with Encrypted-Response messages.
Normal DHCP messages are encapsulated in these two new messages
using the new defined Encrypted-message option. Besides the
Encrypted-message option, the Signature option is defined to verify
the integrity of the DHCPv6 messages and then authentication of
client and server. The Increasing number is defined to detect
replay attack.</t>
<figure align="center" title="Secure DHCPv6 Procedure">
<artwork><![CDATA[
+-------------+ +-------------+
|DHCPv6 Client| |DHCPv6 Server|
+-------------+ +-------------+
| Information-request |
|----------------------------------------->|
| Option Request option |
| |
| Reply |
|<-----------------------------------------|
| Certificate option |
| Signature option |
| Increasing-number option |
| Server Identifier option |
| |
| Encryption-Query |
|----------------------------------------->|
| Encrypted-message option |
| Server Identifier option |
| |
| Encryption-Response |
|<-----------------------------------------|
| Encrypted-message option |
| |
]]></artwork>
</figure>
<!--
<t>It is worth noticing that the signature on a Secure DHCPv6 message
can be expected to significantly increase the size of the message. One
example is normal DHCPv6 message length plus 1 KB for a X.509
certificate and signature and 256 byte for a signature. IPv6 fragments
<xref target="RFC2460"></xref> are highly possible. Hence, deployment of
Secure DHCPv6 should also consider the issues of IP fragment, PMTU,
etc. Also, if there are firewalls and relays between secure DHCPv6 clients
and secure DHCPv6 servers, it is RECOMMENDED that the firewalls and
relays are configured to pass ICMP Packet Too Big messages <xref target="RFC4443"></xref>.</t>
-->
</section>
<section title="New Components">
<t>The new components of the mechanism specified in this document are
as follows:</t>
<t><list style="symbols">
<t>Servers and clients that use certificates first generate a
public/private key pair and then obtain a certificate that signs
the public key. The Certificate option is defined to carry the
certificate of the sender.</t>
<t>A signature generated using the private key which is used by the
receiver to verify the integrity of the DHCPv6 messages and then
authentication of the client/server. The Signature option is defined
to carry the signature.</t>
<t>A Increasing-number that can be used to detect replayed packet. The
Increasing-number option is defined to carry a strictly-increasing
serial number. Timestamp is one of the possible implementation choice.</t>
<t>The Encrypted-message option that contains the encrypted DHCPv6
message.</t>
<t>The Encrypted-Query message that is sent from the secure DHCPv6
client to the secure DHCPv6 server. The Encrypted-Query message
MUST contain the Encrypted-message option. In addition, the Server
Identifier option MUST be contained if it is contained in the
original DHCPv6 message. The Encrypted-Query message MUST NOT
contain other options except the Server Identifier option and
Encrypted-message option.</t>
<t>The Encrypted-Response message that is sent from the secure DHCPv6
server to the secure DHCPv6 client. The Encrypted-Response message
contains the Encrypted-message option. The Encrypted-Response message
MUST NOT contain other options except Encrypted-message option.</t>
</list></t>
</section>
<section title="Support for Algorithm Agility">
<t>In order to provide a means of addressing problems that may emerge
with existing hash algorithms, signature algorithm and encryption
algorithms in the future, this document provides a mechanism
to support algotirhm agility. The support for algorithm agility
in this document is mainly a algorithm notification mechanism between
the client and the server. The same client and server SHOULD use
the various algorithm in a single communication session.</t>
<!--
In some scenario, the hash and signature
algorithms cannot be separated, with e.g. eddsa that goes away as
the hash is fixed for the curve. In this scenario, the signature
algorithm field is set to the corresponding value and the hash
algorithm field is set to zero.</t>
-->
<t>If the server does not support the algorithm used by the client,
the server SHOULD reply with an AlgorithmNotSupported status code
(defined in <xref target="StatusCodes"></xref>) to the client.
Upon receiving this status code, the client MAY resend the message
protected with the mandatory algorithm.</t>
</section>
<!--
<section title="Support for Algorithm Agility">
<t>Hash functions are used to provide message integrity checks. In
order to provide a means of addressing problems that may emerge in the
future with existing hash algorithms, as recommended in <xref
target="RFC4270"></xref>, this document provides a mechanism for
negotiating the use of more secure hashes in the future.</t>
<t>In addition to hash algorithm agility, this document also provides
a mechanism for signature algorithm agility.</t>
<t>The support for algorithm agility in this document is a unilateral
notification mechanism from a server to a client through the Reply
message. A client MAY support various algorithms among different servers
simultaneously. It is NOT RECOMMENDED that the same client and server use
various algorithms in a single communication session.</t>
<t>If the client does not support the hash and signature algorithms used by
the server, the Reply message SHOULD be dropped. If both hash and signature
algorithms are supported, the client then checks the authority of this
server. The client SHOULD also use the same algorithms in the subsequent
messages.</t>
depending on the local policy on the client, the client can choose
to drop the message, or skip the check;
</section>
<section title="Imposed Additional Constraints">
<t>The client/server that supports identity verification MAY
impose additional constraints for verification. For example, it
may impose limits on minimum and maximum key lengths.</t>
<t><list style="hanging">
<t hangText="Minbits">The minimum acceptable key length for public
keys. An upper limit MAY also be set for the amount of computation
needed when verifying packets that use these security
associations. The appropriate lengths SHOULD be set according to
the signature algorithm and also following prudent cryptographic
practice. For example, minimum length 1024 and upper limit 2048
may be used for RSA <xref target="RSA"></xref>.</t>
</list></t>
</section>
-->
<section title="Applicability">
<t>In principle, secure DHCPv6 is applicable in any environment where
physical security on the link is not assured and attacks on DHCPv6
are a concern. In practice, however, authenticated and encrypted
DHCPv6 configuration will rely on some operational assumptions mainly
regarding public key distribution and management. In order to achieve
the more wide use of secure DHCPv6, opportunistic security <xref target="RFC7435"></xref>
can be applied for secure DHCPv6 deployment, which allows DHCPv6
encryption in environments where support for authentication is not
available.</t>
<t>In some scenario where authentication is not available, secure
DHCPv6 provides encryption without authentication to achieve the
wide deployment of secure DHCPv6.</t>
<t>Secure DHCPv6 provides authentication and encryption based either
on pre-sharing of authorized certificates, or else using trust-on-first-use.
The One feasible environment in an early deployment stage would be
enterprise networks. In such networks the security policy tends to
be strict and it will be easier to manage client hosts. One
trivial deployment scenario is therefore to manually pre-configure
client with the trusted servers' public key and manually register
clients' public keys for the server. It may also be possible to
deploy an internal PKI to make this less reliant on manual
operations, although it is currently subject to future study
specifically how to integrate such a PKI into the DHCPv6 service
for the network.</t>
<t>Note that this deployment scenario based on manual operation is not
different very much from the existing, shared-secret based
authentication mechanisms defined in <xref target="RFC3315"></xref> in
terms of operational costs. However, Secure DHCPv6 is still securer than
the shared-secret mechanism in that even if clients' keys stored
for the server are stolen that does not mean an immediate threat as
these are public keys. In addition, if some kind of PKI is used
with Secure DHCPv6, even if the initial installation of the
certificates is done manually, it will help reduce operational
costs of revocation in case a private key (especially that of the
server) is compromised.</t>
<t>It is believed that Secure DHCPv6 could be more widely applicable
with integration of generic PKI so that it will be more easily
deployed. But such a deployment requires more general issues with
PKI deployment be addressed, and it is currently unknown whether we
can find practical deployment scenarios. It is subject to future
study and experiments, and out of scope of this document.</t>
</section>
</section>
<section title="DHCPv6 Client Behavior">
<t>For the secure DHCPv6 client, a certificate is needed for client
authentication. The client is pre-configured with a certificate and its
corresponding private key. If the client is pre-configured with public
key but not with a certificate, it can generate the self-signed
certificate for client authentication.</t>
<t>The secure DHCPv6 client sends Information-request message as per
<xref target="RFC3315"></xref>. The Information-request message is used
by the DHCPv6 client to request the server's identity verification information
without having addresses, prefixes or any non-security options assigned to
it. The Information-request message MUST NOT include any DHCPv6 options
except ORO option to minimize client's privacy information leakage. The
Option Request option in the Information-request message MUST contain the
option code of the Certificate option.</t>
<t>When receiving the Reply messages from DHCPv6 servers, a secure
DHCPv6 client discards any DHCPv6 messages that meet any of the
following conditions:<list style="symbols">
<t>the Signature option is missing,</t>
<t>multiple Signature options are present,</t>
<t>the Certificate option is missing.</t>
</list></t>
<t>And then the client first checks the support of the hash algorithm,
signature algorithm and encryption algorithm that the server used. If
the check fails, the Reply message is dropped. If the hash algorithm
field is zero, the signature algorithm and hash algorithm are not
separated. The corresponding hash algorithm is fixed according the
signature algorithm. If all the algorithms are supported, the client
then checks the authority of this server. The client also uses the
same algorithms in the return messages.</t>
<t>The client validates the certificates through the pre-configured local
trusted certificates list or other methods. A certificate that finds a
match in the local trust certificates list is treated as verified.
<!--If the
client want to check server's certificate to see whether it has been revoked,
the OCSP stapling can be used.
-->
The message transaction-id is used as the identifier of the authenticated
server's public key for further message encryption. At this point, the
client has either recognized the certificate of the server, or decided
to drop the message.
</t>
<t>The client MUST now authenticate the server by verifying the signature
and checking increasing number, if there is a Increasing-number option.
The order of two procedures is left as an implementation decision. It is
RECOMMENDED to check increasing number first, because signature verification
is much more computationally expensive. If the decrypted message contains
the Increasing-number option, the client checks it by comparing it with
the stored number on the client. The client has one stable stored number
for replay attack detection. The initial value of the stable stored number
is zero. If the contained number is higher than the stored number, then
the DHCPv6 message passes the increasing-number check and the value of
the stored number is changed into the value of the Increasing-number
option. If contained number is lower than the stored number on the
server, the server MUST drop the DHCPv6 message.</t>
<t>The Signature field verification MUST show that the signature has
been calculated as specified in <xref target="SigOption"></xref>. Only
the messages that get through both the signature verification and
increasing number check (if there is a Increasing-number option) are
accepted. Reply message that does not pass the above tests MUST be
discarded.</t>
<t>If there are multiple authenticated DHCPv6 certs, the client
selects one DHCPv6 cert for the following network parameters
configuration. The selected DHCPv6 cert may corresponds to multiple
DHCPv6 servers. The client can also choose other implementation
method depending on the client's local policy if the defined protocol
can also run normally. For example, the client can try multiple
transactions (each encrypted with different public key) at the "same"
time.</t>
<t>If there are no authenticated DHCPv6 certs or existing servers
fail authentication, the client should retry a number of times. The
client conducts the server discovery process as per section 18.1.5
of <xref target="RFC3315"></xref> to avoid the packet storm. In this way,
it is difficult for the rogue server to beat out a busy "real" server.
And then the client takes some alternative action depending on its
local policy, such as attempting to use an unsecured DHCPv6 server.
In some scenario, such as laptops in coffee room, clients are always
not pre-configured the sufficient information for server authentication
and can accept DHCPv6 encryption without DHCPv6 authentication. In
such scenario, if some DHCPv6 servers fail authentication because
the server's certificate is not in the trusted certs' list, and
then the client selects one DHCPv6 server and record the server's
public key for the future encrypted DHCPv6 configuration process.</t>
<t>Once the server has been authenticated, the DHCPv6 client sends the
Encrypted-Query message to the DHCPv6 server. The Encrypted-Query message
contains the Encrypted-message option, which MUST be constructed as
explained in <xref target="EncryMesOption"></xref>. In addition, the Server
Identifier option MUST be contained if it is in the original message
(i.e. Request, Renew, Decline, Release) to avoid the extra decryption
for the DHCPv6 servers not for it. The Encrypted-message option contains
the DHCPv6 message that is encrypted using the public key contained in
the selected cert. The Server Identifier option is externally visible to
avoid decryption cost by those unselected servers. The Encrypted-Query
message MUST NOT contain other DHCPv6 option except the Server Identifier
option and Encrypted-Message option.</t>
<t>If the received Reply message indicates the request of the client's
certificate information through the Option Request option, the first
DHCPv6 message sent from the client to the server, such as Solicit
message, MUST contain the Certificate option, Signature option and
Increasing-number option for client authentication. The encryption
text SHOULD be formatted as explain in <xref target="RFC5652"></xref>. The Certificate option MUST be constructed as explained in <xref target="CertOption"></xref>. In addition, one and only one Signature option MUST be contained,
which MUST be constructed as explained in <xref target="SigOption"></xref>.
One and only one Increasing-number option SHOULD be contained, which
MUST be constructed as explained in <xref target="IncreasingNumOption"></xref>.</t>
<t>If the client has multiple certificates with different public/private
key pairs, the message transaction-id is used as the identifier of the
client's private key for decryption. In addition, the subsequent encrypted
DHCPv6 message can contain the Increasing-number option to defend against
replay attack.</t>
<t>For the received Encrypted-Response message, the client MUST drop the
Encrypted-Response message if other DHCPv6 option except Encrypted-message
option is contained. Then, the client extracts the Encrypted-message
option and decrypts it using its private key to obtain the original DHCPv6
message. Then it handles the message as per <xref target="RFC3315"></xref>.
If the decrypted DHCPv6 message contains the Increasing-number option, the
DHCPv6 client MUST drop the DHCPv6 message with the lower number. If the
client fails to get the proper parameters from the chosen server, it sends
the Encrypted-Query message to another authenticated server for parameters
configuration until the client obtains the proper parameters.</t>
<t>When the client receives a Reply message with an error status code,
the error status code indicates the failure reason on the server side.
According to the received status code, the client MAY take follow-up
action:</t>
<t><list style="symbols">
<t>Upon receiving an AlgorithmNotSupported error status code, the
client SHOULD resend the message protected with one of the
mandatory algorithms.</t>
<t>Upon receiving an AuthenticationFail error status code, the
client is not able to build up the secure communication with the
server. However, there may be other DHCPv6 servers available that
successfully complete authentication. The client MAY use the
AuthenticationFail as a hint and switch to other certificate if
it has another one; but otherwise treat the message containing the
status code as if it had not been received. But it SHOULD NOT retry
with the same certificate. However, if the client decides to retransmit
using the same certificate after receiving AuthenticationFail, it MUST
NOT retransmit immediately and MUST follow normal retransmission
routines defined in <xref target="RFC3315"></xref>.</t>
<t>Upon receiving a DecryptionFail error status code, the client MAY
resend the message following normal retransmission routines
defined in <xref target="RFC3315"></xref>.</t>
<t>Upon receiving a IncreasingnumFail error status code, the client
MAY resend the message with an adjusted Increasing-number option
according to the returned clock from the DHCPv6 server.</t>
<t>Upon receiving a SignatureFail error status code, the client MAY
resend the message following normal retransmission routines defined
in <xref target="RFC3315"></xref>.</t>
</list></t>
</section>
<section title="DHCPv6 Server Behavior">
<t>For the secure DHCPv6 server, a certificate is needed for server
authentication. The server is pre-configured with a certificate and its
corresponding private key. If the server is pre-configured with public
key but not with a certificate, it can generate the self-signed certificate
for server authentication.</t>
<t>When the DHCPv6 server receives the Information-request message and
the contained Option Request option identifies the request is for the server
certificate information, it replies with a Reply message to the client.
The Reply message MUST contain the requested Certificate option, which
MUST be constructed as explained in <xref target="CertOption"></xref>,
and Server Identifier option. In addition, the Reply message MUST contain
one and only one Signature option, which MUST be constructed as explained
in <xref target="SigOption"></xref>. Besides, the Reply message SHOULD
contain one and only one Increasing-number option, which MUST be constructed
as explained in <xref target="IncreasingNumOption"></xref>. In addition,
if client authentication is needed, then the ORO option in the Reply
message contains the code of the certificate option to indicate the
request of the client certificate information.</t>
<t>Upon the receipt of Encrypted-Query message, the server MUST drop
the message if the other DHCPv6 option except Server Identifier option
and Encrypted-message option is contained. Then, the server checks the
Server Identifier option if the Encrypted-Query message contains the
Server Identifier option. The DHCPv6 server drops the message that is
not for it, thus not paying cost to decrypt messages not for it. It
decrypts the Encrypted-message option using its private key if it is
the target server. </t>
<t>If the secure DHPCv6 need client authentication and decrypted message
is a Solicit/Information-request message which contains the information
for client authentication, the secure DHCPv6 server discards the received
message that meets any of the following conditions:<list style="symbols">
<t>the Signature option is missing,</t>
<t>multiple Signature options are present,</t>
<t>the Certificate option is missing.</t>
</list></t>
<t>In such failure, the server replies with an UnspecFail (value 1,
<xref target="RFC3315"></xref>) error status code.</t>
<t>The server SHOULD first check the support of the hash function,
signature algorithm, encryption algorithm that the client used. If
the hash algorithm field is zero, then the signature algorithm and
hash algorithm are not separated. The corresponding hash algorithm
is fixed according the signature algorithm. If the check fails, the
server SHOULD reply with an AlgorithmNotSupported error status code,
defined in <xref target="StatusCodes"></xref>, back to the client.
If all the algorithms are supported, the server then checks the
authority of this client.</t>
<t>The server validates the client's certificate through the local
pre-configured trusted certificates list. A certificate that finds
a match in the local trust certificates list is treated as verified.
The message that fails authentication validation MUST be dropped.
In such failure, the DHCPv6 server replies with an AuthenticationFail
error status code, defined in <xref target="StatusCodes"></xref>,
back to the client. At this point, the server has either recognized
the authentication of the client, or decided to drop the message.</t>
<t>If the decrypted message contains the Increasing-number option, the
server checks it by comparing it with the stored number on the server.
The server has one stable stored number for replay attack detection. The
initial value of the stable stored number is zero. If the contained number
is higher than the stored number, the value of the stored number is
changed into the value of the Increasing-number option. If contained
number is lower than the stored number on the server, the server MUST
drop the DHCPv6 message and a IncreasingnumFail error status code,
defined in <xref target="StatusCodes"></xref>, should be sent back to
the client. Depending on server's local policy, the message without a
Increasing-number option MAY be acceptable or rejected. If the server
rejects such a message, a IncreasingnumFail error status code should
be sent back to the client. The Reply message that carries the
IncreasingnumFail error status code carries a Increasing-number option,
which indicates the server's storage number for the client to use.</t>
<!--
<t>If the server does not send the Timestamp option, the client ignores
the timestamp check and verifies the signature. If there is a timestamp
option, the server MUST now authenticate the client by verifying the
signature and checking timestamp (see details in <xref
target="timestampCheck"></xref>). The order of two procedures is left as
an implementation decision. It is RECOMMENDED to check timestamp first,
because signature verification is much more computationally expensive.
Depending on server's local policy, the message without a Timestamp
option MAY be acceptable or rejected. If the server rejects such a
message, a TimestampFail error status code, defined in <xref
target="StatusCodes"></xref>, should be sent back to the client. The
reply message that carries the TimestampFail error status code SHOULD
carry a Timestamp option, which indicates the server's clock for the
client to use.</t>
-->
<t>The Signature field verification MUST show that the signature has
been calculated as specified in <xref target="SigOption"></xref>. Only
the clients that get through both the signature verification and
increasing number check (if there is a Increasing-number option) are
accepted as authenticated clients and continue to be handled their message as
defined in <xref target="RFC3315"></xref>. Clients that do not pass the
above tests MUST be treated as unauthenticated clients. The DHCPv6
server SHOULD reply a SignatureFail error status code, defined in <xref
target="StatusCodes"></xref>, for the signature verification failure.</t>
<!--
; or
a TimestampFail error status code, defined in <xref
target="StatusCodes"></xref>, for the timestamp check failure, back to
the client.
-->
<t>Once the client has been authenticated, the DHCPv6 server sends the
Encrypted-response message to the DHCPv6 client. The Encrypted-response
message MUST only contain the Encrypted-message option, which MUST be
constructed as explained in <xref target="EncryMesOption"></xref>. The
encryption text SHOULD be formatted as explain in <xref target="RFC5652"></xref>.
The Encrypted-message option contains the encrypted DHCPv6 message that
is encrypted using the authenticated client's public key. To provide the
replay protection, the Increasing-number option can be contained in the
encrypted DHCPv6 message.</t>
</section>
<section title="Relay Agent Behavior">
<t>When a DHCPv6 relay agent receives an Encrypted-query or
Encrypted-response message, it may not recognize this message. The
unknown messages MUST be forwarded as described in <xref
target="RFC7283"></xref>.</t>
<t>When a DHCPv6 relay agent recognizes the Encrypted-query and
Encrypted-response messages, it forwards the message according to
section 20 of <xref target="RFC3315"></xref>. There is nothing more the
relay agents have to do, it neither needs to verify the messages from
client or server, nor add any secure DHCPv6 options. Actually, by
definition in this document, relay agents MUST NOT add any secure
DHCPv6 options.</t>
<t>Relay-forward and Relay-reply messages MUST NOT contain any
additional Certificate option or Increasing-number option, aside from those
present in the innermost encapsulated messages from the client or
server.</t>
<t>Relay agent is RECOMMENDED to cache server announcements to form
the list of the available DHCPv6 server certs. If the relay agent
receives the Information-request message, then it replies with
a list of server certs available locally. In this way, the client
can be confident of a quick response, and therefore treat the lack
of a quick response as an indication that no authenticated DHCP servers
exist.</t>
</section>
<!--
<section title="Processing Rules">
<section anchor="timestampCheck" title="Timestamp Check">
<t>In order to check the Timestamp option, defined in <xref
target="TimeStampOption"></xref>, recipients SHOULD be configured with
an allowed timestamp Delta value, a "fuzz factor" for comparisons, and
an allowed clock drift parameter. The recommended default value for
the allowed Delta is 300 seconds (5 minutes); for fuzz factor 1
second; and for clock drift, 0.01 second.</t>
<t>Note: the Timestamp mechanism is based on the assumption that
communication peers have roughly synchronized clocks, within certain
allowed clock drift. So, an accurate clock is not necessary. If one has a
clock too far from the current time, the timestamp mechanism would not
work.</t>
<t>To facilitate timestamp checking, each recipient SHOULD store the
following information for each sender, from which at least one
accepted secure DHCPv6 message is successfully verified (for
timestamp check and signature verification):</t>
<t><list style="symbols">
<t>The receive time of the last received and accepted DHCPv6
message. This is called RDlast.</t>
<t>The timestamp in the last received and accepted DHCPv6 message.
This is called TSlast.</t>
</list>A verified (for timestamp check and signature verification)
secure DHCPv6 message initiates the update of the above variables
in the recipient's record.</t>
<t>Recipients MUST check the Timestamp field as follows:</t>
<t><list style="symbols">
<t>When a message is received from a new peer (i.e., one that is
not stored in the cache), the received timestamp, TSnew, is
checked, and the message is accepted if the timestamp is recent
enough to the reception time of the packet, RDnew:<list
style="empty">
<t>-Delta < (RDnew - TSnew) < +Delta</t>
</list><vspace blankLines="1" />After the signature verification
also succeeds, the RDnew and TSnew values SHOULD be stored in the
cache as RDlast and TSlast.</t>
<t>When a message is received from a known peer (i.e., one that
already has an entry in the cache), the timestamp is checked
against the previously received Secure DHCPv6 message:<list
style="empty">
<t>TSnew + fuzz > TSlast + (RDnew - RDlast) x (1 - drift) -
fuzz</t>
</list><vspace blankLines="1" />If this inequality does not hold
or RDnew < RDlast, the recipient SHOULD silently discard the
message. If, on the other hand, the inequality holds, the
recipient SHOULD process the message. <vspace
blankLines="1" />Moreover, if the above inequality holds and TSnew
> TSlast, the recipient SHOULD update RDlast and TSlast after
the signature verification also successes. Otherwise, the
recipient MUST NOT update RDlast or TSlast.</t>
</list>An implementation MAY use some mechanism such as a timestamp
cache to strengthen resistance to replay attacks. When there is a very
large number of nodes on the same link, or when a cache filling attack
is in progress, it is possible that the cache holding the most recent
timestamp per sender will become full. In this case, the node MUST
remove some entries from the cache or refuse some new requested
entries. The specific policy as to which entries are preferred over
others is left as an implementation decision.</t>
<t>An implementation MAY statefully record the latest timestamps from
senders. In such implementation, the timestamps MUST be strictly
monotonously increasing. This is reasonable given that DHCPv6 messages
are rarely misordered.</t>
</section>
</section>
-->
<section title="Extensions for Secure DHCPv6">
<t>This section describes the extensions to DHCPv6. Four new DHCPv6
options, two new DHCPv6 messages and five new status codes are
defined.</t>
<section title="New DHCPv6 Options">
<section anchor="CertOption" title="Certificate Option">
<t>The Certificate option carries the certificate of the client/server.
The format of the Certificate option is described as follows:</t>
<t><figure align="center">
<artwork><![CDATA[ 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_CERTIFICATE | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| EA-id | |
+-+-+-+-+-+-+-+-+ .
. Certificate (variable length) .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code OPTION_CERTIFICATE (TBA1).
option-len 1 + Length of certificate in octets.
EA-id Encryption Algorithm id. The encryption algorithm
is used for the encrypted DHCPv6 configuration
process. This design is adopted in order to provide
encryption algorithm agility. The value is from the
Encryption Algorithm for Secure DHCPv6 registry in
IANA. A registry of the initial assigned values
is defined in Section 12.
Certificate A variable-length field containing certificate. The
encoding of certificate and certificate data MUST
be in format as defined in Section 3.6, [RFC7296].
The support of X.509 certificate is mandatory.
]]></artwork>
</figure></t>
</section>
<section anchor="SigOption" title="Signature option">
<t>The Signature option allows a signature that is signed by the
private key to be attached to a DHCPv6 message. The Signature option
could be in any place within the DHCPv6 message while it is logically
created after the entire DHCPv6 header and options. It protects the
entire DHCPv6 header and options, including itself. The format of
the Signature option is described as follows:</t>
<t><figure align="center">
<artwork><![CDATA[ 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_SIGNATURE | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SA-id | HA-id | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
. Signature (variable length) .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code OPTION_SIGNATURE (TBA2).
option-len 2 + Length of Signature field in octets.
SA-id Signature Algorithm id. The signature algorithm is
used for computing the signature result. This
design is adopted in order to provide signature
algorithm agility. The value is from the Signature
Algorithm for Secure DHCPv6 registry in IANA. The
support of RSASSA-PKCS1-v1_5 is mandatory. A
registry of the initial assigned values is defined
in Section 12.
HA-id Hash Algorithm id. The hash algorithm is used for
computing the signature result. This design is
adopted in order to provide hash algorithm agility.
The value is from the Hash Algorithm for Secure
DHCPv6 registry in IANA. The support of SHA-256 is
mandatory. A registry of the initial assigned values
is defined in Section 12. If the signature algorithm
and hash algorithm cannot be separated, the HA-id
field is zero. The hash algorithm is decided by the
corresponding signature algorithm.
Signature A variable-length field containing a digital
signature. The signature value is computed with
the hash algorithm and the signature algorithm,
as described in HA-id and SA-id. The signature
constructed by using the sender's private key
protects the following sequence of octets:
1. The DHCPv6 message header.
2. All DHCPv6 options including the Signature
option (fill the Signature field with zeroes).
The Signature field MUST be padded, with all 0, to
the next octet boundary if its size is not a
multiple of 8 bits. The padding length depends on
the signature algorithm, which is indicated in the
SA-id field.
]]></artwork>
</figure></t>
<t>Note: If Secure DHCPv6 is used, the DHCPv6 message is encrypted in a
way that the authentication mechanism defined in RFC3315 does not understand.
So the Authentication option SHOULD NOT be used if Secure DHCPv6 is
applied.</t>
<!--Note: if both signature and authentication option are
present, Signature option does not protect the Authentication
Option. It allows the Authentication Option to be created after
signature has been calculated and filled with the valid signature.
It is because both options need to apply hash algorithm to whole
message, so there must be a clear order and there can be only one
last-created option. In order to avoid update <xref target="RFC3315"></xref>
because of changing auth option, the authors choose not to include
authentication option in the signature.</t>
-->
</section>
<section anchor="IncreasingNumOption" title="Increasing-number Option">
<t>The Increasing-number option carries the number which is higher than the
local stored number on the client/server. It adds the anti-replay protection
to the DHCPv6 messages. It is optional.</t>
<t><figure>
<artwork><![CDATA[ 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_INCREASINGNUM | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| InreasingNum (32-bit) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code OPTION_INCREASINGNUM (TBA3).
option-len 4, in octets.
IncreasingNum A number which is higher than the local stored number on the
client/server for the replay attack detection.
]]></artwork>
</figure></t>
</section>
<section anchor="EncryMesOption" title="Encrypted-message Option">
<t>The Encrypted-message option carries the encrypted DHCPv6 message
with the recipient's public key.</t>
<t>The format of the Encrypted-message option is:</t>
<figure align="center" anchor="option-dhcpv6-msg"
title="Encrypted-message Option Format">
<artwork><![CDATA[
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| option-code | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. encrypted DHCPv6 message .
. (variable) .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t><list style="hanging">
<t hangText="option-code">OPTION_ENCRYPTED_MSG (TBA4).</t>
<t hangText="option-len">Length of the encrypted DHCPv6
message.</t>
<t hangText="encrypted DHCPv6 message">A variable length field
containing the encrypted DHCPv6 message sent by the client or
the server. In Encrypted-Query message, it contains encrypted
DHCPv6 message sent by a client. In Encrypted-response message,
it contains encrypted DHCPv6 message sent by a server.</t>
</list></t>
</section>
</section>
<section anchor="DHCPv6Messages" title="New DHCPv6 Messages">
<t>Two new DHCPv6 messages are defined to achieve the DHCPv6 encryption:
Encrypted-Query and Encrypted-Response. Both the DHCPv6 messages defined
in this document share the following format:</t>
<figure align="center" anchor="encrypted-query-format"
title="The format of Encrypted-Query and Encrypted-Response Messages">
<artwork><![CDATA[
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| msg-type | transaction-id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. options .
. (variable) .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t><list hangIndent="16" style="hanging">
<t hangText="msg-type">Identifier of the message type. It can be either
Encrypted-Query (TBA5) or DHCPv6-Response (TBA6).</t>
<t hangText="transaction-id">The transaction ID for this message
exchange.</t>
<t hangText="options">The Encrypted-Query message MUST only contain
the Server Identifier option or Encrypted-message option. The
Encrypted-Response message MUST only contain the Encrypted-message
option.</t>
</list></t>
</section>
<section anchor="StatusCodes" title="Status Codes">
<t>The following new status codes, see Section 5.4 of <xref
target="RFC3315"></xref> are defined. <list style="symbols">
<t>AlgorithmNotSupported (TBD7): indicates that the DHCPv6 server
does not support algorithms that sender used.</t>
<t>AuthenticationFail (TBD8): indicates that the message from the
DHCPv6 client fails authentication check.</t>
<t>IncreasingnumFail (TBD9): indicates the message from DHCPv6 client
fails the increasing number check.</t>
<t>SignatureFail (TBD10): indicates the message from DHCPv6 client
fails the signature check.</t>
<t>DecryptionFail (TBD11): indicates the message from DHCPv6 client
fails the DHCPv6 message decryption.</t>
</list></t>
</section>
</section>
<section anchor="Security" title="Security Considerations">
<t>This document provides the authentication and encryption mechanisms
for DHCPv6.</t>
<t><xref target="RFC6273"></xref> has analyzed possible threats to the
hash algorithms used in SEND. Since Secure DHCPv6 defined in this
document uses the same hash algorithms in similar way to SEND, analysis
results could be applied as well: current attacks on hash functions do
not constitute any practical threat to the digital signatures used in
the signature algorithm in Secure DHCPv6.</t>
<t>A server, whose local policy accepts messages without a Increasing-number
option, may have to face the risk of replay attacks.</t>
<!--
<t>A window of vulnerability for replay attacks exists until the
timestamp expires. Secure DHCPv6 nodes are protected against replay
attacks as long as they cache the state created by the message
containing the timestamp. The cached state allows the node to protect
itself against replayed messages. However, once the node flushes the
state for whatever reason, an attacker can re-create the state by
replaying an old message while the timestamp is still valid. In
addition, the effectiveness of timestamps is largely dependent upon the
accuracy of synchronization between communicating nodes. However, how
the two communicating nodes can be synchronized is out of scope of this
work.</t>
-->
<!--
<t>Attacks against time synchronization protocols such as NTP <xref target="RFC5905"></xref>
may cause Secure DHCPv6 nodes to have an incorrect timestamp value. This
can be used to launch replay attacks, even outside the normal window of
vulnerability. To protect against these attacks, it is recommended that
Secure DHCPv6 nodes keep independently maintained clocks or apply
suitable security measures for the time synchronization protocols.</t>
-->
<t>There are some mandatory algorithm for encryption algorithm in this
document. It may be at some point that the mandatory algorithm is no
longer safe to use.</t>
<t>If the client tries more than one cert for client authentication, the
server can easily get a client that implements this to enumerate its
entire cert list and probably learn a lot about a client that way.</t>
</section>
<section anchor="IANA" title="IANA Considerations">
<t>This document defines four new DHCPv6 <xref target="RFC3315"></xref>
options. The IANA is requested to assign values for these four options
from the DHCPv6 Option Codes table of the DHCPv6 Parameters registry
maintained in http://www.iana.org/assignments/dhcpv6-parameters. The
four options are:</t>
<t><list style="empty">
<t>The Certificate Option (TBA1), described in <xref
target="CertOption"></xref>.</t>
<t>The Signature Option (TBA2), described in <xref
target="SigOption"></xref>.</t>
<t>The Increasing-number Option (TBA3),described in <xref
target="IncreasingNumOption"></xref>.</t>
<t>The Encrypted-message Option (TBA4), described in <xref
target="EncryMesOption"></xref>.</t>
</list></t>
<t>The IANA is also requested to assign value for these two messages
from the DHCPv6 Message Types table of the DHCPv6 Parameters registry
maintained in http://www.iana.org/assignments/dhcpv6-parameters. The two
messages are:</t>
<t><list style="empty">
<t>The Encrypted-Query Message (TBA5), described in <xref
target="DHCPv6Messages"></xref>.</t>
<t>The Encrypted-Response Message (TBA6), described in <xref
target="DHCPv6Messages"></xref>.</t>
</list></t>
<t>The IANA is also requested to add three new registry tables to the
DHCPv6 Parameters registry maintained in
http://www.iana.org/assignments/dhcpv6-parameters. The three tables are
the Hash Algorithm for Secure DHCPv6 table, the Signature Algorithm
for Secure DHCPv6 table and the Encryption Algorithm for Secure DHCPv6
table.</t>
<t>Initial values for these registries are given below. Future
assignments are to be made through Standards Action <xref
target="RFC5226"></xref>. Assignments for each registry consist of a
name, a value and a RFC number where the registry is defined.</t>
<t>Hash Algorithm for Secure DHCPv6. The values in this table are 8-bit
unsigned integers. The following initial values are assigned for Hash
Algorithm for Secure DHCPv6 in this document:</t>
<t><figure>
<artwork><![CDATA[ Name | Value | RFCs
-------------------+---------+--------------
SigAlg-Combined | ox00 | this document
SHA-256 | 0x01 | this document
SHA-512 | 0x02 | this document
]]></artwork>
</figure>Signature Algorithm for Secure DHCPv6. The values in this
table are 8-bit unsigned integers. The following initial values are
assigned for Signature Algorithm for Secure DHCPv6 in this document:</t>
<t><figure>
<artwork><![CDATA[ Name | Value | RFCs
-------------------+---------+--------------
RSASSA-PKCS1-v1_5 | 0x01 | this document
]]></artwork>
</figure>Encryption algorithm for Secure DHCPv6. The values in this table are
8-bit unsigned integers. The following initial values are assigned for
encryption algorithm for Secure DHCPv6 in this document:</t>
<t><figure>
<artwork><![CDATA[ Name | Value | RFCs
-------------------+---------+--------------
RSA | 0x01 | this document
]]></artwork>
</figure></t>
<t>IANA is requested to assign the following new DHCPv6 Status
Codes, defined in <xref target="StatusCodes"></xref>, in the DHCPv6
Parameters registry maintained in
http://www.iana.org/assignments/dhcpv6-parameters:</t>
<t><figure>
<artwork><![CDATA[ Code | Name | Reference
---------+-----------------------+--------------
TBD7 | AlgorithmNotSupported | this document
TBD8 | AuthenticationFail | this document
TBD9 | IncreasingnumFail | this document
TBD10 | SignatureFail | this document
TBD11 | DecryptionFail | this document
]]></artwork>
</figure></t>
</section>
<section anchor="Acknowledgments" title="Acknowledgements">
<t>The authors would like to thank Tomek Mrugalski, Bernie Volz, Jianping
Wu, Randy Bush, Yiu Lee, Sean Shen, Ralph Droms, Jari Arkko, Sean
Turner, Stephen Farrell, Christian Huitema, Stephen Kent, Thomas Huth,
David Schumacher, Francis Dupont, Gang Chen, Suresh Krishnan, Fred
Templin, Robert Elz, Nico Williams, Erik Kline, Alan DeKok, Bernard
Aboba, Sam Hartman, Qi Sun, Zilong Liu and other members of the IETF
DHC working group for their valuable comments.</t>
<t>This document was produced using the xml2rfc tool <xref
target="RFC2629"></xref>.</t>
</section>
<section anchor="changes" title="Change log [RFC Editor: Please remove]">
<t>draft-ietf-dhc-sedhcpv6-13: Change the Timestamp option into
Increasing-number option and the corresponding check method; Delete
the OCSP stampling part for the certificate check; Add the scenario
where the hash and signature algorithms cannot be separated; Add the
comparison with RFC7824 and RFC7844; Add the encryption text format
and reference of RFC5652. Add the consideration of scenario where
multiple DHCPv6 servers share one common DHCPv6 server. Add the
statement that Encrypted-Query and Encrypted-Response messages can
only contain certain options: Server Identifier option and
Encrypted-message option. Add opportunistic security for deployment
consideration. Besides authentication+encyrption mode, encryption-only
mode is added.</t>
<t>draft-ietf-dhc-sedhcpv6-12: Add the Signature option and timestamp
option during server/client authentication process. Add the hash
function and signature algorithm. Add the requirement: The Information-request
message cannot contain any other options except ORO option. Modify
the use of "SHOULD"; Delete the reference of RFC5280 and modify the
method of client/server cert verification; Add the relay agent cache
function for the quick response when there is no authenticated server.
2016-4-24.</t>
<t>draft-ietf-dhc-sedhcpv6-11: Delete the Signature option, because the
encrypted DHCPv6 message and the Information-request message (only contain
the Certificate option) don't need the Signature option for message
integrity check; Rewrite the "Applicability" section; Add the encryption
algorithm negotiation process; To support the encryption algorithm
negotiation, the Certificate option contains the EA-id(encryption
algorithm identifier) field; Reserve the Timestamp option to defend
against the replay attacks for encrypted DHCPv6 configuration process;
Modify the client behavior when there is no authenticated DHCPv6 server;
Add the DecryptionFail error code. 2016-3-9.</t>
<t>draft-ietf-dhc-sedhcpv6-10: merge DHCPv6 authentication and DHCPv6
encryption. The public key option is removed, because the device can
generate the self-signed certificate if it is pre-configured the public
key not the certificate. 2015-12-10.</t>
<t>draft-ietf-dhc-sedhcpv6-09: change some texts about the deployment
part.2015-12-10.</t>
<t>draft-ietf-dhc-sedhcpv6-08: clarified what the client and the server
should do if it receives a message using unsupported algorithm; refined
the error code treatment regarding to AuthenticationFail and
TimestampFail; added consideration on how to reduce the DoS attack when
using TOFU; other general editorial cleanups. 2015-06-10.</t>
<t>draft-ietf-dhc-sedhcpv6-07: removed the deployment consideration
section; instead, described more straightforward use cases with TOFU in
the overview section, and clarified how the public keys would be stored
at the recipient when TOFU is used. The overview section also clarified
the integration of PKI or other similar infrastructure is an open issue.
2015-03-23.</t>
<t>draft-ietf-dhc-sedhcpv6-06: remove the limitation that only clients
use PKI- certificates and only servers use public keys. The new text
would allow clients use public keys and servers use PKI-certificates.
2015-02-18.</t>
<t>draft-ietf-dhc-sedhcpv6-05: addressed comments from mail list that
responsed to the second WGLC. 2014-12-08.</t>
<t>draft-ietf-dhc-sedhcpv6-04: addressed comments from mail list. Making
timestamp an independent and optional option. Reduce the serverside
authentication to base on only client's certificate. Reduce the
clientside authentication to only Leaf of Faith base on server's public
key. 2014-09-26.</t>
<t>draft-ietf-dhc-sedhcpv6-03: addressed comments from WGLC. Added a new
section "Deployment Consideration". Corrected the Public Key Field in
the Public Key Option. Added consideration for large DHCPv6 message
transmission. Added TimestampFail error code. Refined the retransmission
rules on clients. 2014-06-18.</t>
<t>draft-ietf-dhc-sedhcpv6-02: addressed comments (applicability
statement, redesign the error codes and their logic) from IETF89 DHC WG
meeting and volunteer reviewers. 2014-04-14.</t>
<t>draft-ietf-dhc-sedhcpv6-01: addressed comments from IETF88 DHC WG
meeting. Moved Dacheng Zhang from acknowledgement to be co-author.
2014-02-14.</t>
<t>draft-ietf-dhc-sedhcpv6-00: adopted by DHC WG. 2013-11-19.</t>
<t>draft-jiang-dhc-sedhcpv6-02: removed protection between relay agent
and server due to complexity, following the comments from Ted Lemon,
Bernie Volz. 2013-10-16.</t>
<t>draft-jiang-dhc-sedhcpv6-01: update according to review comments from
Ted Lemon, Bernie Volz, Ralph Droms. Separated Public Key/Certificate
option into two options. Refined many detailed processes.
2013-10-08.</t>
<t>draft-jiang-dhc-sedhcpv6-00: original version, this draft is a
replacement of draft-ietf-dhc-secure-dhcpv6, which reached IESG and dead
because of consideration regarding to CGA. The authors followed the
suggestion from IESG making a general public key based mechanism.
2013-06-29.</t>
</section>
<section anchor="Issues" title="Open Issues [RFC Editor: Please remove]">
<t>The Reply message with the error status code may contain the client
identifier option, then the client's privacy information may be disclosed.
The possible way is that we encrypts the Reply message. But if the error
is AlogorithmNotSupported, then the server cannot encrypt the message with
the algorithm used by client.</t>
<t>We need to add some explanation on why TOFU is out of scope currently.
TOFU is tricky to get it right. If it is included, then operator may skip
necessary setup for security. TOFU may be included in the future work.</t>
</section>
</middle>
<back>
<references title="Normative References">
<?rfc include='reference.RFC.2119'?>
<?rfc include='reference.RFC.2460'?>
<?rfc include='reference.RFC.3315'?>
<?rfc include='reference.RFC.3971'?>
<?rfc include='reference.RFC.4443'?>
<?rfc include='reference.RFC.5652'?>
<?rfc include='reference.RFC.5905'?>
<?rfc include='reference.RFC.7296'?>
<?rfc include='reference.RFC.7283'?>
<?rfc include='reference.RFC.7435'?>
<?rfc include='reference.RFC.7824'?>
<?rfc include='reference.RFC.7844'?>
</references>
<references title="Informative References">
<reference anchor="RSA">
<front>
<title>RSA Encryption Standard, Version 2.1, PKCS 1</title>
<author fullname="">
<organization>RSA Laboratories</organization>
</author>
<date month="November" year="2002" />
</front>
</reference>
<?rfc include='reference.RFC.2629'?>
<?rfc include='reference.RFC.5226'?>
<?rfc include='reference.RFC.6273'?>
<?rfc include='reference.RFC.7258'?>
</references>
</back>
</rfc>
| PAFTECH AB 2003-2026 | 2026-04-23 16:42:18 |