Secure DHCPv6 with Public Key
draft-jiang-dhc-sedhcpv6-00

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Document Type Active Internet-Draft (individual)
Authors Sheng Jiang  , Sean Shen 
Last updated 2013-06-29
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DHC Working Group                                          Sheng Jiang 
Internet Draft                            Huawei Technologies Co., Ltd 
Intended status: Proposed Standard                           Sean Shen 
Update: RFC3315                                                  CNNIC 
Expires: December 31, 2013                               June 29, 2013 
                                    
                     Secure DHCPv6 with Public Key 
                    draft-jiang-dhc-sedhcpv6-00.txt 

Status of this Memo 

   This Internet-Draft is submitted to IETF in full conformance with the 
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   This Internet-Draft will expire on December 31, 2013. 

    

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Abstract 

   The Dynamic Host Configuration Protocol for IPv6 (DHCPv6) enables 
   DHCPv6 servers to pass configuration parameters. It offers 
   configuration flexibility. If not secured, DHCPv6 is vulnerable to 
   various attacks, particularly spoofing attacks. This document 
   analyzes the security issues of DHCPv6 and specifies a Secure DHCPv6 
   mechanism. This mechanism is based on public/private key pairs. The 
   authority of the sender may depend on either pre-configuration 
   mechanism or Public Key Infrastructure. 

    

Table of Contents 

   1. Introduction ................................................ 3 
   2. Terminology ................................................. 3 
   3. Security Overview of DHCPv6 ................................. 3 
   4. Secure DHCPv6 Overview ...................................... 4 
      4.1. New Components ......................................... 5 
      4.2. Support for algorithm agility .......................... 5 
   5. Extensions for Secure DHCPv6 ................................ 6 
      5.1. Key/Certificate Option ................................. 6 
      5.2. Signature Option ....................................... 6 
   6. Processing Rules and Behaviors .............................. 8 
      6.1. Processing Rules of Sender ............................. 8 
      6.2. Processing Rules of Receiver ........................... 9 
      6.3. Processing Rules of Relay Agent ....................... 10 
      6.4. Timestamp Check ....................................... 11 
   7. Security Considerations .................................... 12 
   8. IANA Considerations ........................................ 13 
   9. Acknowledgments ............................................ 14 
   10. References ................................................ 14 
      10.1. Normative References ................................. 14 
      10.2. Informative References ............................... 14 
    

 
 
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1. Introduction 

   The Dynamic Host Configuration Protocol for IPv6 (DHCPv6 [RFC3315]) 
   enables DHCPv6 servers to pass configuration parameters. It offers 
   configuration flexibility. If not secured, DHCPv6 is vulnerable to 
   various attacks, particularly spoofing attacks. 

   This document analyzes the security issues of DHCPv6 in details. This 
   document provides mechanisms for improving the security of DHCPv6: 

      - the identity of a DHCPv6 message sender, which can be a DHCPv6 
        server, a relay agent or a client, can be verified by a 
        receiver. 

      - The integrity of DHCPv6 messages can be checked by the receiver 
        of the message. 

   The security mechanisms specified in this document is based on self-
   generated public/private key pairs. It also integrates timestamps for 
   anti-replay. The authentication procedure defined in this document 
   may depend on either deployed Public Key Infrastructure (PKI, 
   [RFC5280]) or pre-configured sender's public key. However, the 
   deployment of PKI or pre-configuration is out of the scope. 

   Secure DHCPv6 is applicable in environments where physical security 
   on the link is not assured (such as over wireless) and attacks on 
   DHCPv6 are a concern. 

2. Terminology 

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 
   document are to be interpreted as described in [RFC2119]. 

3. Security Overview of DHCPv6 

   DHCPv6 is a client/server protocol that provides managed 
   configuration of devices. It enables DHCPv6 server to automatically 
   configure relevant network parameters on clients. In the basic DHCPv6 
   specification [RFC3315], security of DHCPv6 message can be improved 
   in a few aspects. 

   a)   The basic DHCPv6 specifications can optionally authenticate the 
      origin of messages and validate the integrity of messages using an 
      authentication option with a symmetric key pair. [RFC3315] relies 
      on pre-established secret keys. For any kind of meaningful 
      security, each DHCPv6 client would need to be configured with its 
      own secret key; [RFC3315] provides no mechanism for doing this. 
 
 
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      For the key of the hash function, there are two key management 
      mechanisms. Firstly, the key management is out of band, usually 
      manual, i.e., operators set up key database for both server and 
      client before running DHCPv6. Usually multiple keys are deployed 
      one a time and key id is used to specify which key is used. 

      Manual key distribution runs counter to the goal of minimizing the 
      configuration data needed at each host. [RFC3315] provides an 
      additional mechanism for preventing off-network timing attacks 
      using the Reconfigure message: the Reconfigure Key authentication 
      method. However, this method provides no message integrity or 
      source integrity check. This key is transmitted in plaintext. 

      Comparing to this, the public/private key pair security mechanism 
      only require a key pair on the sender. The key management 
      mechanism is very simple. 

   b)   Communication between a server and a relay agent, and 
      communication between relay agents, can be secured through the use 
      of IPsec, as described in section 21.1 in [RFC3315]. However, 
      IPsec is quite complicated. A simpler security mechanism, which 
      can be easier to deploy, is desirable. 

4. Secure DHCPv6 Overview 

   To solve the above mentioned security issues, we introduce the use of 
   public/private key pair mechanism into DHCPv6, also with timestamp. 
   The authority of the sender may depend on either pre-configuration 
   mechanism or PKI. By combining with the signatures, sender identity 
   can be verified and messages protected. 

   This document introduces a Secure DHCPv6 mechanism that uses the 
   public/private key pair to secure the DHCPv6 protocol. It assumes:  
   a) the secured DHCPv6 message sender already has a public/private key 
   pair; b) the receiver has already been have the public key of the 
   sender, which may be pre-configured or recorded from previous 
   communications, or the public key of CA (Certificate Authority), 
   which issues the sender's certificate and is trusted by the receiver. 

   In this document, we introduce a key/certificate option and two 
   signature options with a corresponding verification mechanism. 
   Timestamp is integrated into signature options. A DHCPv6 message 
   (from a server, a relay agent or a client), with a key/certificate 
   option and carry a digital signature, can be verified by the receiver 
   for both the timestamp and authentication, then process the payload 
   of the DHCPv6 message only if the validation is successful. 

   This improves communication security of DHCPv6 messages. The 
   authentication options [RFC3315] may also be used for replay 
   protection. 
 
 
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   Because the sender can be a DHCPv6 server, a relay agent or a client, 
   the end-to-end security protection can be from DHCPv6 servers to 
   relay agents or clients, or from clients to DHCPv6 servers. Relay 
   agents MAY add its own Secure DHCPv6 options in Relay-Forward 
   messages when transmitting client messages to the server. 

4.1. New Components 

   The components of the solution specified in this document are as 
   follows: 

      - A public/private key pair has been generated by a node itself. 
        The node may request a CA to sign its public key to get a 
        trustable certificate, which contains the original public key. 
        Two new DHCPv6 option are defined to carry the public key or 
        the certificate of the sender. 

      - Signatures signed by private key protect the integrity of the 
        DHCPv6 messages and authenticate the identity of the sender. 

      - Timestamp, a value that indicates the relative time in second. 

4.2. Support for algorithm agility 

   Hash functions are the fundamental security mechanism. "...they have 
   two security properties: to be one way and collision free." "The 
   recent attacks have demonstrated that one of those security 
   properties is not true." [RFC4270] It is theoretically possible to 
   perform collision attacks against the "collision-free" property. 

   Following the approach recommended by [RFC4270] and [NewHash], recent 
   analysis shows none of these attacks are currently possible, 
   according to [RFC6273]. "The broken security property will not affect 
   the overall security of many specific Internet protocols, the 
   conservative security approach is to change hash algorithms." 
   [RFC4270] 

   However, these attacks indicate the possibility of future real-world 
   attacks. Therefore, we have to take into account that attacks will 
   improved in the future, and provide a support for multiple hash 
   algorithms. Our mechanism, in this document, supports not only hash 
   algorithm agility but also signature algorithm agility. 

   The support for algorithm agility in this document is mainly a 
   unilateral notification model from a sender to a receiver. If the 
   receiver cannot support the algorithm provided by the sender, it 
   takes the risk itself. Senders in a same network do not have to 
   upgrade to a new algorithm simultaneously. 

 
 
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5. Extensions for Secure DHCPv6 

   This section extends DHCPv6. Three new options have been defined. The 
   new options MUST be supported in the Secure DHCPv6 message exchange. 

5.1. Key/Certificate Option 

   The Key/Certificate option carries the public key or certificate of 
   the sender. The format of the Public Key option is described 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 
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
       |     OPTION Key/Certificate    |         option-len            | 
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
       |    K/C Flag   |                                               | 
       +-+-+-+-+-+-+-+-+                                               . 
       .        Public Key or Certificate (variable length)            . 
       .                                                               . 
       |                                                               | 
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

       option-code     OPTION_KC_PARAMETER (TBA1). 

       option-len      1+ length of public key/certificate in octets. 

       K/C Flag        Flag to indicate whether the value is a public 
                       key or certificate. 00x for public key; FFx for 
                       certificate. Other values may be extended in the 
                       future. 

       Public key      A variable-length field containing public key or 
                       certificate. 

5.2. Signature Option 

   The Signature option allows public key-based signatures to be 
   attached to a DHCPv6 message. The Signature option could be any place 
   within the DHCPv6 message. It protects the entire DHCPv6 header and 
   options, except for the Signature option itself and the 
   Authentication Option. The format of the Signature option is 
   described 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 
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
       |     OPTION_SIGNATURE          |        option-len             | 
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
       |           HA-id               |            SA-id              | 
 
 
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       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
       |                     Timestamp (64-bit)                        | 
       |                                                               | 
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
       |                                                               | 
       .                    Signature (variable length)                . 
       .                                                               . 
       .                                                     +-+-+-+-+-+ 
       |                                                     | Padding | 
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

       option-code     OPTION_SIGNATURE (TBA2). 

       option-len      12 + Length of Signature field and Padding field 
                       in octets. 

       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 initial 
                       values are assigned for SHA-1 is 0x0001. 

       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 initial values are assigned for 
                       RSASSA-PKCS1-v1_5 is 0x0001. 

       Reserved        A 16-bit field reserved for future use. The 
                       value MUST be initialized to zero by the sender, 
                       and MUST be ignored by the receiver. 

       Timestamp       The current time of day (NTP-format timestamp 
                       [RFC5905], a 64-bit unsigned fixed-point number, 
                       in seconds relative to 0h on 1 January 1900.). 
                       It can reduce the danger of replay attacks. 

       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 128-bit Source IPv6 Address. 
                        
                       2. The 128-bit Destination IPv6 Address. 
 
 
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                       3. The DHCPv6 message header. 
                        
                       4. All DHCPv6 options except for the Signature 
                       option and the Authentication Option. 
                        
                       5. The content between the option-len field and 
                       the signature field in this Signature option, in 
                       the format described above. 

       Padding        This variable-length field contains padding, as 
                       many bits long as remain after the end of the 
                       signature. This padding is only needed if the 
                       length of signature is not a multiple of 8  
                       bits. 

   Note: a Relay-Reply message is constructed by a DHCPv6 server in 
   segments. The server first constructs the server message for client, 
   which includes a Signature Option that covers the server message. In 
   the signed data, the destination address is the address of the  
   client. It then constructs the Relay-Reply message by encapsulating 
   the server message into a Relay Message Option. If there is 
   additional option for relay, the server MUST include another 
   Signature Option, which covers the entire Relay-Reply message. In the 
   signed data, the destination address is the address of the target 
   relay agent. 

6. Processing Rules and Behaviors 

6.1. Processing Rules of Sender 

   The sender of a Secure DHCPv6 message could be a DHCPv6 server, a 
   DHCPv6 relay agent or a DHCPv6 client.  

   The node MUST have a public/private key pair in order to create 
   Secure DHCPv6 messages. The node may have a certificate which is 
   signed by a CA trusted by both sender and receiver. 

   To support Secure DHCPv6, the Secure DHCPv6 enabled sender MUST 
   construct the DHCPv6 message following the rules defined  
   in [RFC3315]. 

   A Secure DHCPv6 message MUST contain both the Key/Certificate option 
   and the Signature option, except for Relay-forward and Relay-reply 
   Messages. 

   Senders SHOULD set the Timestamp field to the current time, according 
   to their real time clocks. 

 
 
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   If a relay agent adds its own options in a Relay-forward message, it 
   MUST contain the Key/Certificate option and the Signature option. If 
   it does not any add new options it MUST NOT add either the 
   Key/Certificate option or the Signature option into Relay-forward 
   message. If there are more than a number of Relay agents (the number 
   depends on the lengths of public key and signature, typical number is 
   four) in the way and each of them adds their own options, it may 
   exceed the IPv6 MTU. However, this can be considered as a rare 
   deployment scenario. 

   Relay-reply Messages MUST NOT contain the Key/Certificate option 
   since it appears in the Relay Message Option. If a server adds 
   addition options for relay agents in Relay-reply message, it MUST 
   contain a Signature Option. If it does not add any addition options, 
   it MUST NOT add the Signature Option into the Relay-reply message. 

   The Signature option MUST be constructed as explained in Section 5.2. 
   It protects the message header and the message payload and all DHCPv6 
   options except for the Signature option itself and the Authentication 
   Option. 

6.2. Processing Rules of Receiver 

   When receiving a DHCPv6 message (except for Relay-Forward and  
   Relay-Reply messages), a Secure DHCPv6 enabled receiver SHOULD 
   discard the DHCPv6 message if either the Key/Certificate option or 
   the Signature option is absent. If both options are absent, the 
   receiver MAY fall back the unsecure DHCPv6 model. 

   The receiver SHOULD first check the authority of this sender. If the 
   sender uses public key in the Key/Certificate option, the receiver 
   SHOULD trust it by finding a match public key from the local trust 
   public key list, which is pre-configured or recorded from previous 
   communications. If the sender uses certificate in the Key/Certificate 
   option, the receiver SHOULD validation the sender's certificate 
   following the rules defined in [RFC5280]. An implementation may then 
   create a local trust certificate record, too. The receiver may choose 
   to further process the message from an unauthorized sender so that a 
   leap of faith may be built up. 

   Then, the receiver MUST verify the Signature and check timestamp. The 
   order of two procedures is left as an implementation decision. It is 
   RECOMMENDED to check timestamp first, because signature verification 
   is much more computational expensive. 

   The signature field verification MUST show that the signature has 
   been calculated as specified in Section 5.2. 

   Only the messages that get through both the signature verifications 
   and timestamp check are accepted as secured DHCPv6 messages and 
 
 
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   continue to be handled for their contained DHCPv6 options as defined 
   in [RFC3315]. Messages that do not pass the above tests MUST be 
   discarded or treated as unsecure messages. 

   The receiver MAY record the verified public key or certificate for 
   future authentications. 

   Furthermore, the node that supports the verification of the Secure 
   DHCPv6 messages MAY record the following information: 

       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 [RSA]. 

   A Relay-forward message without any addition option to Relay Message 
   option or a Relay-forward message with both addition options and the 
   Signature option is accepted for a Secure DHCPv6 enabled server. 
   Otherwise, the message SHOULD be discarded or treated as unsecure 
   message. If Signature option is presented in the Relay-forward 
   message, the signature verification and timestamp check are needed. 
   The server MUST also verify signature for the encapsulated client 
   DHCPv6 message in the Relay Message Option. 

   A Relay-reply message without any addition option to Relay Message 
   option or a Relay-reply message with both addition options and the 
   Signature Option is accepted for a Secure DHCPv6 enabled server. 
   Otherwise, the message SHOULD be discarded or treated as unsecure 
   message. If the Signature Option is presented in the Relay-reply 
   message, the signature verification and timestamp check are needed. 
   The relay agents obtain the public key or certificate of the server 
   from the Key/Certificate option encapsulated in the Relay Message 
   option. 

6.3. Processing Rules of Relay Agent 

   To support Secure DHCPv6, relay agents MUST follow the same 
   processing rules defined in [RFC3315]. 

   In the client-relay-server scenario, the relay agent MAY verify the 
   signature as a receiver before relaying the client message further, 
   following verification procedure define in Section 6.2. In the case 
   of failure, it MUST discard the DHCPv6 message. However, the 
   verification procedure on relay agents does not save the load of the 

 
 
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   DHCPv6 server. The server still MUST verify the signature by itself 
   in order to prevent the attack between the relay agent and server. 

   In the server-relay-client scenario, if the Signature Option and 
   addition options are presented, the relay agent MUST verify the 
   signature before relaying the server message further, following 
   verification procedure define in Section 6.2. In the case of failure, 
   it MUST discard the DHCPv6 message. 

   The relay agent MAY also verify the signature for the encapsulated 
   DHCPv6 message in the Relay Message Option. This can be helpful if 
   the DHCPv6 response traverses a separate administrative domain, or if 
   the relay agent is in a separate administrative domain. However, this 
   is not necessary because the DHCPv6 client validation will catch any 
   modification to the response. 

6.4. Timestamp Check 

   Receivers 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. 

   To facilitate timestamp checking, each receiver SHOULD store the 
   following information for each sender: 

    o  The receive time of the last received and accepted DHCPv6  
       message. This is called RDlast. 

    o  The time stamp in the last received and accepted DHCPv6 message. 
       This is called TSlast. 

   An accepted DHCPv6 message is any successfully verified (for both 
   timestamp check and signature verification) DHCPv6 message from the 
   given peer. It initiates the update of the above variables. 

   Receivers SHOULD then check the Timestamp field as follows: 

    o  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: 

          -Delta < (RDnew - TSnew) < +Delta 

       The RDnew and TSnew values SHOULD be stored in the cache as  
       RDlast and TSlast. 

 
 
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    o  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 SEND message: 

          TSnew + fuzz > TSlast + (RDnew - RDlast) x (1 - drift) - fuzz 

       If this inequality does not hold, the receiver SHOULD silently 
       discard the message. If, on the other hand, the inequality holds, 
       the receiver SHOULD process the message. 

       Moreover, if the above inequality holds and TSnew > TSlast, the 
       receiver SHOULD update RDlast and TSlast. Otherwise, the receiver 
       MUST NOT update RDlast or TSlast. 

   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. 

7. Security Considerations 

   This document provides new security features to the DHCPv6 protocol. 

   Using public key based security mechanism and its verification 
   mechanism in DHCPv6 message exchanging provides the authentication 
   and data integrity protection. Timestamp mechanism provides anti-
   replay function. 

   The Secure DHCPv6 mechanism is based on the pre-condition that the 
   receiver knows the public key of senders or the sender's certificate 
   can be verified through a trust CA. It prevents DHCPv6 server 
   spoofing. The clients may decline the DHCPv6 messages from 
   unknown/unverified servers, which may be fake servers; or may prefer 
   DHCPv6 messages from known/verified servers over unsigned messages or 
   messages from unknown/unverified servers. The pre-configuration 
   operation also needs to be protected, which is out of scope. The 
   deployment of PKI is also out of scope. 

   However, when a DHCPv6 client first encounters a new public key or 
   new unverified certificate, it can make a leap of faith. If the 
   DHCPv6 server that used that public key/certificate is in fact 
   legitimate, then all future communication with that DHCPv6 server can 
   be protected by caching the public key. This does not provide 
   complete security, but it limits the opportunity to mount an attack 
   on a specific DHCPv6 client to the first time it communicates with a 
   new DHCPv6 server. 
 
 
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   Downgrade attacks cannot be avoided if nodes are configured to accept 
   both secured and unsecured messages. A future specification may 
   provide a mechanism on how to treat unsecured DHCPv6 messages. 

   [RFC6273] has analyzed possible threats to the hash algorithms used 
   in SEND. Since the 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 the Secure DHCPv6. 

   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. 

   Attacks against time synchronization protocols such as NTP [RFC5905] 
   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 SEND nodes keep independently maintained clocks or 
   apply suitable security measures for the time synchronization 
   protocols. 

8. IANA Considerations 

   This document defines two new DHCPv6 [RFC3315] options, which MUST be 
   assigned Option Type values within the option numbering space for 
   DHCPv6 messages: 

       The Key/Certificate Parameter Option (TBA1), described in Section 
       5.1. 

       The Signature Option (TBA2), described in Section 5.2. 

   This document defines two new registries that have been created and 
   are maintained by IANA. Initial values for these registries are given 
   below. Future assignments are to be made through Standards Action 
   [RFC5226]. Assignments for each registry consist of a name, a value 
   and a RFC number where the registry is defined. 

   Hash Algorithm for Secure DHCPv6. The values in this name space are 
   16-bit unsigned integers. The following initial values are assigned 
   for Hash Algorithm for Secure DHCPv6 in this document: 

             Name        |  Value  |  RFCs 
      -------------------+---------+------------ 
 
 
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            Reserved     |  0x0000 | this document 
            SHA-1        |  0x0001 | this document 
            SHA-256      |  0x0002 | this document 

   Signature Algorithm for Secure DHCPv6. The values in this name space 
   are 16-bit unsigned integers. The following initial values are 
   assigned for Signature Algorithm for Secure DHCPv6 in this document: 

             Name        |  Value  |  RFCs 
      -------------------+---------+------------ 
            Reserved     |  0x0000 | this document 
       RSASSA-PKCS1-v1_5 |  0x0001 | this document 

9. Acknowledgments 

   The authors would like to thank Bernie Volz, Ted Lemon, Ralph Droms, 
   Jari Arkko, Sean Turner, Stephen Kent, Thomas Huth, David Schumacher, 
   Dacheng Zhang, Francis Dupont and other members of the IETF DHC 
   working groups for their valuable comments. 

10. References 

10.1. Normative References 

   [RFC3315] R. Droms, et al., "Dynamic Host Configure Protocol for 
             IPv6", RFC 3315, July 2003. 

   [RFC5280] D. Cooper, S. Santesson, S. Farrell, S. Boeyen, R. Housley, 
             and W. Polk, "Internet X.509 Public Key Infrastructure 
             Certificate and Certificate Revocation List (CRL) Profile", 
             RFC 5280, May 2008. 

   [RFC5905] D. Mills, J. Martin, Ed., J. Burbank and W. Kasch, "Network 
             Time Protocol Version 4: Protocol and Algorithms 
             Specification", RFC 5905, June 2010. 

10.2. Informative References 

   [RFC2119] S. Bradner, "Key words for use in RFCs to Indicate 
             Requirement Levels", c, March 1997. 

   [RFC4270] Hoffman, P. and B. Schneier, "Attacks on Cryptographic 
             Hashes in Internet Protocols", RFC 4270, November 2005. 

   [RFC5226] T. Narten and H. Alvestrand, "Guidelines for Writing an 
             IANA Considerations Section in RFCs", RFC 5226, May 2008. 

   [RFC6273] A. Kukec, S. Krishnan and S. Jiang "The Secure Neighbor 
             Discovery (SEND) Hash Threat Analysis", RFC 6274, June  
             2011. 
 
 
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   [NewHash] S.Bellovin and E. Rescorla, "Deploying a New Hash 
             Algorithm", November 2005. 

   [RSA]    RSA Laboratories, "RSA Encryption Standard, Version 2.1", 
             PKCS 1, November 2002. 

   [sha-1]  National Institute of Standards and Technology, "Secure 
             Hash Standard", FIBS PUB 180-1, April 1995, 
             http://www.itl.nist.gov/fipspubs/fip180-1.htm. 

    

   Author's Addresses 

   Sheng Jiang 
   Huawei Technologies Co., Ltd 
   Q14, Huawei Campus 
   No.156 Beiqing Road 
   Hai-Dian District, Beijing  100095 
   P.R. China 
   EMail: jiangsheng@huawei.com 
    
   Sean Shen 
   CNNIC 
   4, South 4th Street, Zhongguancun 
   Beijing 100190 
   P.R. China 
   EMail: shenshuo@cnnic.cn 

 
 
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