draft-ietf-6lo-ap-nd-04.txt   draft-ietf-6lo-ap-nd-05.txt 
6lo B. Sarikaya 6lo P. Thubert, Ed.
Internet-Draft Internet-Draft Cisco
Updates: 6775 (if approved) P. Thubert Updates: 6775 (if approved) B. Sarikaya
Intended status: Standards Track Cisco Intended status: Standards Track
Expires: May 18, 2018 M. Sethi Expires: August 3, 2018 M. Sethi
Ericsson Ericsson
November 14, 2017 January 30, 2018
Address Protected Neighbor Discovery for Low-power and Lossy Networks Address Protected Neighbor Discovery for Low-power and Lossy Networks
draft-ietf-6lo-ap-nd-04 draft-ietf-6lo-ap-nd-05
Abstract Abstract
This document defines an extension to 6LoWPAN Neighbor Discovery RFC This document defines an extension to 6LoWPAN Neighbor Discovery (ND)
6775. Nodes supporting this extension compute a cryptographic Owner [RFC6775][I-D.ietf-6lo-rfc6775-update] called Address Protected ND
Unique Interface ID and associate it with one or more of their (AP-ND); AP-ND protects the owner of an address against address theft
Registered Addresses. Once an address is registered with a and impersonation inside a low-power and lossy network (LLN). Nodes
Cryptographic ID, only the owner of that ID can modify the anchor supporting this extension compute a cryptographic Owner Unique
Interface ID and associate it with one or more of their Registered
Addresses. The Cryptographic ID uniquely identifies the owner of the
Registered Address and can be used for proof-of-ownership. It is
used in 6LoWPAN ND in place of the EUI-64-based unique ID that is
associated with the registration. Once an address is registered with
a Cryptographic ID, only the owner of that ID can modify the anchor
state information of the Registered Address, and Source Address state information of the Registered Address, and Source Address
Validation can be enforced. Validation can be enforced.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 18, 2018. This Internet-Draft will expire on August 3, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Updating RFC 6775 . . . . . . . . . . . . . . . . . . . . . . 4 3. Updating RFC 6775 . . . . . . . . . . . . . . . . . . . . . . 5
4. New Fields and Options . . . . . . . . . . . . . . . . . . . 5 4. New Fields and Options . . . . . . . . . . . . . . . . . . . 5
4.1. New Crypto-ID . . . . . . . . . . . . . . . . . . . . . . 5 4.1. Encoding the Public Key . . . . . . . . . . . . . . . . . 5
4.2. Updated EARO . . . . . . . . . . . . . . . . . . . . . . 6 4.2. New Crypto-ID . . . . . . . . . . . . . . . . . . . . . . 6
4.3. New Crypto-ID Parameters Option . . . . . . . . . . . . . 7 4.3. Updated EARO . . . . . . . . . . . . . . . . . . . . . . 6
5. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 9 4.4. Crypto-ID Parameters Option . . . . . . . . . . . . . . . 7
5.1. Protocol Scope . . . . . . . . . . . . . . . . . . . . . 9 4.5. Nonce Option . . . . . . . . . . . . . . . . . . . . . . 9
5.2. Protocol Flows . . . . . . . . . . . . . . . . . . . . . 10 4.6. NDP Signature Option . . . . . . . . . . . . . . . . . . 9
5.3. Multihop Operation . . . . . . . . . . . . . . . . . . . 12 5. Protocol Scope . . . . . . . . . . . . . . . . . . . . . . . 9
6. Security Considerations . . . . . . . . . . . . . . . . . . . 12 6. Protocol Flows . . . . . . . . . . . . . . . . . . . . . . . 10
7. IANA considerations . . . . . . . . . . . . . . . . . . . . . 13 6.1. First Exchange with a 6LR . . . . . . . . . . . . . . . . 11
7.1. Crypto Type Registry . . . . . . . . . . . . . . . . . . 13 6.2. Multihop Operation . . . . . . . . . . . . . . . . . . . 12
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14 7. Security Considerations . . . . . . . . . . . . . . . . . . . 14
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 7.1. Inheriting from RTC 3971 . . . . . . . . . . . . . . . . 14
9.1. Normative References . . . . . . . . . . . . . . . . . . 14 7.2. Related to 6LoWPAN ND . . . . . . . . . . . . . . . . . . 15
9.2. Informative references . . . . . . . . . . . . . . . . . 14 7.3. OUID Collisions . . . . . . . . . . . . . . . . . . . . . 16
Appendix A. Requirements Addressed in this Document . . . . . . 16 8. IANA considerations . . . . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17 8.1. CGA Message Type . . . . . . . . . . . . . . . . . . . . 16
8.2. Crypto-Type Subregistry . . . . . . . . . . . . . . . . . 16
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 17
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 17
10.1. Normative References . . . . . . . . . . . . . . . . . . 17
10.2. Informative references . . . . . . . . . . . . . . . . . 18
Appendix A. Requirements Addressed in this Document . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21
1. Introduction 1. Introduction
"Neighbor Discovery Optimizations for 6LoWPAN networks" [RFC6775] "Neighbor Discovery Optimizations for 6LoWPAN networks" [RFC6775]
(6LoWPAN ND) adapts the classical IPv6 ND protocol [RFC4861][RFC4862] (6LoWPAN ND) adapts the classical IPv6 ND protocol [RFC4861][RFC4862]
(IPv6 ND) for operations over a constrained low-power and lossy (IPv6 ND) for operations over a constrained low-power and lossy
network (LLN). In particular, 6LoWPAN ND introduces a unicast host network (LLN). In particular, 6LoWPAN ND introduces a unicast host
address registration mechanism that contributes to reduce the use of address registration mechanism that contributes to reduce the use of
multicast messages that are present in the classical IPv6 ND multicast messages that are present in the classical IPv6 ND
protocol. 6LoWPAN ND defines a new Address Registration Option (ARO) protocol. 6LoWPAN ND defines a new Address Registration Option (ARO)
skipping to change at page 3, line 8 skipping to change at page 3, line 28
(DAC) messages between the 6LR and the 6LoWPAN Border Router (6LBR). (DAC) messages between the 6LR and the 6LoWPAN Border Router (6LBR).
In LLN networks, the 6LBR is the central repository of all the In LLN networks, the 6LBR is the central repository of all the
registered addresses in its domain. registered addresses in its domain.
The registration mechanism in 6LoWPAN ND [RFC6775] prevents the use The registration mechanism in 6LoWPAN ND [RFC6775] prevents the use
of an address if that address is already present in the subnet (first of an address if that address is already present in the subnet (first
come first serve). In order to validate address ownership, the come first serve). In order to validate address ownership, the
registration mechanism enables the 6LR and 6LBR to validate claims registration mechanism enables the 6LR and 6LBR to validate claims
for a registered address with an associated Owner Unique Interface for a registered address with an associated Owner Unique Interface
IDentifier (OUID). 6LoWPAN ND specifies that the OUID is derived from IDentifier (OUID). 6LoWPAN ND specifies that the OUID is derived from
the MAC address of the device (EUI-64), which can be spoofed. the MAC address of the device (using the 64-bit Extended Unique
Therefore, any node connected to the subnet and aware of a Identifier EUI-64 address format specified by IEEE), which can be
spoofed. Therefore, any node connected to the subnet and aware of a
registered-address-to-OUID mapping could effectively fake the OUID, registered-address-to-OUID mapping could effectively fake the OUID,
steal the address and redirect traffic for that address towards a steal the address and redirect traffic for that address towards a
different 6LN. The "Update to 6LoWPAN ND" different 6LN. The "Update to 6LoWPAN ND"
[I-D.ietf-6lo-rfc6775-update] defines an Extended ARO (EARO) option [I-D.ietf-6lo-rfc6775-update] defines an Extended ARO (EARO) option
that allows to transport alternate forms of OUIDs, and is a that allows to transport alternate forms of OUIDs, and is a
prerequisite for this specification. prerequisite for this specification.
According to this specification, a 6LN generates a cryptographic ID According to this specification, a 6LN generates a cryptographic ID
(Crypto-ID) and places it in the OUID field in the registration of (Crypto-ID) and places it in the OUID field in the registration of
one (or more) of its addresses with the 6LR(s) that the 6LN uses as one (or more) of its addresses with the 6LR(s) that the 6LN uses as
default router(s). Proof of ownership of the cryptographic ID default router(s). Proof of ownership of the cryptographic ID
(Crypto-ID) is passed with the first registration to a given 6LR, and (Crypto-ID) is passed with the first registration exchange to a new
enforced at the 6LR, in a new Crypto-ID Parameters Option (CIPO). 6LR, and enforced at the 6LR. The 6LR validates ownership of the
The 6LR validates ownership of the cryptographic ID upon the creation cryptographic ID before it can create a registration state, or a
of a registration state, or a change in the anchor information, such change the anchor information, that is the Link-Layer Address and
as Link-Layer Address and associated Layer-2 cryptographic material. associated parameters, in an existing registration state.
The protected address registration protocol proposed in this document The protected address registration protocol proposed in this document
enables the enforcement of Source Address Validation (SAVI) enables the enforcement of Source Address Validation (SAVI)
[RFC7039], which ensures that only the correct owner uses a [RFC7039], which ensures that only the correct owner uses a
registered address in the source address field in IPv6 packets. registered address in the source address field in IPv6 packets.
Consequently, a 6LN that sources a packet has to use a 6LR to which Consequently, a 6LN that sources a packet has to use a 6LR to which
the source address of the packet is registered to forward the packet. the source address of the packet is registered to forward the packet.
The 6LR maintains state information for the registered addressed, The 6LR maintains state information for the registered addressed,
including the MAC address, and a link-layer cryptographic key including the MAC address, and a link-layer cryptographic key
associated with the 6LN. In SAVI-enforcement mode, the 6LR allows associated with the 6LN. In SAVI-enforcement mode, the 6LR allows
only packets from a connected Host if the connected Host owns the only packets from a connected Host if the connected Host owns the
registration of the source address of the packet. registration of the source address of the packet.
The 6lo adaptation layer framework ([RFC4944], [RFC6282]) expects The 6lo adaptation layer framework ([RFC4944], [RFC6282]) expects
that a device forms its IPv6 addresses based on Layer-2 address, so that a device forms its IPv6 addresses based on Layer-2 address, so
as to enable a better compression. This is incompatible with "Secure as to enable a better compression. This is incompatible with "Secure
Neighbor Discovery (SEND)" [RFC3971] and "Cryptographically Generated Neighbor Discovery (SeND)" [RFC3971] and "Cryptographically Generated
Addresses (CGAs)" [RFC3972], which derive the Interface ID (IID) in Addresses (CGAs)" [RFC3972], which derive the Interface ID (IID) in
the IPv6 addresses from cryptographic material. "Privacy the IPv6 addresses from cryptographic material. "Privacy
Considerations for IPv6 Address Generation Mechanisms" [RFC7721] Considerations for IPv6 Address Generation Mechanisms" [RFC7721]
places additional recommendations on the way addresses should be places additional recommendations on the way addresses should be
formed and renewed. formed and renewed.
This document specifies that a device may form and register addresses This document specifies that a device may form and register addresses
at will, without a constraint on the way the address is formed or the at will, without a constraint on the way the address is formed or the
number of addresses that are registered in parallel. It enables to number of addresses that are registered in parallel. It enables to
protect multiple addresses with a single cryptographic material and protect multiple addresses with a single cryptographic material and
skipping to change at page 4, line 21 skipping to change at page 4, line 41
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
Readers are expected to be familiar with all the terms and concepts Readers are expected to be familiar with all the terms and concepts
that are discussed in [RFC3971], [RFC3972], [RFC4861], [RFC4919], that are discussed in [RFC3971], [RFC3972], [RFC4861], [RFC4919],
[RFC6775], and [I-D.ietf-6lo-backbone-router] which proposes an [RFC6775], and [I-D.ietf-6lo-backbone-router] which proposes an
evolution of [RFC6775] for wider applicability. evolution of [RFC6775] for wider applicability.
This document defines Crypto-ID as an identifier of variable size This document defines Crypto-ID as an identifier of variable size
which in most cases is 64 bits long. It is generated using which in most cases is 64 bits long. It is generated using
cryptographic means explained later in this document Section 4.1. cryptographic means explained later in this document Section 4.2.
"Elliptic Curves for Security" [RFC7748] and "Edwards-Curve Digital "Elliptic Curves for Security" [RFC7748] and "Edwards-Curve Digital
Signature Algorithm (EdDSA)" [RFC8032] provides information on Signature Algorithm (EdDSA)" [RFC8032] provides information on
Elliptic Curve Cryptography (ECC) and a (twisted) Edwards curve, Elliptic Curve Cryptography (ECC) and a (twisted) Edwards curve,
Ed25519, which can be used with this specification. "Alternative Ed25519, which can be used with this specification. "Alternative
Elliptic Curve Representations" Elliptic Curve Representations"
[I-D.struik-lwip-curve-representations] provides additional [I-D.struik-lwig-curve-representations] provides additional
information on how to represent Montgomery curves and (twisted) information on how to represent Montgomery curves and (twisted)
Edwards curves as curves in short-Weierstrass form and illustrates Edwards curves as curves in short-Weierstrass form and illustrates
how this can be used to implement elliptic curve computations using how this can be used to implement elliptic curve computations using
existing implementations that already implement, e.g., ECDSA and ECDH existing implementations that already implement, e.g., ECDSA and ECDH
using NIST [FIPS186-4] prime curves. using NIST [FIPS-186-4] prime curves.
The document also conforms to the terms and models described in The document also conforms to the terms and models described in
[RFC5889] and uses the vocabulary and the concepts defined in [RFC5889] and uses the vocabulary and the concepts defined in
[RFC4291] for the IPv6 Architecture. Finally, common terminology [RFC4291] for the IPv6 Architecture. Finally, common terminology
related to Low power And Lossy Networks (LLN) defined in [RFC7102] is related to Low power And Lossy Networks (LLN) defined in [RFC7102] is
also used. also used.
3. Updating RFC 6775 3. Updating RFC 6775
This specification defines a cryptographic identifier (Crypto-ID) This specification defines a cryptographic identifier (Crypto-ID)
that can be used as a replacement to the MAC address in the OUID that can be used as a replacement to the MAC address in the OUID
field of the EARO option; the computation of the Crypto-ID is field of the EARO option; the computation of the Crypto-ID is
detailed in Section 4.1. A node in possession of the necessary detailed in Section 4.2. A node in possession of the necessary
cryptographic material SHOULD use Crypto-ID by default as OUID in its cryptographic material SHOULD use Crypto-ID by default as OUID in its
registration. Whether a OUID is a Crypto-ID is indicated by a new registration. Whether a OUID is a Crypto-ID is indicated by a new
"C" flag in the NS(EARO) message. "C" flag in the NS(EARO) message.
This specification introduces a new option, the CIPO, that is used to In order to prove its ownership of a Crypto-ID, the registering node
prove ownership of the Crypto-ID. A node that registers for the needs to produce the parameters that where used to build it, as well
first time to a 6LR SHOULD place a CIPO option in its registration. as a nonce and a signature that will prove that it has the private
However, it is not expected to place the option in the periodic key that corresponds to the public key that was used to build the
refresher registrations for that address, or to register other Crypto-ID. This specification adds the capability to carry new
addresses with the same OUID. When a 6LR receives a NS(EARO) options in the NS(EARO) and the NBA(EARO). These options are a
registration with a new Crypto-ID as a OUID, it SHOULD challenge by variation of the CGA Option Section 4.4, a Nonce option and a
responding with a NA(EARO) with a status of "Validation Requested". variation of the RSA Signature option Section 4.6 in the NS(EARO) and
This process of validation MAY be skipped in networks where there is a Nonce option in the NA(EARO).
no mobility.
The challenge MUST also be triggered in the case of a registration 4. New Fields and Options
for which the Source Link-Layer Address is not consistent with a
state that already exists either at the 6LR or the 6LBR. In the
latter case, the 6LBR returns a status of "Validation Requested" in
the DAR/DAC exchange, which is echoed by the 6LR in the NA (EARO)
back to the registering node. This flow should not alter a
preexisting state in the 6LR or the 6LBR.
Upon receiving a NA(EARO) with a status of "Validation Requested", In order to avoid an inflation of ND option types, this specification
the registering node SHOULD retry its registration with a CIPO option reuses / extends options defined in SEND [RFC3971] and 6LoWPAN ND
that proves its ownership of the Crypto-ID. [RFC6775][I-D.ietf-6lo-rfc6775-update]. This applies in particular
to the CGA option and the RSA Signature Option. This specification
provides aliases for the specific variations of those options as used
in AP-ND. The presence of the EARO option in the NS/NA messages
indicates that the options are to be understood as specified in this
document. A router that would receive a NS(EARO) and try to process
it as a SEND message will find that the signature does not match and
drop the packet.
If the 6LR cannot validate the CIPO, it responds with a status of 4.1. Encoding the Public Key
"Validation Failed". After receiving a NA(EARO) with a status of
"Validation Failed", the registering node MUST NOT use this Crypto-ID
for registering with that 6LR.
4. New Fields and Options Public Key is the most important parameter in CGA Parameters (sent by
6LN in an NS message). ECC Public Key could be in uncompressed form
or in compressed form where the first octet of the OCTET STRING is
0x04 and 0x02 or 0x03, respectively. Point compression can further
reduce the key size by about 32 octets.
4.1. New Crypto-ID 4.2. New Crypto-ID
Elliptic Curve Cryptography (ECC) is used to calculate the Crypto-ID. Elliptic Curve Cryptography (ECC) is used to calculate the Crypto-ID.
Each 6LN using a Crypto-ID for registration MUST have a public/ Each 6LN using a Crypto-ID for registration MUST have a public/
private key pair. The digital signature is constructed by using the private key pair. The digital signature is constructed by using the
6LN's private key over its EUI-64 (MAC) address. The signature value 6LN's private key over its EUI-64 (MAC) address. The signature value
is computed using the ECDSA signature algorithm and the hash function is computed using the ECDSA signature algorithm and the hash function
used is SHA-256 [RFC6234]. Public Key is the most important used is SHA-256 [RFC6234].
parameter in CGA Parameters (sent by 6LN in an NS message). ECC
Public Key could be in uncompressed form or in compressed form where
the first octet of the OCTET STRING is 0x04 and 0x02 or 0x03,
respectively. Point compression can further reduce the key size by
about 32 octets.
NIST P-256 [FIPS186-4] that MUST be supported by all implementations.
To support cryptographic algorithm agility [RFC7696], Edwards-Curve To support cryptographic algorithm agility [RFC7696], Edwards-Curve
Digital Signature Algorithm (EdDSA) curve Ed25519ph (pre-hashing) Digital Signature Algorithm (EdDSA) curve Ed25519ph (pre-hashing)
[RFC8032] can also be used as an alternate to the default NIST P-256 [RFC8032] MAY be supported as an alternate.
[FIPS186-4]. This is indicated by 6LN using the Crypto Type field in
the CIPO option. The document currently only defines two possible
values for the Crypto Type field. A value of 0 indicates that NIST
P-256 is used for the signature operation and SHA-256 as the hash
algorithm. A value of 1 indicates that Ed25519ph is used for the
signature operation and SHA-256 as the hash algorithm. New values
for the Crypto Type maybe defined in the future for new curves.
The Crypto-ID is computed as follows: The Crypto-ID is computed as follows:
1. the modifier is set to a random or pseudo-random 128-bit value 1. An 8-bits modifier is selected, for instance, but not
necessarily, randomly; the modifier enables a device to form
2. the modifier, 9 zero octets and the ECC public key are multiple Crypto-IDs with a single key pair. This may be useful
concatenated from left to right. for privacy reasons in order to avoid the correlation of
addresses based on their Crypto-ID;
3. the SHA-256 algorithm is applied on the concatenation
4. the 112 leftmost bits of the hash value are retained
5. the modifier value, the EUI-64 transformation of the device Link 2. the modifier value and the DER-encoded public key (Section 4.1)
Layer Address and the encoded public key are concatenated from are concatenated from left to right;
left to right
6. Digital signature (NIST P-256 or EdDSA) is executed on the 3. Digital signature (SHA-256 then either NIST P-256 or EdDSA) is
concatenation executed on the concatenation
7. the leftmost bits of the resulting signature are used as the 4. the leftmost bits of the resulting signature are used as the
Crypto-ID. Crypto-ID;
With this specification, only 64 bits are retained, but it could be With this specification, only 64 bits are retained, but it could be
expanded to more bits in the future by increasing the size of the expanded to more bits in the future by increasing the size of the
OUID field. OUID field.
4.2. Updated EARO 4.3. Updated EARO
This specification updates the EARO option as follows: This specification updates the EARO option as follows:
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Status | Reserved | | Type | Length | Status | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |C|T| TID | Registration Lifetime | | Reserved |C|T| TID | Registration Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
+ Owner Unique ID (EUI-64 or equivalent) + + Owner Unique ID (EUI-64 or Crypto-ID) +
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Enhanced Address Registration Option Figure 1: Enhanced Address Registration Option
Type: 33 Type: 33
Length: 8-bit unsigned integer. The length of the option Length: 8-bit unsigned integer. The length of the option
(including the type and length fields) in units of 8 (including the type and length fields) in units of 8
bytes. bytes.
skipping to change at page 7, line 23 skipping to change at page 7, line 37
NS messages. This specification uses values NS messages. This specification uses values
introduced in the update to 6LoWPAN ND introduced in the update to 6LoWPAN ND
[I-D.ietf-6lo-rfc6775-update], such as "Validation [I-D.ietf-6lo-rfc6775-update], such as "Validation
Requested" and "Validation Failed". No additional Requested" and "Validation Failed". No additional
value is defined. value is defined.
Reserved: This field is unused. It MUST be initialized to zero Reserved: This field is unused. It MUST be initialized to zero
by the sender and MUST be ignored by the receiver. by the sender and MUST be ignored by the receiver.
C: This "C" flag is set to indicate that the Owner C: This "C" flag is set to indicate that the Owner
Unique ID field contains a Crypto-ID. Unique ID field contains a Crypto-ID and that the 6LN
MAY be challenged for ownership as specified in this
document.
T and TID: Defined in [I-D.ietf-6lo-rfc6775-update]. T and TID: Defined in [I-D.ietf-6lo-rfc6775-update].
Owner Unique ID: When the "C" flag is set, this field contains a Owner Unique ID: When the "C" flag is set, this field contains a
Crypto-ID. Crypto-ID.
4.3. New Crypto-ID Parameters Option 4.4. Crypto-ID Parameters Option
This specification introduces a new option, the Crypto-ID Parameters This specification defines the Crypto-ID Parameters Option (CIPO), as
Option (CIPO), that carries the proof of ownership of a crypto-ID. a variation of the CGA Option that carries the parameters used to
form a Crypto-ID. In order to provide cryptographic agility, AP-ND
supports two possible signature algorithms, indicated by a Crypto-
Type field. A value of 0 indicates that NIST P-256 is used for the
signature operation and SHA-256 as the hash algorithm. NIST P-256
MUST be supported by all implement A value of 1 indicates that
Ed25519ph is used for the signature operation and SHA-256 as the hash
algorithm.
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Pad Length | Crypto Type | | Type | Length | Pad Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Modifier (16 octets) +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | Crypto-Type | Modifier | Reserved |
+ Subnet Prefix (8 octets) +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| | | |
+ Public Key (variable length) + . .
. Public Key (variable length) .
. .
| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
. . . .
. Padding . . Padding .
. . . .
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Crypto-ID Parameters Option Figure 2: Crypto-ID Parameters Option
Type: CIPO, to be assigned by IANA. Type: 11. This is the same value as the CGA Option, CIPO
is a particular case of the CGA option
Length: The length of the option in units of 8 octets. Length: 8-bit unsigned integer. The length of the option in
units of 8 octets.
Pad Length: The length of the Padding field. Modifier: 8-bit unsigned integer.
Crypto Type: The type of cryptographic algorithm used in Pad Length: 8-bit unsigned integer. The length of the Padding
field.
Crypto-Type: The type of cryptographic algorithm used in
calculation Crypto-ID. Default value of all zeros calculation Crypto-ID. Default value of all zeros
indicate NIST P-256. A value of 1 is assigned for indicate NIST P-256. A value of 1 is assigned for
Ed25519ph. New values may be defined later. Ed25519ph. New values may be defined later.
Modifier: 128 bit random value. Public Key: Public Key of 6LN.
Subnet Prefix: 64 bit subnet prefix.
Public Key: ECC public key of 6LN.
Padding: A variable-length field making the option length a Padding: A variable-length field making the option length a
multiple of 8, containing as many octets as specified multiple of 8, containing as many octets as specified
in the Pad Length field. in the Pad Length field.
5. Protocol Overview 4.5. Nonce Option
5.1. Protocol Scope This document reuses the Nonce Option defined in section 5.3.2. of
SEND [RFC3971] without a change.
4.6. NDP Signature Option
This document reuses the RSA Signature Option (RSAO) defined in
section 5.2. of SEND [RFC3971]. Admittedly, the name is ill-chosen
since the option is extended for non-RSA Signatures and this
specification defines an alias to avoid the confusion.
The description of the operation on the option detailed in section
5.2. of SEND [RFC3971] apply, but for the following changes:
o The 128-bit CGA Message Type tag [RFC3972] for AP-ND is 0x8701
55c8 0cca dd32 6ab7 e415 f148 84d0. (The tag value has been
generated by the editor of this specification on random.org).
o The signature is computed using the hash algorithm and the digital
signature indicated in the Crypto-Type field of the CIPO option
using the private key associated with the public key in the CIPO.
o The alias NDP Signature Option (NDPSO) can be used to refer to the
RSAO when used as described in this specification.
5. Protocol Scope
The scope of the present work is a 6LoWPAN Low Power Lossy Network The scope of the present work is a 6LoWPAN Low Power Lossy Network
(LLN), typically a stub network connected to a larger IP network via (LLN), typically a stub network connected to a larger IP network via
a Border Router called a 6LBR per [RFC6775]. a Border Router called a 6LBR per [RFC6775].
The 6LBR maintains a registration state for all devices in the The 6LBR maintains a registration state for all devices in the
attached LLN, and, in conjunction with the first-hop router (the attached LLN, and, in conjunction with the first-hop router (the
6LR), is in a position to validate uniqueness and grant ownership of 6LR), is in a position to validate uniqueness and grant ownership of
an IPv6 address before it can be used in the LLN. This is a an IPv6 address before it can be used in the LLN. This is a
fundamental difference with a classical network that relies on IPv6 fundamental difference with a classical network that relies on IPv6
skipping to change at page 10, line 5 skipping to change at page 10, line 28
In a mesh network, the 6LR is directly connected to the host device. In a mesh network, the 6LR is directly connected to the host device.
This specification expects that the peer-wise layer-2 security is This specification expects that the peer-wise layer-2 security is
deployed so that all the packets from a particular host are securely deployed so that all the packets from a particular host are securely
identifiable by the 6LR. The 6LR may be multiple hops away from the identifiable by the 6LR. The 6LR may be multiple hops away from the
6LBR. Packets are routed between the 6LR and the 6LBR via other 6LBR. Packets are routed between the 6LR and the 6LBR via other
6LRs. This specification expects that a chain of trust is 6LRs. This specification expects that a chain of trust is
established so that a packet that was validated by the first 6LR can established so that a packet that was validated by the first 6LR can
be safely routed by the next 6LRs to the 6LBR. be safely routed by the next 6LRs to the 6LBR.
5.2. Protocol Flows 6. Protocol Flows
Figure 4 illustrates a registration flow all the way to a 6LowPAN The 6LR/6LBR ensures first-come/first-serve by storing the EARO
Backbone Router (6BBR). information including the Crypto-ID correlated to the node being
registered. The node is free to claim any address it likes as long
as it is the first to make such a claim. After a successful
registration, the node becomes the owner of the registered address
and the address is bound to the Crypto-ID in the 6LR/6LBR registry.
This specification enables to verify the ownership of the binding at
any time assuming that the "C" flag is set. If it is not set, then
the verification methods presented in this specification cannot be
applied. The verification prevents other nodes from stealing the
address and trying to attract traffic for that address or use it as
their source address.
A node may use multiple IPv6 addresses at the same time. The node
may use a same Crypto-ID, or multiple crypto-IDs derived from a same
key pair, to protect multiple IPv6 addresses. The separation of the
address and the cryptographic material avoids the constrained device
to compute multiple keys for multiple addresses. The registration
process allows the node to bind all of its addresses to the same
Crypto-ID.
6.1. First Exchange with a 6LR
A 6LN registers to a 6LR that is one hop away from it with the "C"
flag set in the EARO, indicating that the Owner Unique ID field
contains a Crypto-ID. The on-link (local) protocol interactions are
shown in Figure 4 If the 6LR does not have a state with the 6LN that
is consistent with the NS(EARO), then it replies with a challenge NA
(EARO, status=Validation Requested) that contains a Nonce Option.
The Nonce option MUST contain a Nonce value that was never used with
this device.
The 6LN replies to the challenge with a proof-of-ownership NS(EARO)
that includes the echoed Nonce option, the CIPO with all the
parameters that where used to build EARO with a Crypto-ID, and as the
last option the NDPSO with the signature. The information associated
to a crypto-ID is passed to and stored by the 6LR on the first NS
exchange where it appears. The 6LR SHOULD store the CIPO information
associated with the crypto-ID so it can be used for more than one
address.
6LN 6LR
| |
|<------------------------- RA -------------------------|
| | ^
|---------------- NS with EARO (Crypto-ID) ------------>| |
| | option
|<- NA with EARO (status=Validation Requested), Nonce --| |
| | v
|-------- NS with EARO, CIPO, Nonce and NDPSO --------->|
| |
|<------------------- NA with EARO ---------------------|
| |
...
| |
|--------------- NS with EARO (Crypto-ID) ------------->|
| |
|<------------------- NA with EARO ---------------------|
| |
...
| |
|--------------- NS with EARO (Crypto-ID) ------------->|
| |
|<------------------- NA with EARO ---------------------|
| |
Figure 4: On-link Protocol Operation
The steps for the registration to the 6LR are as follows:
o Upon the first exchange with a 6LR, a 6LN may be challenged and
have to produce the proof of ownership of the Crypto-ID. However,
it is not expected that the proof is needed again in the periodic
refresher registrations for that address, or when registering
other addresses with the same OUID. When a 6LR receives a
NS(EARO) registration with a new Crypto-ID as a OUID, it SHOULD
challenge by responding with a NA(EARO) with a status of
"Validation Requested". This process of validation MAY be skipped
in networks where there is no mobility.
o The challenge MUST also be triggered in the case of a registration
for which the Source Link-Layer Address is not consistent with a
state that already exists either at the 6LR or the 6LBR. In the
latter case, the 6LBR returns a status of "Validation Requested"
in the DAR/DAC exchange, which is echoed by the 6LR in the NA
(EARO) back to the registering node. This flow should not alter a
preexisting state in the 6LR or the 6LBR.
o Upon receiving a NA(EARO) with a status of "Validation Requested",
the registering node SHOULD retry its registration with a Crypto-
ID Parameters Option (CIPO) Section 4.4 that contains all the
necessary material for building the Crypto-ID, the Nonce and the
NDP signature Section 4.6 options that prove its ownership of the
Crypto-ID.
o In order to validate the ownership, the 6LR performs the same
steps as the 6LN and rebuilds the Crypto-ID based on the
parameters in the CIPO. If the result is different then the
validation fails. Else, the 6LR checks the signature in the NDPSO
using the public key in the CIPO. If it is correct then the
validation passes, else it fails.
o If the 6LR fails to validate the signed NS(EARO), it responds with
a status of "Validation Failed". After receiving a NA(EARO) with
a status of "Validation Failed", the registering node SHOULD try
an alternate Signature Algorithm and Crypto-ID. In any case, it
MUST NOT use this Crypto-ID for registering with that 6LR again.
6.2. Multihop Operation
In a multihop 6LoWPAN, the registration with Crypto-ID is propagated
to 6LBR as described in Section 6.2. If a chain of trust is present
between the 6LR and the 6LBR, then there is no need to propagate the
proof of ownership to the 6LBR. All the 6LBR needs to know is that
this particular OUID is randomly generated, so as to enforce that any
update via a different 6LR is also random.
A new device that joins the network auto-configures an address and A new device that joins the network auto-configures an address and
performs an initial registration to an on-link 6LR with an NS message performs an initial registration to an on-link 6LR with an NS message
that carries an Address Registration Option (EARO) [RFC6775]. The that carries an Address Registration Option (EARO) [RFC6775]. The
6LR validates the address with the central 6LBR using a DAR/DAC 6LR validates the address with the central 6LBR using a DAR/DAC
exchange, and the 6LR confirms (or denies) the address ownership with exchange, and the 6LR confirms (or denies) the address ownership with
an NA message that also carries an Address Registration Option. an NA message that also carries an Address Registration Option.
In a multihop 6LoWPAN, the registration with Crypto-ID is propagated Figure 5 illustrates a registration flow all the way to a 6LowPAN
to 6LBR as described in Section 5.3. If a chain of trust is present Backbone Router (6BBR).
between the 6LR and the 6LBR, then there is no need to propagate the
proof of ownership to the 6LBR. All the 6LBR needs to know is that
this particular OUID is randomly generated, so as to enforce that any
update via a different 6LR is also random.
6LN 6LR 6LBR 6BBR 6LN 6LR 6LBR 6BBR
| | | | | | | |
| NS(EARO) | | | | NS(EARO) | | |
|--------------->| | | |--------------->| | |
| | Extended DAR | | | | Extended DAR | |
| |-------------->| | | |-------------->| |
| | | | | | | |
| | | proxy NS(EARO) | | | | proxy NS(EARO) |
| | |--------------->| | | |--------------->|
skipping to change at page 10, line 46 skipping to change at page 13, line 37
| | | | <wait> | | | | <wait>
| | | | | | | |
| | | proxy NA(EARO) | | | | proxy NA(EARO) |
| | |<---------------| | | |<---------------|
| | Extended DAC | | | | Extended DAC | |
| |<--------------| | | |<--------------| |
| NA(EARO) | | | | NA(EARO) | | |
|<---------------| | | |<---------------| | |
| | | | | | | |
Figure 4: (Re-)Registration Flow Figure 5: (Re-)Registration Flow
On-link (local) protocol interactions are shown in Figure 5. Crypto-
ID and ARO are passed to and stored by the 6LR on the first NS and
not sent again in the next NS. The operation starts with 6LR sending
a Router Advertisement (RA) message to 6LN.
The 6LR/6LBR ensures first-come/first-serve by storing the ARO and
the Crypto-ID correlated to the node being registered. The node is
free to claim any address it likes as long as it is the first to make
such a claim. After a successful registration, the node becomes the
owner of the registered address and the address is bound to the
Crypto-ID in the 6LR/6LBR registry. This binding can be verified
later, which prevents other nodes from stealing the address and
trying to attract traffic for that address or use it as their source
address.
A node may use multiple IPv6 addresses at the same time. The node
may use the same Crypto-ID to protect multiple IPv6 addresses. The
separation of the address and the Crypto-ID avoids the constrained
device to compute multiple keys for multiple addresses. The
registration process allows the node to bind all of its addresses to
the same Crypto-ID.
6LN 6LR
| |
|<------------------- RA --------------------------|
| |
|----------- NS with ARO and Crypto-ID ----------->|
| |
|<---------- NA with ARO (status=proof requested) -|
| |
|----------- NS with ARO and Crypto-ID ----------->|
| |
|<---------------- NA with ARO --------------------|
| |
... ...
| |
|------------ NS with ARO and Crypto-ID ---------->|
| |
| |
|<---------------- NA with ARO --------------------|
... ...
| |
|----------- NS with ARO and Crypto-ID ----------->|
| |
| |
|<---------------- NA with ARO --------------------|
Figure 5: On-link Protocol Operation
5.3. Multihop Operation
In a multihop 6LoWPAN, a 6LBR sends RAs with prefixes downstream and In a multihop 6LoWPAN, a 6LBR sends RAs with prefixes downstream and
the 6LR receives and relays them to the nodes. 6LR and 6LBR the 6LR receives and relays them to the nodes. 6LR and 6LBR
communicate using ICMPv6 Duplicate Address Request (DAR) and communicate using ICMPv6 Duplicate Address Request (DAR) and
Duplicate Address Confirmation (DAC) messages. The DAR and DAC use Duplicate Address Confirmation (DAC) messages. The DAR and DAC use
the same message format as NS and NA, but have different ICMPv6 type the same message format as NS and NA, but have different ICMPv6 type
values. values.
In ND-PAR we extend DAR/DAC messages to carry cryptographically In AP-ND we extend DAR/DAC messages to carry cryptographically
generated OUID. In a multihop 6LoWPAN, the node exchanges the generated OUID. In a multihop 6LoWPAN, the node exchanges the
messages shown in Figure 4. The 6LBR must identify who owns an messages shown in Figure 5. The 6LBR must identify who owns an
address (EUI-64) to defend it, if there is an attacker on another address (EUI-64) to defend it, if there is an attacker on another
6LR. Because of this the content that the source signs and the 6LR.
signature needs to be propagated to the 6LBR in the DAR message. For
this purpose the DAR message sent by 6LR to 6LBR MUST contain the
CIPO option. The DAR message also contains ARO.
Occasionally, a 6LR might miss the node's OUID (that it received in Occasionally, a 6LR might miss the node's OUID (that it received in
ARO). 6LR should be able to ask for it again. This is done by ARO). 6LR should be able to ask for it again. This is done by
restarting the exchanges shown in Figure 5. The result enables 6LR restarting the exchanges shown in Figure 4. The result enables 6LR
to refresh the information that was lost. The 6LR MUST send DAR to refresh the information that was lost. The 6LR MUST send DAR
message with ARO to 6LBR. The 6LBR replies with a DAC message with message with ARO to 6LBR. The 6LBR replies with a DAC message with
the information copied from the DAR, and the Status field is set to the information copied from the DAR, and the Status field is set to
zero. With this exchange, the 6LBR can (re)validate and store the zero. With this exchange, the 6LBR can (re)validate and store the
information to make sure that the 6LR is not a fake. information to make sure that the 6LR is not a fake.
In some cases, the 6LBR may use a DAC message to solicit a Crypto-ID In some cases, the 6LBR may use a DAC message to solicit a Crypto-ID
from a 6LR and also requests 6LR to verify the EUI-64 6LR received from a 6LR and also requests 6LR to verify the EUI-64 6LR received
from 6LN. This may happen when a 6LN node is compromised and a fake from 6LN. This may happen when a 6LN node is compromised and a fake
node is sending the Crypto-ID as if it is the node's EUI-64. Note node is sending the Crypto-ID as if it is the node's EUI-64. Note
that the detection in this case can only be done by 6LBR not by 6LR. that the detection in this case can only be done by 6LBR not by 6LR.
6. Security Considerations 7. Security Considerations
7.1. Inheriting from RTC 3971
The observations regarding the threats to the local network in The observations regarding the threats to the local network in
[RFC3971] also apply to this specification. [RFC3971] also apply to this specification. Considering RFC3971
security section subsection by subsection:
Neighbor Solicitation/Advertisement Spoofing Threats in section
9.2.1 of RFC3971 apply. AP-ND counters the threats on NS(EARO)
messages by requiring that the NDP Signature and CIPO options be
present in these solicitations.
Neighbor Unreachability Detection Failure With RFC6775, a NUD can
still be used by the endpoint to assess the liveliness of a
device. The NUD request may be protected by SEND in which case
the provision in section 92.2. of RFC 3972 applies. The response
to the NUD may be proxied by a backbone router only if it has a
fresh registration state for it. The registration being protected
by this specification, the proxied NUD response provides a
truthful information on the original owner of the address but it
cannot be proven using SEND. If the NUD response is not proxied,
the 6LR will pass the lookup to the end device which will respond
with a traditional NA. If the 6LR does not have a cache entry
associated for the device, it can issue a NA with EARO
(status=Validation Requested) upon the NA from the device, which
will trigger a NS that will recreate and revalidate the ND cache
entry.
Duplicate Address Detection DoS Attack Inside the LLN, Duplicate
Addresses are sorted out using the OUID, which differentiates it
from a movement. DAD coming from the backbone are not forwarded
over the LLN so the LLN is protected by the backbone routers.
Over the backbone, the EARO option is present in NS/NA messages.
This protects against misinterpreting a movement for a
duplication, and enables to decide which backbone router has the
freshest registration and thus most possibly the device attached
to it. But this specification does not guarantee that the
backbone router claiming an address over the backbone is not an
attacker.
Router Solicitation and Advertisement Attacks This specification
does not change the protection of RS and RA which can still be
protected by SEND.
Replay Attacks A Nonce given by the 6LR in the NA with EARO
(status=Validation Requested) and echoed in the signed NS
guarantees against replay attacks of the NS(EARO). The NA(EARO)
is not protected and can be forged by a rogue node that is not the
6LR in order to force the 6LN to rebuild a NS(EARO) with the proof
of ownership, but that rogue node must have access to the L2 radio
network next to the 6LN to perform the attack.
Neighbor Discovery DoS Attack A rogue node that managed to access
the L2 network may form many addresses and register them using AP-
ND. The perimeter of the attack os all the 6LRs in range of the
attacker. The 6LR must protect itself against overflows and
reject excessive registration with a status 2 "Neighbor Cache
Full". This effectively blocks another (honest) 6LN from
registering to the same 6LR, but the 6LN may register to other
6LRs that are in its range but not in that of the rogue.
7.2. Related to 6LoWPAN ND
The threats discussed in 6LoWPAN ND [RFC6775] and its update The threats discussed in 6LoWPAN ND [RFC6775] and its update
[I-D.ietf-6lo-rfc6775-update] also apply here. Compared with SeND, [I-D.ietf-6lo-rfc6775-update] also apply here. Compared with SeND,
this specification saves about 1Kbyte in every NS/NA message. Also, this specification saves about 1Kbyte in every NS/NA message. Also,
this specification separates the cryptographic identifier from the this specification separates the cryptographic identifier from the
registered IPv6 address so that a node can have more than one IPv6 registered IPv6 address so that a node can have more than one IPv6
address protected by the same cryptographic identifier. SeND forces address protected by the same cryptographic identifier. SeND forces
the IPv6 address to be cryptographic since it integrates the CGA as the IPv6 address to be cryptographic since it integrates the CGA as
the IID in the IPv6 address. This specification frees the device to the IID in the IPv6 address. This specification frees the device to
form its addresses in any fashion, so as to enable the classical form its addresses in any fashion, so as to enable the classical
6LoWPAN compression which derives IPv6 addresses from Layer-2 6LoWPAN compression which derives IPv6 addresses from Layer-2
addresses, as well as privacy addresses. The threats discussed in addresses, as well as privacy addresses. The threats discussed in
Section 9.2 of [RFC3971] are countered by the protocol described in Section 9.2 of [RFC3971] are countered by the protocol described in
this document as well. this document as well.
7.3. OUID Collisions
Collisions of Owner Unique Interface IDentifier (OUID) (which is the Collisions of Owner Unique Interface IDentifier (OUID) (which is the
Crypto-ID in this specification) is a possibility that needs to be Crypto-ID in this specification) is a possibility that needs to be
considered. The formula for calculating the probability of a considered. The formula for calculating the probability of a
collision is 1 - e^{-k^2/(2n)} where n is the maximum population size collision is 1 - e^{-k^2/(2n)} where n is the maximum population size
(2^64 here, 1.84E19) and K is the actual population (number of (2^64 here, 1.84E19) and K is the actual population (number of
nodes). If the Crypto-ID is 64-bit long, then the chance of finding nodes). If the Crypto-ID is 64-bit long, then the chance of finding
a collision is 0.01% when the network contains 66 million nodes. It a collision is 0.01% when the network contains 66 million nodes. It
is important to note that the collision is only relevant when this is important to note that the collision is only relevant when this
happens within one stub network (6LBR). A collision of Crypto-ID is happens within one stub network (6LBR). A collision of Crypto-ID is
a rare event. In the case of a collision, an attacker may be able to a rare event. In the case of a collision, an attacker may be able to
claim the registered address of an another legitimate node. However claim the registered address of an another legitimate node. However
for this to happen, the attacker would also need to know the address for this to happen, the attacker would also need to know the address
which was registered by the legitimate node. This registered address which was registered by the legitimate node. This registered address
is however never broadcasted on the network and therefore it provides is however never broadcasted on the network and therefore it provides
an additional entropy of 64-bits that an attacker must correctly an additional entropy of 64-bits that an attacker must correctly
guess. To prevent such a scenario, it is RECOMMENDED that nodes guess. To prevent such a scenario, it is RECOMMENDED that nodes
derive the address being registered independently of the OUID. derive the address being registered independently of the OUID.
7. IANA considerations 8. IANA considerations
IANA is requested to assign two new option type values for the CIPO 8.1. CGA Message Type
under the subregistry "IPv6 Neighbor Discovery Option Formats".
7.1. Crypto Type Registry This document defines a new 128-bit value under the CGA Message Type
[RFC3972] namespace, 0x8701 55c8 0cca dd32 6ab7 e415 f148 84d0.
The following Crypto Type values are defined in this document: 8.2. Crypto-Type Subregistry
+-------------------+--------------------------------------------+ IANA is requested to create a new subregistry "Crypto-Type
| Crypto Type value | Algorithms | Subregistry" in the "Internet Control Message Protocol version 6
+-------------------+--------------------------------------------+ (ICMPv6) Parameters". The registry is indexed by an integer 0..255
| 0 | NIST P-256 [FIPS186-4] , SHA-256 [RFC6234] | and contains a Signature Algorithm and a Hash Function as shown in
| 1 | Ed25519ph [RFC8032], SHA-256 [RFC6234] | Table 1. The following Crypto-Type values are defined in this
+-------------------+--------------------------------------------+ document:
Table 1: Crypto Types +--------------+-----------------+---------------+------------------+
| Crypto-Type | Signature | Hash Function | Defining |
| value | Algorithm | | Specification |
+--------------+-----------------+---------------+------------------+
| 0 | NIST P-256 | SHA-256 | RFC THIS |
| | [FIPS186-4] | [RFC6234] | |
| 1 | Ed25519ph | SHA-256 | RFC THIS |
| | [RFC8032] | [RFC6234] | |
+--------------+-----------------+---------------+------------------+
Assignment of new values for new Crypto Type MUST be done through Table 1: Crypto-Types
Assignment of new values for new Crypto-Type MUST be done through
IANA with "Specification Required" and "IESG Approval" as defined in IANA with "Specification Required" and "IESG Approval" as defined in
[RFC8126]. [RFC8126].
8. Acknowledgements 9. Acknowledgments
Many thanks to Charlie Perkins for his in-depth review and Many thanks to Charlie Perkins for his in-depth review and
constructive suggestions. We are also especially grateful to Rene constructive suggestions. We are also especially grateful to Rene
Struik and Robert Moskowitz for their comments that lead to many Struik and Robert Moskowitz for their comments that lead to many
improvements to this document, in particular WRT ECC computation and improvements to this document, in particular WRT ECC computation and
references. references.
9. References 10. References
9.1. Normative References 10.1. Normative References
[FIPS-186-4]
FIPS 186-4, "Digital Signature Standard (DSS), Federal
Information Processing Standards Publication 186-4", US
Department of Commerce/National Institute of Standards and
Technology Gaithersburg, MD, July 2013.
[I-D.ietf-6lo-rfc6775-update] [I-D.ietf-6lo-rfc6775-update]
Thubert, P., Nordmark, E., Chakrabarti, S., and C. Thubert, P., Nordmark, E., Chakrabarti, S., and C.
Perkins, "An Update to 6LoWPAN ND", draft-ietf-6lo- Perkins, "An Update to 6LoWPAN ND", draft-ietf-6lo-
rfc6775-update-10 (work in progress), October 2017. rfc6775-update-11 (work in progress), December 2017.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3279] Bassham, L., Polk, W., and R. Housley, "Algorithms and
Identifiers for the Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 3279, DOI 10.17487/RFC3279, April
2002, <https://www.rfc-editor.org/info/rfc3279>.
[RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander,
"SEcure Neighbor Discovery (SEND)", RFC 3971,
DOI 10.17487/RFC3971, March 2005,
<https://www.rfc-editor.org/info/rfc3971>.
[RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)",
RFC 3972, DOI 10.17487/RFC3972, March 2005,
<https://www.rfc-editor.org/info/rfc3972>.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, DOI 10.17487/RFC4291, February Architecture", RFC 4291, DOI 10.17487/RFC4291, February
2006, <https://www.rfc-editor.org/info/rfc4291>. 2006, <https://www.rfc-editor.org/info/rfc4291>.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007, DOI 10.17487/RFC4861, September 2007,
<https://www.rfc-editor.org/info/rfc4861>. <https://www.rfc-editor.org/info/rfc4861>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007, DOI 10.17487/RFC4862, September 2007,
<https://www.rfc-editor.org/info/rfc4862>. <https://www.rfc-editor.org/info/rfc4862>.
[RFC5758] Dang, Q., Santesson, S., Moriarty, K., Brown, D., and T.
Polk, "Internet X.509 Public Key Infrastructure:
Additional Algorithms and Identifiers for DSA and ECDSA",
RFC 5758, DOI 10.17487/RFC5758, January 2010,
<https://www.rfc-editor.org/info/rfc5758>.
[RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
Bormann, "Neighbor Discovery Optimization for IPv6 over Bormann, "Neighbor Discovery Optimization for IPv6 over
Low-Power Wireless Personal Area Networks (6LoWPANs)", Low-Power Wireless Personal Area Networks (6LoWPANs)",
RFC 6775, DOI 10.17487/RFC6775, November 2012, RFC 6775, DOI 10.17487/RFC6775, November 2012,
<https://www.rfc-editor.org/info/rfc6775>. <https://www.rfc-editor.org/info/rfc6775>.
9.2. Informative references 10.2. Informative references
[FIPS186-4] [FIPS186-4]
"FIPS Publication 186-4: Digital Signature Standard", July "FIPS Publication 186-4: Digital Signature Standard", July
2013, <http://nvlpubs.nist.gov/nistpubs/FIPS/ 2013, <http://nvlpubs.nist.gov/nistpubs/FIPS/
NIST.FIPS.186-4.pdf>. NIST.FIPS.186-4.pdf>.
[I-D.ietf-6lo-backbone-router] [I-D.ietf-6lo-backbone-router]
Thubert, P., "IPv6 Backbone Router", draft-ietf-6lo- Thubert, P., "IPv6 Backbone Router", draft-ietf-6lo-
backbone-router-04 (work in progress), July 2017. backbone-router-05 (work in progress), January 2018.
[I-D.struik-lwip-curve-representations] [I-D.struik-lwig-curve-representations]
Struik, R., "Alternative Elliptic Curve Representations", Struik, R., "Alternative Elliptic Curve Representations",
draft-struik-lwip-curve-representations-00 (work in draft-struik-lwig-curve-representations-00 (work in
progress), October 2017. progress), November 2017.
[RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander,
"SEcure Neighbor Discovery (SEND)", RFC 3971,
DOI 10.17487/RFC3971, March 2005,
<https://www.rfc-editor.org/info/rfc3971>.
[RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)",
RFC 3972, DOI 10.17487/RFC3972, March 2005,
<https://www.rfc-editor.org/info/rfc3972>.
[RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6 [RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6
over Low-Power Wireless Personal Area Networks (6LoWPANs): over Low-Power Wireless Personal Area Networks (6LoWPANs):
Overview, Assumptions, Problem Statement, and Goals", Overview, Assumptions, Problem Statement, and Goals",
RFC 4919, DOI 10.17487/RFC4919, August 2007, RFC 4919, DOI 10.17487/RFC4919, August 2007,
<https://www.rfc-editor.org/info/rfc4919>. <https://www.rfc-editor.org/info/rfc4919>.
[RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, [RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
"Transmission of IPv6 Packets over IEEE 802.15.4 "Transmission of IPv6 Packets over IEEE 802.15.4
Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007, Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007,
skipping to change at page 17, line 27 skipping to change at page 21, line 7
o The Address Registration Option used in the ND registration SHOULD o The Address Registration Option used in the ND registration SHOULD
be extended to carry the relevant forms of Unique Interface be extended to carry the relevant forms of Unique Interface
IDentifier. IDentifier.
o The Neighbour Discovery should specify the formation of a site- o The Neighbour Discovery should specify the formation of a site-
local address that follows the security recommendations from local address that follows the security recommendations from
[RFC7217]. [RFC7217].
Authors' Addresses Authors' Addresses
Behcet Sarikaya Pascal Thubert (editor)
Plano, TX
USA
Email: sarikaya@ieee.org
Pascal Thubert
Cisco Systems, Inc Cisco Systems, Inc
Building D Building D
45 Allee des Ormes - BP1200 45 Allee des Ormes - BP1200
MOUGINS - Sophia Antipolis 06254 MOUGINS - Sophia Antipolis 06254
FRANCE FRANCE
Phone: +33 497 23 26 34 Phone: +33 497 23 26 34
Email: pthubert@cisco.com Email: pthubert@cisco.com
Behcet Sarikaya
Plano, TX
USA
Email: sarikaya@ieee.org
Mohit Sethi Mohit Sethi
Ericsson Ericsson
Hirsalantie Hirsalantie
Jorvas 02420 Jorvas 02420
Email: mohit@piuha.net Email: mohit@piuha.net
 End of changes. 74 change blocks. 
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