draft-ietf-6lo-ap-nd-11.txt   draft-ietf-6lo-ap-nd-12.txt 
6lo P. Thubert, Ed. 6lo P. Thubert, Ed.
Internet-Draft Cisco Internet-Draft Cisco
Updates: 8505 (if approved) B. Sarikaya Updates: 8505 (if approved) B. Sarikaya
Intended status: Standards Track Intended status: Standards Track
Expires: August 29, 2019 M. Sethi Expires: October 12, 2019 M. Sethi
Ericsson Ericsson
R. Struik R. Struik
Struik Security Consultancy Struik Security Consultancy
February 25, 2019 April 10, 2019
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-11 draft-ietf-6lo-ap-nd-12
Abstract Abstract
This document specifies an extension to 6LoWPAN Neighbor Discovery This document specifies an extension to 6LoWPAN Neighbor Discovery
(ND) protocol defined in RFC6775 and updated in RFC8505. The new (ND) protocol defined in RFC6775 and updated in RFC8505. The new
extension is called Address Protected Neighbor Discovery (AP-ND) and extension is called Address Protected Neighbor Discovery (AP-ND) and
it protects the owner of an address against address theft and it protects the owner of an address against address theft and
impersonation attacks in a low-power and lossy network (LLN). Nodes impersonation attacks in a low-power and lossy network (LLN). Nodes
supporting this extension compute a cryptographic identifier (Crypto- supporting this extension compute a cryptographic identifier (Crypto-
ID) and use it with one or more of their Registered Addresses. The ID) and use it with one or more of their Registered Addresses. The
skipping to change at page 1, line 47 skipping to change at page 1, line 47
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
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
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 August 29, 2019. This Internet-Draft will expire on October 12, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 32 skipping to change at page 2, line 32
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. BCP 14 . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. BCP 14 . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. References . . . . . . . . . . . . . . . . . . . . . . . 4 2.2. References . . . . . . . . . . . . . . . . . . . . . . . 4
2.3. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 5 2.3. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 5
3. Updating RFC 8505 . . . . . . . . . . . . . . . . . . . . . . 6 3. Updating RFC 8505 . . . . . . . . . . . . . . . . . . . . . . 6
4. New Fields and Options . . . . . . . . . . . . . . . . . . . 6 4. New Fields and Options . . . . . . . . . . . . . . . . . . . 6
4.1. New Crypto-ID . . . . . . . . . . . . . . . . . . . . . . 6 4.1. New Crypto-ID . . . . . . . . . . . . . . . . . . . . . . 6
4.2. Updated EARO . . . . . . . . . . . . . . . . . . . . . . 7 4.2. Updated EARO . . . . . . . . . . . . . . . . . . . . . . 7
4.3. Crypto-ID Parameters Option . . . . . . . . . . . . . . . 8 4.3. Crypto-ID Parameters Option . . . . . . . . . . . . . . . 8
4.4. Nonce Option . . . . . . . . . . . . . . . . . . . . . . 9 4.4. NDP Signature Option . . . . . . . . . . . . . . . . . . 9
4.5. NDP Signature Option . . . . . . . . . . . . . . . . . . 9 5. Protocol Scope . . . . . . . . . . . . . . . . . . . . . . . 11
5. Protocol Scope . . . . . . . . . . . . . . . . . . . . . . . 10
6. Protocol Flows . . . . . . . . . . . . . . . . . . . . . . . 11 6. Protocol Flows . . . . . . . . . . . . . . . . . . . . . . . 11
6.1. First Exchange with a 6LR . . . . . . . . . . . . . . . . 11 6.1. First Exchange with a 6LR . . . . . . . . . . . . . . . . 12
6.2. NDPSO generation and verification . . . . . . . . . . . . 13 6.2. NDPSO generation and verification . . . . . . . . . . . . 14
6.3. Multihop Operation . . . . . . . . . . . . . . . . . . . 14 6.3. Multihop Operation . . . . . . . . . . . . . . . . . . . 16
7. Security Considerations . . . . . . . . . . . . . . . . . . . 16 7. Security Considerations . . . . . . . . . . . . . . . . . . . 17
7.1. Inheriting from RFC 3971 . . . . . . . . . . . . . . . . 16 7.1. Inheriting from RFC 3971 . . . . . . . . . . . . . . . . 17
7.2. Related to 6LoWPAN ND . . . . . . . . . . . . . . . . . . 17 7.2. Related to 6LoWPAN ND . . . . . . . . . . . . . . . . . . 18
7.3. ROVR Collisions . . . . . . . . . . . . . . . . . . . . . 17 7.3. ROVR Collisions . . . . . . . . . . . . . . . . . . . . . 18
7.4. Implementation Attacks . . . . . . . . . . . . . . . . . 17 7.4. Implementation Attacks . . . . . . . . . . . . . . . . . 19
7.5. Cross-Protocol Attacks . . . . . . . . . . . . . . . . . 18 7.5. Cross-Protocol Attacks . . . . . . . . . . . . . . . . . 19
8. IANA considerations . . . . . . . . . . . . . . . . . . . . . 18 8. IANA considerations . . . . . . . . . . . . . . . . . . . . . 19
8.1. CGA Message Type . . . . . . . . . . . . . . . . . . . . 18 8.1. CGA Message Type . . . . . . . . . . . . . . . . . . . . 19
8.2. Crypto-Type Subregistry . . . . . . . . . . . . . . . . . 18 8.2. IPv6 ND option types . . . . . . . . . . . . . . . . . . 19
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19 8.3. Crypto-Type Subregistry . . . . . . . . . . . . . . . . . 20
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 19 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 21
10.1. Normative References . . . . . . . . . . . . . . . . . . 19 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 21
10.2. Informative references . . . . . . . . . . . . . . . . . 20 10.1. Normative References . . . . . . . . . . . . . . . . . . 21
Appendix A. Requirements Addressed in this Document . . . . . . 22 10.2. Informative references . . . . . . . . . . . . . . . . . 22
Appendix B. Representation Conventions . . . . . . . . . . . . . 22 Appendix A. Requirements Addressed in this Document . . . . . . 24
B.1. Signature Schemes . . . . . . . . . . . . . . . . . . . . 22 Appendix B. Representation Conventions . . . . . . . . . . . . . 24
B.2. Integer Representation for ECDSA signatures . . . . . . . 23 B.1. Signature Schemes . . . . . . . . . . . . . . . . . . . . 24
B.3. Alternative Representations of Curve25519 . . . . . . . . 23 B.2. Integer Representation for ECDSA signatures . . . . . . . 25
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25 B.3. Alternative Representations of Curve25519 . . . . . . . . 25
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27
1. Introduction 1. Introduction
Neighbor Discovery Optimizations for 6LoWPAN networks [RFC6775] Neighbor Discovery Optimizations for 6LoWPAN networks [RFC6775]
(6LoWPAN ND) adapts the original IPv6 neighbor discovery (NDv6) (6LoWPAN ND) adapts the original IPv6 neighbor discovery (NDv6)
protocols defined in [RFC4861] and [RFC4862] for constrained low- protocols defined in [RFC4861] and [RFC4862] for constrained low-
power and lossy network (LLN). In particular, 6LoWPAN ND introduces power and lossy network (LLN). In particular, 6LoWPAN ND introduces
a unicast host address registration mechanism that reduces the use of a unicast host address registration mechanism that reduces the use of
multicast. 6LoWPAN ND defines a new Address Registration Option (ARO) multicast. 6LoWPAN ND defines a new Address Registration Option (ARO)
that is carried in the unicast Neighbor Solicitation (NS) and that is carried in the unicast Neighbor Solicitation (NS) and
skipping to change at page 6, line 9 skipping to change at page 6, line 9
RS: Router Solicitation RS: Router Solicitation
RSAO: RSA Signature Option RSAO: RSA Signature Option
TID: Transaction ID TID: Transaction ID
3. Updating RFC 8505 3. Updating RFC 8505
This specification introduces a new token called a cryptographic This specification introduces a new token called a cryptographic
identifier (Crypto-ID) that is used to prove indirectly the ownership identifier (Crypto-ID) that is used to prove indirectly the ownership
of an address that is being registered by means of [RFC8505]. of an address that is being registered by means of [RFC8505]. The
Crypto-ID is derived from a cryptographic public key and additional
parameters. The proof requires the support of Elliptic Curve
Cryptography (ECC) and that of a hash function as detailed in
Section 6.2. To enable the verification of the proof, the
registering node needs to supply certain parameters including a nonce
and a signature that will demonstrate that the node has the private-
key corresponding to the public-key used to build the Crypto-ID.
In order to prove its ownership of a Crypto-ID, the registering node The elliptic curves and the hash functions that can be used with this
needs to supply certain parameters including a nonce and a signature specification are listed in Table 2 in Section 8.3. The signature
that will prove that the node has the private-key corresponding to scheme that specifies which combination is used is signaled by a
the public-key used to build the Crypto-ID. This specification adds Crypto-Type in the CIPO (see Section 4.3).
the capability to carry new options in the NS(EARO) and the NA(EARO).
The NS(EARO) carries a variation of the CGA Option (Section 4.3), a
Nonce option and a variation of the RSA Signature option
(Section 4.5) in the NS(EARO). The NA(EARO) carries a Nonce option.
4. New Fields and Options The NS(EARO) is extended to transport a new Crypto-ID Parameters
Option (CIPO, see Section 4.3) that contains the parameters that are
necessary for the proof, a Nonce option ([RFC3971]) and a NDP
Signature option (Section 4.4). The NA(EARO) is modified to enable a
challenge and transport a Nonce option as well.
In order to avoid the need for new ND option types, this 4. New Fields and Options
specification reuses and extends options defined in SEND [RFC3971]
and 6LoWPAN ND [RFC6775] [RFC8505]. 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 this document. The presence of the EARO option in the NS/NA
messages indicates that the options are to be processed as specified
in this document, and not as defined in SEND [RFC3971].
4.1. New Crypto-ID 4.1. New Crypto-ID
The Crypto-ID can be used as a replacement to the MAC address in the The Crypto-ID is transported in the ROVR field of the EARO option and
ROVR field of the EARO option and the EDAR message, and is associated the EDAR message, and is associated with the Registered Address at
with the Registered Address. The ownership of a Crypto-ID can be the 6LR and the 6LBR. The ownership of a Crypto-ID can be
demonstrated by cryptographic mechanisms, and by association, the demonstrated by cryptographic mechanisms, and by association, the
ownership of the Registered Address can be acertained. A node in ownership of the Registered Address can be acertained.
possession of the necessary cryptographic primitives SHOULD use
Crypto-ID by default as ROVR in its registrations. Whether a ROVR is
a Crypto-ID is indicated by a new "C" flag in the NS(EARO) message.
The computation of the Crypto-ID requires the support of Elliptic A node in possession of the necessary cryptographic primitives SHOULD
Curve Cryptography (ECC) and that of a hash function as detailed in use Crypto-ID by default as ROVR in its registrations. Whether a
Section 6.2. The elliptic curves and the hash functions that can be ROVR is a Crypto-ID is indicated by a new "C" flag in the NS(EARO)
used with this specification are listed in Table 1 in Section 8.2. message.
The signature scheme that specifies which combination is used is
signaled by a Crypto-Type in a new Crypto-ID Parameters Option (see The Crypto-ID is derived from the public key and a modifier as
Section 4.3). follows:
1. The hash function indicated by the Crypto-Type is applied to the
CIPO. Note that all the reserved and padding bits MUST be set to
zero.
2. The leftmost bits of the resulting hash, up to the size of the
ROVR field, are used as the Crypto-ID.
4.2. Updated EARO 4.2. 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 | Opaque | | Type | Length | Status | Opaque |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 8, line 7 skipping to change at page 8, line 7
Registration Ownership Verifier (ROVR): When the "C" flag is set, Registration Ownership Verifier (ROVR): When the "C" flag is set,
this field contains a Crypto-ID. this field contains a Crypto-ID.
This specification uses Status values "Validation Requested" and This specification uses Status values "Validation Requested" and
"Validation Failed", which are defined in [RFC8505]. No other new "Validation Failed", which are defined in [RFC8505]. No other new
Status values are defined. Status values are defined.
4.3. Crypto-ID Parameters Option 4.3. Crypto-ID Parameters Option
This specification defines the Crypto-ID Parameters Option (CIPO), as This specification defines the Crypto-ID Parameters Option (CIPO).
a variation of the CGA Option that carries the parameters used to It carries the parameters used to form a Crypto-ID. In order to
form a Crypto-ID. In order to provide cryptographic agility provide cryptographic agility [RFC7696], this specification supports
[RFC7696], this specification supports different elliptic curves, different elliptic curves, indicated by a Crypto-Type field. NIST
indicated by a Crypto-Type field. NIST P-256 [FIPS186-4] MUST be P-256 [FIPS186-4] MUST be supported by all implementations. The
supported by all implementations. The Edwards-Curve Digital Edwards-Curve Digital Signature Algorithm (EdDSA) curve Ed25519
Signature Algorithm (EdDSA) curve Ed25519 (PureEdDSA) [RFC8032] MAY (PureEdDSA) [RFC8032] MAY be supported as an alternate.
be supported as an alternate.
The type of cryptographic algorithm used in the calculation of the
Crypto-ID is signaled by the Crypto-Type field of the CIPO as
specified in Table 1 in Section 8.2. Although the different
signature schemes target similar cryptographic strength, they rely on
different curves, hash functions, signature algorithms, and/or
representation conventions.
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 | Reserved | | Type | Length | Pad Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Crypto-Type | Modifier | Reserved | | Crypto-Type | Modifier | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| | | |
skipping to change at page 8, line 47 skipping to change at page 8, line 39
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
. . . .
. Padding . . Padding .
. . . .
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Crypto-ID Parameters Option Figure 2: Crypto-ID Parameters Option
Type: 11. This is the same value as the CGA Option, CIPO Type: to be assigned by IANA, see Table 1.
is a particular case of the CGA option
Length: 8-bit unsigned integer. The length of the option in Length: 8-bit unsigned integer. The length of the option in
units of 8 octets. units of 8 octets.
Modifier: 8-bit unsigned integer.
Pad Length: 8-bit unsigned integer. The length of the Padding Pad Length: 8-bit unsigned integer. The length of the Padding
field. field.
Reserved: This field is unused. It MUST be initialized to zero
by the sender and MUST be ignored by the receiver.
Crypto-Type: The type of cryptographic algorithm used in Crypto-Type: The type of cryptographic algorithm used in
calculation Crypto-ID (see Table 1 in Section 8.2). calculation Crypto-ID (see Table 2 in Section 8.3).
Although the different signature schemes target
similar cryptographic strength, they rely on
different curves, hash functions, signature
algorithms, and/or representation conventions.
Modifier: 8-bit unsigned integer. Set to an arbitrary value by
the creator of the Crypto-ID. The role of the
modifier is to enable the formation of multiple
Crypto-IDs from a same key pair, which reduces the
traceability and thus improves the privacy of a
constrained node that could not maintain many key-
pairs.
Public Key: JWK-Encoded Public Key [RFC7517]. Public Key: JWK-Encoded Public Key [RFC7517].
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.
The implementation of multiple hash functions in a constrained The implementation of multiple hash functions in a constrained
devices may consume excessive amounts of program memory. devices may consume excessive amounts of program memory.
[I-D.ietf-lwig-curve-representations] provides information on how to [I-D.ietf-lwig-curve-representations] provides information on how to
represent Montgomery curves and (twisted) Edwards curves as curves in represent Montgomery curves and (twisted) Edwards curves as curves in
short-Weierstrass form and illustrates how this can be used to short-Weierstrass form and illustrates how this can be used to
implement elliptic curve computations using existing implementations implement elliptic curve computations using existing implementations
that already provide, e.g., ECDSA and ECDH using NIST [FIPS186-4] that already provide, e.g., ECDSA and ECDH using NIST [FIPS186-4]
prime curves. prime curves.
For more details on representation conventions, we refer to For more details on representation conventions, we refer to
Appendix B. Appendix B.
skipping to change at page 9, line 31 skipping to change at page 9, line 35
[I-D.ietf-lwig-curve-representations] provides information on how to [I-D.ietf-lwig-curve-representations] provides information on how to
represent Montgomery curves and (twisted) Edwards curves as curves in represent Montgomery curves and (twisted) Edwards curves as curves in
short-Weierstrass form and illustrates how this can be used to short-Weierstrass form and illustrates how this can be used to
implement elliptic curve computations using existing implementations implement elliptic curve computations using existing implementations
that already provide, e.g., ECDSA and ECDH using NIST [FIPS186-4] that already provide, e.g., ECDSA and ECDH using NIST [FIPS186-4]
prime curves. prime curves.
For more details on representation conventions, we refer to For more details on representation conventions, we refer to
Appendix B. Appendix B.
4.4. Nonce Option 4.4. NDP Signature Option
This document reuses the Nonce Option defined in section 5.3.2. of The format of the NDP Signature Option (NDPSO) is illustrated in
SEND [RFC3971] without a change. Figure 3.
4.5. NDP Signature Option As opposed to the RSA Signature Option (RSAO) defined in section 5.2.
of SEND [RFC3971], the NDPSO does not have a key hash field. The
hash that can be used as index is the 128 leftmost bits of the ROVR
field in the EARO. The CIPO may be present in the same message as
the NDPSO. If not, it an be found in an abstract table that was
created by a previous message and indexed by the hash.
This document reuses the RSA Signature Option (RSAO) defined in 0 1 2 3
section 5.2. of SEND [RFC3971]. Admittedly, the name is ill-chosen 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
since the option is extended for non-RSA Signatures and this +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
specification defines an alias to avoid the confusion. | Type | Length | Pad Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| |
. .
. Digital Signature .
. .
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Padding .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The description of the operation on the option detailed in section Figure 3: NDP signature Option
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 Type: to be assigned by IANA, see Table 1.
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 Length: 8-bit unsigned integer. The length of the option in
signature indicated in the Crypto-Type field of the CIPO option units of 8 octets.
using the private-key corresponding the public-key passed in the
CIPO.
o The alias NDP Signature Option (NDPSO) can be used to refer to the Pad Length: 8-bit unsigned integer. The length of the Padding
RSAO when used as described in this specification. field.
Digital Signature: A variable-length field containing a digital
signature. The computation of the digital signature
depends on the Crypto-Type which is found in the
associated CIPO. For the values of the Crypto-Type
that are defined in ths specification, the signature
is computed as detailed in Section 6.2.
Padding: A variable-length field making the option length a
multiple of 8, containing as many octets as specified
in the Pad Length field. Typically there is no need
of a padding and the field is NULL.
5. Protocol Scope 5. Protocol Scope
The scope of the protocol specified here is a 6LoWPAN Low Power Lossy The scope of the protocol specified here is a 6LoWPAN Low Power Lossy
Network (LLN), typically a stub network connected to a larger IP Network (LLN), typically a stub network connected to a larger IP
network via a Border Router called a 6LBR per [RFC6775]. A 6LBR has network via a Border Router called a 6LBR per [RFC6775]. A 6LBR has
sufficient capability to satisfy the needs of duplicate address sufficient capability to satisfy the needs of duplicate address
detection. detection.
The 6LBR maintains registration state for all devices in its attached The 6LBR maintains registration state for all devices in its attached
skipping to change at page 10, line 38 skipping to change at page 11, line 33
| |
+-----+ +-----+
| | 6LBR | | 6LBR
+-----+ +-----+
o o o o o o
o o o o o o o o
o o LLN o o o o o LLN o o o
o o o (6LR) o o o (6LR)
o (6LN) o (6LN)
Figure 3: Basic Configuration Figure 4: Basic Configuration
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 mandates that the peer-wise layer-2 security is This specification mandates 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 mandates that a chain of trust is 6LRs. This specification mandates 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 other on-path 6LRs to the 6LBR. be safely routed by other on-path 6LRs to the 6LBR.
skipping to change at page 11, line 33 skipping to change at page 12, line 24
material avoids the constrained device to compute multiple keys for material avoids the constrained device to compute multiple keys for
multiple addresses. The registration process allows the node to use multiple addresses. The registration process allows the node to use
the same Crypto-ID for all of its addresses. the same Crypto-ID for all of its addresses.
6.1. First Exchange with a 6LR 6.1. First Exchange with a 6LR
A 6LN registers to a 6LR that is one hop away from it with the "C" A 6LN registers to a 6LR that is one hop away from it with the "C"
flag set in the EARO, indicating that the ROVR field contains a flag set in the EARO, indicating that the ROVR field contains a
Crypto-ID. The Target Address in the NS message indicates the IPv6 Crypto-ID. The Target Address in the NS message indicates the IPv6
address that the 6LN is trying to register. The on-link (local) address that the 6LN is trying to register. The on-link (local)
protocol interactions are shown in Figure 4. If the 6LR does not protocol interactions are shown in Figure 5. If the 6LR does not
have a state with the 6LN that is consistent with the NS(EARO), then have a state with the 6LN that is consistent with the NS(EARO), then
it replies with a challenge NA (EARO, status=Validation Requested) it replies with a challenge NA (EARO, status=Validation Requested)
that contains a Nonce Option (shown as NonceLR in Figure 4). The that contains a Nonce Option (shown as NonceLR in Figure 5). The
Nonce option MUST contain a random Nonce value that was never used Nonce option MUST contain a random Nonce value that was never used
with this device. with this device.
The 6LN replies to the challenge with an NS(EARO) that includes a new The 6LN replies to the challenge with an NS(EARO) that includes a new
Nonce option (shown as NonceLN in Figure 4), the CIPO (Section 4.3), Nonce option (shown as NonceLN in Figure 5), the CIPO (Section 4.3),
and the NDPSO containing the signature. The information associated and the NDPSO containing the signature. The information associated
to a Crypto-ID stored by the 6LR on the first NS exchange where it to a Crypto-ID stored by the 6LR on the first NS exchange where it
appears. The 6LR MUST store the CIPO parameters associated with the appears. The 6LR MUST store the CIPO parameters associated with the
Crypto-ID so it can be used for more than one address. Crypto-ID so it can be used for more than one address.
6LN 6LR 6LN 6LR
| | | |
|<------------------------- RA -------------------------| |<------------------------- RA -------------------------|
| | ^ | | ^
|---------------- NS with EARO (Crypto-ID) ------------>| | |---------------- NS with EARO (Crypto-ID) ------------>| |
skipping to change at page 12, line 30 skipping to change at page 13, line 30
| | | |
|<------------------- NA with EARO ---------------------| |<------------------- NA with EARO ---------------------|
| | | |
... ...
| | | |
|--------------- NS with EARO (Crypto-ID) ------------->| |--------------- NS with EARO (Crypto-ID) ------------->|
| | | |
|<------------------- NA with EARO ---------------------| |<------------------- NA with EARO ---------------------|
| | | |
Figure 4: On-link Protocol Operation Figure 5: On-link Protocol Operation
The steps for the registration to the 6LR are as follows: The steps for the registration to the 6LR are as follows:
o Upon the first exchange with a 6LR, a 6LN will be challenged to o Upon the first exchange with a 6LR, a 6LN will be challenged to
prove ownership of the Crypto-ID and the Target Address being prove ownership of the Crypto-ID and the Target Address being
registered in the Neighbor Solicitation message. When a 6LR registered in the Neighbor Solicitation message. When a 6LR
receives a NS(EARO) registration with a new Crypto-ID as a ROVR, receives a NS(EARO) registration with a new Crypto-ID as a ROVR,
it SHOULD challenge by responding with a NA(EARO) with a status of it SHOULD challenge by responding with a NA(EARO) with a status of
"Validation Requested". "Validation Requested".
o The challenge is triggered when the registration for a Source o The challenge is triggered when the registration for a Source
Link-Layer Address is not verifiable either at the 6LR or the Link-Layer Address is not verifiable either at the 6LR or the
6LBR. In the latter case, the 6LBR returns a status of 6LBR. In the latter case, the 6LBR returns a status of
"Validation Requested" in the DAR/DAC exchange, which is echoed by "Validation Requested" in the DAR/DAC exchange, which is echoed by
the 6LR in the NA (EARO) back to the registering node. The the 6LR in the NA (EARO) back to the registering node. The
challenge MUST NOT alter a valid registration in the 6LR or the challenge MUST NOT alter a valid registration in the 6LR or the
6LBR. 6LBR.
o Upon receiving a NA(EARO) with a status of "Validation Requested", o Upon receiving a first NA(EARO) with a status of "Validation
the registering node SHOULD retry its registration with a Crypto- Requested" from a 6LR, the registering node SHOULD retry its
ID Parameters Option (CIPO) (Section 4.3) that contains all the registration with a Crypto-ID Parameters Option (CIPO)
necessary material for building the Crypto-ID, the NonceLN that it (Section 4.3) that contains all the necessary material for
generated, and the NDP signature (Section 4.5) option that proves building the Crypto-ID, the NonceLN that it generated, and the NDP
its ownership of the Crypto-ID and intent of registering the signature (Section 4.4) option that proves its ownership of the
Target Address. Crypto-ID and intent of registering the Target Address. In
subsequent revalidation with the same 6LR, the 6LN MAY try to omit
the CIPO to save bandwidth, with the expectation that the 6LR
saved it. If the validation fails and it gets challenged again,
then it SHOULD add the CIPO again.
o In order to validate the ownership, the 6LR performs the same o In order to validate the ownership, the 6LR performs the same
steps as the 6LN and rebuilds the Crypto-ID based on the steps as the 6LN and rebuilds the Crypto-ID based on the
parameters in the CIPO. It also verifies the signature contained parameters in the CIPO. If the rebuilt Crypto-ID matches the
in the NDPSO option. If the Crypto-ID does not match with the ROVR, the 6LN also verifies the signature contained in the NDPSO
public-key in the CIPO option, or if the signature in the NDPSO option. If at that point the signature in the NDPSO option can be
option cannot be verified, the validation fails. verified, then the validation succeeds. Otherwise the validation
fails.
o If the 6LR fails to validate the signed NS(EARO), it responds with 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". After receiving a NA(EARO) with
a status of "Validation Failed", the registering node SHOULD try a status of "Validation Failed", the registering node SHOULD try
to register an alternate target address in the NS message. to register an alternate target address in the NS message.
6.2. NDPSO generation and verification 6.2. NDPSO generation and verification
The signature generated by the 6LN to provide proof-of-ownership of The signature generated by the 6LN to provide proof-of-ownership of
the private-key is carried in the NDP Signature Option (NDPSO). It the private-key is carried in the NDP Signature Option (NDPSO). It
is generated by the 6LN in a fashion that depends on the Crypto-Type is generated by the 6LN in a fashion that depends on the Crypto-Type
(see Table 1 in Section 8.2) chosen by the 6LN as follows: (see Table 2 in Section 8.3) chosen by the 6LN as follows:
o Concatenate the following in the order listed: o Concatenate the following in the order listed:
1. 128-bit type tag (in network byte order) 1. The 128-bit Message Type tag [RFC3972] (in network byte
order). For this specification the tag is 0x8701 55c8 0cca
dd32 6ab7 e415 f148 84d0. (The tag value has been generated
by the editor of this specification on random.org).
2. JWK-encoded public key 2. JWK-encoded public key
3. the 16-byte Target Address (in network byte order) sent in the 3. the 16-byte Target Address (in network byte order) sent in the
Neighbor Solicitation (NS) message. It is the address which Neighbor Solicitation (NS) message. It is the address which
the 6LN is registering with the 6LR and 6LBR. the 6LN is registering with the 6LR and 6LBR.
4. NonceLR received from the 6LR (in network byte order) in the 4. NonceLR received from the 6LR (in network byte order) in the
Neighbor Advertisement (NA) message. The random nonce is at Neighbor Advertisement (NA) message. The random nonce is at
least 6 bytes long as defined in [RFC3971]. least 6 bytes long as defined in [RFC3971].
skipping to change at page 14, line 9 skipping to change at page 15, line 18
7. 1-byte (in network byte order) Crypto-Type value sent in the 7. 1-byte (in network byte order) Crypto-Type value sent in the
CIPO option. CIPO option.
o Depending on the Crypto-Type, apply the hash function on this o Depending on the Crypto-Type, apply the hash function on this
concatenation. concatenation.
o Depending on the Crypto-Type, sign the hash output with ECDSA (if o Depending on the Crypto-Type, sign the hash output with ECDSA (if
curve P-256 is used) or sign the hash with EdDSA (if curve Ed25519 curve P-256 is used) or sign the hash with EdDSA (if curve Ed25519
(PureEdDSA)). (PureEdDSA)).
The 6LR on receiving the NDPSO and CIPO options first hashes the JWK The 6LR on receiving the NDPSO and CIPO options first Regenerates the
encoded public-key in the CIPO option to make sure that the leftmost Crypto-ID based on the CIPO option to make sure that the leftmost
bits up to the size of the ROVR match. Only if the check is bits up to the size of the ROVR match. Only if the check is
successful, it tries to verify the signature in the NDPSO option successful, it tries to verify the signature in the NDPSO option
using the following. using the following.
o Concatenate the following in the order listed: o Concatenate the following in the order listed:
1. 128-bit type tag (in network byte order) 1. 128-bit type tag (in network byte order)
2. JWK-encoded public key received in the CIPO option 2. JWK-encoded public key received in the CIPO option
skipping to change at page 15, line 12 skipping to change at page 16, line 21
maintain a security association, then there is no need to propagate maintain a security association, then there is no need to propagate
the proof of ownership to the 6LBR. the proof of ownership to the 6LBR.
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 a neighboring 6LR with an NS performs an initial registration to a neighboring 6LR with an NS
message that carries an Address Registration Option (EARO) [RFC8505]. message that carries an Address Registration Option (EARO) [RFC8505].
The 6LR validates the address with an 6LBR using a DAR/DAC exchange, The 6LR validates the address with an 6LBR using a DAR/DAC exchange,
and the 6LR confirms (or denies) the address ownership with an NA and the 6LR confirms (or denies) the address ownership with an NA
message that also carries an Address Registration Option. message that also carries an Address Registration Option.
Figure 5 illustrates a registration flow all the way to a 6LowPAN Figure 6 illustrates a registration flow all the way to a 6LowPAN
Backbone Router (6BBR) [I-D.ietf-6lo-backbone-router]. Backbone Router (6BBR) [I-D.ietf-6lo-backbone-router].
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 15, line 37 skipping to change at page 16, line 46
| | | | <wait> | | | | <wait>
| | | | | | | |
| | | proxy NA(EARO) | | | | proxy NA(EARO) |
| | |<---------------| | | |<---------------|
| | Extended DAC | | | | Extended DAC | |
| |<--------------| | | |<--------------| |
| NA(EARO) | | | | NA(EARO) | | |
|<---------------| | | |<---------------| | |
| | | | | | | |
Figure 5: (Re-)Registration Flow Figure 6: (Re-)Registration Flow
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 AP-ND we extend DAR/DAC messages to carry cryptographically In AP-ND we extend DAR/DAC messages to carry cryptographically
generated ROVR. In a multihop 6LoWPAN, the node exchanges the generated ROVR. In a multihop 6LoWPAN, the node exchanges the
messages shown in Figure 5. The 6LBR must identify who owns an messages shown in Figure 6. 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. 6LR.
7. Security Considerations 7. Security Considerations
7.1. Inheriting from RFC 3971 7.1. Inheriting from RFC 3971
Observations regarding the following threats to the local network in Observations regarding the following threats to the local network in
[RFC3971] also apply to this specification. [RFC3971] also apply to this specification.
skipping to change at page 18, line 19 skipping to change at page 19, line 43
The same private key MUST NOT be reused with more than one signature The same private key MUST NOT be reused with more than one signature
scheme in this specification. scheme in this specification.
8. IANA considerations 8. IANA considerations
8.1. CGA Message Type 8.1. CGA Message Type
This document defines a new 128-bit value under the CGA Message Type This document defines a new 128-bit value under the CGA Message Type
[RFC3972] name space: 0x8701 55c8 0cca dd32 6ab7 e415 f148 84d0. [RFC3972] name space: 0x8701 55c8 0cca dd32 6ab7 e415 f148 84d0.
8.2. Crypto-Type Subregistry 8.2. IPv6 ND option types
This document registers two new ND option types under the subregistry
"IPv6 Neighbor Discovery Option Formats":
+------------------------------+----------------+-------------------+
| Option Name | Suggested | Defined in |
| | value | |
+------------------------------+----------------+-------------------+
| Crypto-ID Parameters Option | 39 | This_RFC Section |
| (CIPO) | | 4.3 |
| NDP Signature Option (NDPSO) | 38 | This_RFC Section |
| | | 4.4 |
+------------------------------+----------------+-------------------+
Table 1: New ND options
8.3. Crypto-Type Subregistry
IANA is requested to create a new subregistry "Crypto-Type IANA is requested to create a new subregistry "Crypto-Type
Subregistry" in the "Internet Control Message Protocol version 6 Subregistry" in the "Internet Control Message Protocol version 6
(ICMPv6) Parameters". The registry is indexed by an integer in the (ICMPv6) Parameters". The registry is indexed by an integer in the
interval 0..255 and contains an Elliptic Curve, a Hash Function, a interval 0..255 and contains an Elliptic Curve, a Hash Function, a
Signature Algorithm, and Representation Conventions, as shown in Signature Algorithm, and Representation Conventions, as shown in
Table 1, which together specify a signature scheme. The following Table 2, which together specify a signature scheme. The following
Crypto-Type values are defined in this document: Crypto-Type values are defined in this document:
+----------------+-----------------+-------------+------------------+ +----------------+-----------------+-------------+------------------+
| Crypto-Type | 0 (ECDSA256) | 1 (Ed25519) | 2 (ECDSA25519) | | Crypto-Type | 0 (ECDSA256) | 1 (Ed25519) | 2 (ECDSA25519) |
| value | | | | | value | | | |
+----------------+-----------------+-------------+------------------+ +----------------+-----------------+-------------+------------------+
| Elliptic curve | NIST P-256 | Curve25519 | Curve25519 | | Elliptic curve | NIST P-256 | Curve25519 | Curve25519 |
| | [FIPS186-4] | [RFC7748] | [RFC7748] | | | [FIPS186-4] | [RFC7748] | [RFC7748] |
| | | | | | | | | |
| Hash function | SHA-256 | SHA-512 | SHA-256 | | Hash function | SHA-256 | SHA-512 | SHA-256 |
skipping to change at page 18, line 51 skipping to change at page 20, line 49
| | | | | | | | | |
| Representation | Weierstrass, | Edwards, | Weierstrass, | | Representation | Weierstrass, | Edwards, | Weierstrass, |
| conventions | (un)compressed, | compressed, | (un)compressed, | | conventions | (un)compressed, | compressed, | (un)compressed, |
| | MSB/msb first | LSB/lsb | MSB/msb first | | | MSB/msb first | LSB/lsb | MSB/msb first |
| | | first | | | | | first | |
| | | | | | | | | |
| Defining | RFC THIS | RFC THIS | RFC THIS | | Defining | RFC THIS | RFC THIS | RFC THIS |
| specification | | | | | specification | | | |
+----------------+-----------------+-------------+------------------+ +----------------+-----------------+-------------+------------------+
Table 1: Crypto-Types Table 2: Crypto-Types
New Crypto-Type values providing similar or better security (with New Crypto-Type values providing similar or better security (with
less code) may be defined in the future. less code) may be defined in the future.
Assignment of new values for new Crypto-Type MUST be done through 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].
9. Acknowledgments 9. Acknowledgments
skipping to change at page 20, line 44 skipping to change at page 22, line 44
<https://link.springer.com/ <https://link.springer.com/
chapter/10.1007/978-3-319-76953-0_1>. chapter/10.1007/978-3-319-76953-0_1>.
[I-D.ietf-6lo-backbone-router] [I-D.ietf-6lo-backbone-router]
Thubert, P., Perkins, C., and E. Levy-Abegnoli, "IPv6 Thubert, P., Perkins, C., and E. Levy-Abegnoli, "IPv6
Backbone Router", draft-ietf-6lo-backbone-router-11 (work Backbone Router", draft-ietf-6lo-backbone-router-11 (work
in progress), February 2019. in progress), February 2019.
[I-D.ietf-lwig-curve-representations] [I-D.ietf-lwig-curve-representations]
Struik, R., "Alternative Elliptic Curve Representations", Struik, R., "Alternative Elliptic Curve Representations",
draft-ietf-lwig-curve-representations-01 (work in draft-ietf-lwig-curve-representations-03 (work in
progress), November 2018. progress), March 2019.
[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,
 End of changes. 44 change blocks. 
128 lines changed or deleted 191 lines changed or added

This html diff was produced by rfcdiff 1.47. The latest version is available from http://tools.ietf.org/tools/rfcdiff/