EAP method based on EDHOC Authentication
draft-ingles-eap-edhoc-00
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| Authors | Eduardo Ingles Sanchez , Dan Garcia-Carillo , Rafael Marin-Lopez | ||
| Last updated | 2020-08-06 | ||
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draft-ingles-eap-edhoc-00
Network Working Group E. Ingles
Internet-Draft University of Murcia
Intended status: Experimental D. Garcia-Carrillo
Expires: February 7, 2021 Odin Solutions S.L.
R. Marin-Lopez
University of Murcia
August 6, 2020
EAP method based on EDHOC Authentication
draft-ingles-eap-edhoc-00
Abstract
This document describes a proposal of an EAP method based on the
EDHOC authentication protocol .
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 2
2.1. The EAP-EDHOC Conversation . . . . . . . . . . . . . . . 2
2.1.1. Identity . . . . . . . . . . . . . . . . . . . . . . 4
3. Identity Verification . . . . . . . . . . . . . . . . . . . . 4
4. Key Hierarchy . . . . . . . . . . . . . . . . . . . . . . . . 5
5. IANA considerations . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
8. Normative References . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
EDHOC [I-D.selander-lake-edhoc] is a new protocol for autentication
and key derivation that has been proposed as an alternative in IoT to
provide a secure exchange in an end-to-end fashion. This key
material can be futher used to run other protocols such as OSCORE, as
well as providing key material to any other protocol that needs pre-
shared key material to secure the communications. Provides
authentication and key material generation, which are basic pillars
to the design of an EAP method. And indeed the most important thing
is that it is lightweight and designed for IoT. In addition, the
EDHOC implementation that exists on the device can be reused to
establish OSCORE Security Associations (SAs) for the authentication
process. EAP is a protocol that allows to implement different
authentication mechanims, provides a framework for key management and
has integration with AAA infrastructures. For these reasons, this
new EAP method will allow the different applications and use cases to
take advantage of EAP.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. Protocol Overview
2.1. The EAP-EDHOC Conversation
The EAP-EDHOC conversation typically starts with the negotiation of
EAP by the EAP authenticator and the EAP peer. The EAP authenticator
typically sends an EAP-Request/Identity packet to the EAP peer, to
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which the EAP peer answers with an EAP-Response/Identity. This last
messages contains the peer's user-Id.
From this point on, the authenticator MAY act as a forwarder of the
EAP messages between the EAP peer and the server, if the pass-through
mode is used, receiving the EAP packets from the peer, encapsulating
them for transmission to the EAP server that will act as
Authentication Server (AS).
Once the EAP server receives the peer's Identity, it MUST respond
with an an EAP-Request packet with EAP-Type=EAP-EDHOC and the
prefered EDHOC authentication credential mode in decresing order, or
no data if only one method is allowed or used. The EAP-EDHOC
conversation will then begin, with the peer sending an EAP-Response
packet with EAP-Type=EAP-EDHOC. The data field of that packet will
encapsulate the "EDHOC Message 1".
The EAP server will then respond with an EAP-Request packet with EAP-
Type=EAP-EDHOC. The data field of this packet will encapsulate
"EDHOC Message 2" message. To this message, the EAP peer will send
the and EAP-Response message containing the "EDHOC Message 3"
message.
In the case where the EDHOC mutual authentication is successful, the
conversation will appear as follows:
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+--------+ +-------+
| EAP | | EAP |
| Peer | | AuthN |
+--------+ +-------+
| EAP-Request/Identity |
| <---------------------------------------------------+ |
| |
| EAP-Response/Identity (ID) |
| +---------------------------------------------------> |
| EAP-Request/ |
| EAP-Type=EAP-EDHOC |
| (RPK,PSK) |
| <---------------------------------------------------+ |
| EAP-Response/ |
| EAP-Type=EAP-EDHOC |
| (EDHOC message 1) |
| +---------------------------------------------------> |
| EAP-Request/ |
| EAP-Type=EAP-EDHOC |
| (EDHOC message 2) |
| <---------------------------------------------------+ |
| EAP-Response/ |
| EAP-Type=EAP-EDHOC |
| (EDHOC message 3) |
| +---------------------------------------------------> |
| |
| EAP-Success |
| <---------------------------------------------------+ |
+ +
Figure 1: Overview EDHOC exchange
2.1.1. Identity
It is RECOMMENDED to use NAIs in the Identity Response as identities.
While
3. Identity Verification
The identity provided in the EAP-Response/Identity is not
authenticated by EAP-EDHOC, hence SHALL NOT be used for authorization
or accounting purposes. The authenticator and the EAP server MAY
examine the identity presented in EAP-Response/Identity for routing
and EAP method selection.
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4. Key Hierarchy
EDHOC uses HKDF RFC 5869 [RFC5869] to derive keys. HKDF-Extract is
used for deriving fixed-length uniformly pseudorandom keys (PRK) from
ECDH shared secrets. HKDF-Expand is used for deriving additional
output keying material (OKM) from the PRKs.
The derivation proceeds as follows:
PRK = HKDF-Extract( salt, IKM )
Where:
HKDF-Extract = RFC5869 HKDF function
salt = PSK when using symmetric keys, and the empty byte string when
using asymmetric keys
IKM (input keying material) = the ECDH shared secret
Figure 2 illustrates the EDHOC Key Hierarchy.
In EAP-EDHOC, the MSK, EMSK, and Initialization Vector (IV) are
derived from the PRK via a hash function. This ensures that the
EDHOC PRK cannot be derived from the MSK, EMSK, or IV unless the hash
function is defeated. Since the MSK and EMSK are derived from the
EDHOC PRK, if the EDHOC PRK is compromised then the MSK and EMSK are
also compromised.
EAP-EDHOC derives exported keying material and parameters as follows:
Type-Code = 0XFF
Key_Material = HKDF-Expand(EDHOC PRK, "EAP-EDHOC encryption", 128)
MSK = Key_Material(0,63)
EMSK = Key_Material(64,127)
IV = HKDF-Expand(EDHOC PRK, "EAP-EDHOC IV", 64)
Session-Id = Type-Code || Method-Id
Method-Id = HKDF-Expand(EDHOC PRK, "EAP_EDHOC_Method-Id", 64)
Where:
Key_Material(S,F) = Octets S through F inclusive of the key material.
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| PRK
V
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MSK, EMSK |
| label == "EAP-EDHOC encryption" |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |
| MSK(0,63) | EMSK(0,63) | IV (0,63)
| | |
| | |
V V V
Figure 2: EAP-EDHOC Key derivation
5. IANA considerations
TBD.
6. Security Considerations
TBD.
7. Acknowledgements
This work is possible due the EU Project IoTCrawlwer under grant
agreement n.779852, the EU Project INSPIRE-5Gplus under grant
agreement n.871808 and to the pre-doctoral grant Industrial PhD DI-
16-08432 granted to ODIN Solutions S.L
8. Normative References
[I-D.selander-lake-edhoc]
Selander, G., Mattsson, J., and F. Palombini, "Ephemeral
Diffie-Hellman Over COSE (EDHOC)", draft-selander-lake-
edhoc-01 (work in progress), March 2020.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2548] Zorn, G., "Microsoft Vendor-specific RADIUS Attributes",
RFC 2548, DOI 10.17487/RFC2548, March 1999,
<https://www.rfc-editor.org/info/rfc2548>.
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[RFC5869] Krawczyk, H. and P. Eronen, "HMAC-based Extract-and-Expand
Key Derivation Function (HKDF)", RFC 5869,
DOI 10.17487/RFC5869, May 2010,
<https://www.rfc-editor.org/info/rfc5869>.
Authors' Addresses
Eduardo Ingles-Sanchez
University of Murcia
Campus de Espinardo S/N, Faculty of Computer Science
Murcia 30100
Spain
Email: eduardo.ingles@um.es
Dan Garcia-Carrillo
Odin Solutions S.L.
Poligono Industrial Oeste, C/ Peru, 5
Alcantarilla, Murcia 30820
Spain
Email: dgarcia@odins.es
Rafael Marin-Lopez
University of Murcia
Campus de Espinardo S/N, Faculty of Computer Science
Murcia 30100
Spain
Phone: +34 868 88 85 01
Email: rafa@um.es
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