Network Working Group D. Garcia
Internet-Draft R. Marin
Intended status: Experimental University of Murcia
Expires: December 1, 2016 A. Kandasamy
A. Pelov
Acklio
May 30, 2016
LoRaWAN Authentication in RADIUS
draft-garcia-radext-radius-lorawan-00
Abstract
This document describes a proposal for adding LoRaWAN support in
RADIUS. The purpose is to integrate the LoRaWAN network join
procedure with an Authentication, Authorization and Accounting (AAA)
infrastructure based on RADIUS.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. LoRaWAN support in RADIUS . . . . . . . . . . . . . . . . . . 4
3. LoRaWAN joining procedure . . . . . . . . . . . . . . . . . . 4
4. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 5
4.1. Protocol Assumptions . . . . . . . . . . . . . . . . . . 5
4.2. Protocol Exchange . . . . . . . . . . . . . . . . . . . . 5
4.2.1. Join-Request Attribute . . . . . . . . . . . . . . . 6
4.2.2. Join-Answer Attribute . . . . . . . . . . . . . . . . 6
4.2.3. AppSKey Attribute . . . . . . . . . . . . . . . . . . 6
4.2.4. NwkSKey Attribute . . . . . . . . . . . . . . . . . . 6
5. RADIUS-Diameter Interaction . . . . . . . . . . . . . . . . . 7
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7
7. Security Considerations . . . . . . . . . . . . . . . . . . . 7
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
9.1. Normative References . . . . . . . . . . . . . . . . . . 7
9.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
Low Power Wide Area Network (LP-WAN) groups several radio
technologies that allow communications with nodes far from the
central communication endpoint (base station) in the range of
kilometers depending on the specifics of the technology and the
scenario. They are fairly recent and the protocols to manage those
infrastructures are in continuous development. In some cases they
may not consider aspects such as key management or directly tackle
scalability issue in terms of authentication and authorization. The
nodes to be authenticated and authorized is expected to be
considerably high in number. One of the protocols that provide a
complete solution is LoRaWAN [LoRaWAN]. LoRaWAN is a MAC layer
protocol that use LoRa as its physical medium to cover long range
(up-to 20km depending on the environment) devices. LoRaWAN is
designed for large scale networks and currently has a central entity
called network server which maintains a pre-configured key named
AppKey for each of the devices on the network. Furthermore, session
keys such as NwkSKey and AppSKey used for encryption of data
messages, are derived with the help of this AppKey. Since each
service provider would operate their network server individually,
authenticating the devices becomes a tedious process because of
inter-interoperability or the roaming challenges between the
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operators. As we know the AAA infrastructure provides a flexible,
scalable solution. They offer an opportunity to manage all these
proceses in a centralized manner as happens in other type of networks
(e.g. cellular, wifi, etc...) making it an interesting asset when
integrated into the LoRaWAN architecture.
+-------+ +-------+ +--------+
+------+ | | | | | |
| +--(LoRa)--+ +--(IP)--+ +-----(IP)-----+ |
+------+ | | | | | |
+-------+ +-------+ +--------+
End-Device Gateway Network Application
Server Server
Figure 1: LoRAWAN Architecture
The End-Device communicates with the Gateway by using the LoRa
modulation. The Gateway acts as a simple transceiver, which forwards
all data do the Network Server, which performs the processing of the
frames, network frame authentication (MIC verification), and which
serves as Network Access Port. The Application Server can be
handling user data OR can be used during the join procedure to accept
an End-Node to the network. In this case, the Application Server is
called a Join Server. This document describes a way to use standard
RADIUS servers as a Join Server, and to use the RADIUS protocol for
the interaction between the Network Server and the Application
Server.
+-------+ +-------+ +--------+
+------+ | | | | | |
|AppKey+--(LoRa)--+ +--(IP)--+ +---(RADIUS)---+ AppKey |
+------+ | | | | | |
+-------+ +-------+ +--------+
End-Device Gateway Network RADIUS
Server Server
(+ RADIUS client)
Figure 2: LoRAWAN Architecture with AAA and RADIUS authentication.
End-Device and RADIUS server have a shared secret - the AppKey, which
is used to derive the session keys (NwkSKey and AppSKey).
The document describes how LoRaWAN join procedure is integrated with
AAA infrastructure using RADIUS [RFC2865] by defining the new
attributes needed to support the LoRaWAN exchange.
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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. LoRaWAN support in RADIUS
Regarding the overall functionality, the RADIUS LoRaWAN support
defines the new Attributes needed for the management of the join
procedure. A NAS (RADIUS client) that that intends to support this
specification MUST implement the RADIUS attributes for this service.
The NAS-Port-Type specifying the type of port on which the NAS is
authenticating the end-device in this case MAY be 18 ( Wireless -
Other ) or a new one specifically assigned for LoRaWAN (TBD.).
3. LoRaWAN joining procedure
The LoRaWAN joining procedure as described in the LoRaWAN
Specification 1.0 [LoRaWAN] consists on one exchange. The first
message of this exchange is called join-request (JR) message and is
sent from the end-device to the network server containing the AppEUI
and DevEUI of the end-device with additionally a nonce of 2 octets
called DevNonce. See Figure 3
+-------------+-------------+-------------+
Size (bytes) | 8 | 8 | 2 |
+---------------------------+-------------+-------------+
Join Request | AppEUI | DevEUI | DevNonce |
+-------------+-------------+-------------+
Figure 3: Join Request Message
In response to the join-request, the other endpoint will answer with
the join-accept (JA) (Figure 4) if the end-device is successfully
authenticated and authorized to join the network. The join-accept
contains a nonce (AppNonce), a network identifier (NetID), an end-
device address (DevAddr), a delay between the TX and RX (RxDelay)
and, optionally, the CFList (see LoRaWAN specification [LoRaWAN]
section 7).
+--------+-----+-------+----------+-------+-------------+
Size (bytes)| 3 | 3 | 4 | 1 | 1 |16 (Optional)|
+-------------------------------------------------------------------+
Join Accept |AppNonce|NetID|DevAddr|DLSettings|RxDelay| CFList |
+--------+-----+-------+----------+-------+-------------+
Figure 4: Join Accept Message
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4. Protocol Overview
4.1. Protocol Assumptions
For the proposal for LoRaWAN support in RADIUS next we describe some
assumptions regarding the LoRaWAN specification. The first is that
the AppKey is only shared between the AAA server and the end-device.
The outcome of the successful join procedure (i.e. NwkSKey and
AppSKey) are sent from the AAA server to the network-server. This
allows for the end-device to exchange message with the network-
server, once the join procedure is finished, as specified in LoRaWAN
[LoRaWAN].
4.2. Protocol Exchange
The join procedure between the end-device and the network-server
entails one exchange consisting on a join-request message and a join-
response message. In RADIUS the network-server implements a RADIUS
client to communicate with the AAA Server. Upon reception of the
LoRaWAN join-request message, the network-server creates an Access-
Request message, with the Join-Request attribute containing the
original message from the end-device, and the Join-Answer Attribute
with all the fields, except for the MIC that will be calculated by
the AAA Server, since is the one that holds the AppKey. Once the AAA
Server authenticates and authorizes the end-device, sends back the
Join-Answer with the MIC generated as specified by the LoRaWAN
specification. Furthermore, as a consequence of a successful join
procedure, the AppSKey (optional) and NwkSKey are generated and sent
along in AppSKey and NwkSKey Attributes respectively. The NAS
receives the Access-Accept (if successful), obtains the content of
the Join-Request attribute and sends it to the end-device, storing in
association with that end-device the NwSKey and the AppSKey.
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network-server AAA
end-device (NAS) Server
----------- --------- -------
| | |
| JR[MIC] | Access-Request |
|------------------------>| Join-Request Att |
| | Join-Answer Att* |
| |----------------------------------->|
| | |
| gen | | gen
| | | | |
| | | Access-Accept | |
| v | Join-Answer Att | v
| AppSKey | AppSKey Att* | AppSKey
| NwkSKey | NwSKey Att | NwkSKey
| |<-----------------------------------|
| JA[MIC] | |
|<------------------------| |
| | |
Figure 5: Protocol
4.2.1. Join-Request Attribute
This Attribute contains the original Join-Request message. This
attribute will only appear in the Access-Request message.
4.2.2. Join-Answer Attribute
This Attribute is used in both Access-Request and Access-Accept
messages. In the first case it contains the Join Answer message with
all the needed values filled by the network-server so the AAA server
that holds the AppKey is able to create the MIC, that in this case is
not present (marked with an *). In the second case, it contains the
message with the MIC generated by the AAA server.
4.2.3. AppSKey Attribute
This Attribute contains the AppSKey, an application session key
specific for the end-device. This attribute is optional, and will
only appear in the Access-Accept message.
4.2.4. NwkSKey Attribute
This Attribute contains the NwkSKey, an network session key specific
for the end-device. This attribute will only appear in the Access-
Accept message.
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5. RADIUS-Diameter Interaction
TBD.
6. Acknowledgments
This work has been possible partially by the SMARTIE project
(FP7-SMARTIE-609062 EU Project) and the Spanish National Project
CICYT EDISON (TIN2014-52099-R) granted by the Ministry of Economy and
Competitiveness of Spain (including ERDF support).
7. Security Considerations
TBD.
8. IANA Considerations
This document has no actions for IANA.
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)",
RFC 2865, DOI 10.17487/RFC2865, June 2000,
<http://www.rfc-editor.org/info/rfc2865>.
9.2. Informative References
[LoRaWAN] Sornin, N., Luis, M., Eirich, T., and T. Kramp, "LoRa
Specification V1.0", January 2015, <https://www.lora-
alliance.org/>.
Authors' Addresses
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Dan Garcia-Carrillo (Ed.)
University of Murcia
Campus de Espinardo S/N, Faculty of Computer Science
Murcia 30100
Spain
Phone: +34 868 88 78 82
Email: dan.garcia@um.es
Rafa 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
Arunprabhu Kandasamy
Acklio
2bis rue de la Chataigneraie
35510 Cesson-Sevigne Cedex
France
Email: arun@ackl.io
Alexander Pelov
Acklio
2bis rue de la Chataigneraie
35510 Cesson-Sevigne Cedex
France
Email: a@ackl.io
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