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Checking references for intended status: Experimental ---------------------------------------------------------------------------- == Missing Reference: 'MIC' is mentioned on line 364, but not defined Summary: 1 error (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group D. Garcia 3 Internet-Draft R. Marin 4 Intended status: Experimental University of Murcia 5 Expires: May 4, 2017 A. Kandasamy 6 A. Pelov 7 Acklio 8 October 31, 2016 10 LoRaWAN Authentication in RADIUS 11 draft-garcia-radext-radius-lorawan-02 13 Abstract 15 This document describes a proposal for adding LoRaWAN support in 16 RADIUS. The purpose is to integrate the LoRaWAN network join 17 procedure with an Authentication, Authorization and Accounting (AAA) 18 infrastructure based on RADIUS. 20 Status of This Memo 22 This Internet-Draft is submitted in full conformance with the 23 provisions of BCP 78 and BCP 79. 25 Internet-Drafts are working documents of the Internet Engineering 26 Task Force (IETF). Note that other groups may also distribute 27 working documents as Internet-Drafts. The list of current Internet- 28 Drafts is at http://datatracker.ietf.org/drafts/current/. 30 Internet-Drafts are draft documents valid for a maximum of six months 31 and may be updated, replaced, or obsoleted by other documents at any 32 time. It is inappropriate to use Internet-Drafts as reference 33 material or to cite them other than as "work in progress." 35 This Internet-Draft will expire on May 4, 2017. 37 Copyright Notice 39 Copyright (c) 2016 IETF Trust and the persons identified as the 40 document authors. All rights reserved. 42 This document is subject to BCP 78 and the IETF Trust's Legal 43 Provisions Relating to IETF Documents 44 (http://trustee.ietf.org/license-info) in effect on the date of 45 publication of this document. Please review these documents 46 carefully, as they describe your rights and restrictions with respect 47 to this document. Code Components extracted from this document must 48 include Simplified BSD License text as described in Section 4.e of 49 the Trust Legal Provisions and are provided without warranty as 50 described in the Simplified BSD License. 52 Table of Contents 54 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 55 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4 56 2. LoRaWAN support in RADIUS . . . . . . . . . . . . . . . . . . 4 57 3. LoRaWAN Overview . . . . . . . . . . . . . . . . . . . . . . 4 58 3.1. Introduction . . . . . . . . . . . . . . . . . . . . . . 4 59 3.2. LoRaWAN join procedure Key Material . . . . . . . . . . . 4 60 3.3. LoRaWAN joining procedure . . . . . . . . . . . . . . . . 5 61 3.4. LoRaWAN Key Derivation . . . . . . . . . . . . . . . . . 6 62 4. Integration Overview . . . . . . . . . . . . . . . . . . . . 7 63 4.1. Mapping LoRaWAN Entities to AAA Infrastructure . . . . . 7 64 4.2. Assumptions . . . . . . . . . . . . . . . . . . . . . . . 7 65 4.3. Protocol Exchange . . . . . . . . . . . . . . . . . . . . 7 66 4.3.1. Join-Request Attribute . . . . . . . . . . . . . . . 8 67 4.3.2. Join-Answer Attribute . . . . . . . . . . . . . . . . 9 68 4.3.3. AppSKey Attribute . . . . . . . . . . . . . . . . . . 10 69 4.3.4. NwkSKey Attribute . . . . . . . . . . . . . . . . . . 11 70 4.3.5. Table of Attribute . . . . . . . . . . . . . . . . . 11 71 5. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 12 72 6. Security Considerations . . . . . . . . . . . . . . . . . . . 12 73 7. Proof of concept implementation . . . . . . . . . . . . . . . 13 74 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14 75 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 76 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 77 10.1. Normative References . . . . . . . . . . . . . . . . . . 15 78 10.2. Informative References . . . . . . . . . . . . . . . . . 15 79 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 81 1. Introduction 83 Low Power Wide Area Network (LP-WAN) groups several radio 84 technologies that allow communications with nodes far from the 85 central communication endpoint (base station) in the range of 86 kilometers depending on the specifics of the technology and the 87 scenario. They are fairly recent and the protocols to manage those 88 infrastructures are in continuous development. In some cases they 89 may not consider aspects such as key management or directly tackle 90 scalability issue in terms of authentication and authorization. The 91 nodes to be authenticated and authorized is expected to be 92 considerably high in number. One of the protocols that provide a 93 complete solution is LoRaWAN [LoRaWAN]. LoRaWAN is a MAC layer 94 protocol that use LoRa as its physical medium to cover long range 95 (up-to 20 km depending on the environment) devices. LoRaWAN is 96 designed for large scale networks and currently has a central entity 97 called Network Server which maintains a pre-configured key named 98 AppKey for each of the devices on the network. Furthermore, session 99 keys such as NwkSKey and AppSKey used for encryption of data 100 messages, are derived with the help of this AppKey. Since each 101 service provider would operate their Network Server individually, 102 authenticating the devices becomes a tedious process because of 103 inter-interoperability or the roaming challenges between the 104 operators. An illustration of the LoRaWAN architecture can be seen 105 in figure Figure 1. As we know the AAA infrastructure provides a 106 flexible, scalable solution. They offer an opportunity to manage all 107 these processes in a centralized manner as happens in other type of 108 networks (e.g. cellular, WiFi, etc...) making it an interesting asset 109 when integrated into the LoRaWAN architecture. 111 +-------+ +-------+ +--------+ 112 +------+ | | | | | | 113 | +--(LoRa)--+ +--(IP)--+ +-----(IP)-----+ | 114 +------+ | | | | | | 115 +-------+ +-------+ +--------+ 116 End-Device Gateway Network Join 117 Server Server 119 Figure 1: LoRAWAN Architecture 121 The End-Device communicates with the Gateway by using the LoRa 122 modulation. The Gateway acts as a simple transceiver, which forwards 123 all data do the Network Server, which performs the processing of the 124 frames, network frame authentication (MIC verification), and which 125 serves as Network Access Port. This document describes a way to use 126 standard RADIUS servers as a Join Server, and to use the RADIUS 127 protocol for the interaction between the Network Server and the 128 Application Server. This integration is illustrated in figure 129 Figure 2 131 +-------+ +-------+ +--------+ 132 +------+ | | | | | | 133 |AppKey+--(LoRa)--+ +--(IP)--+ +---(RADIUS)---+ AppKey | 134 +------+ | | | | | | 135 +-------+ +-------+ +--------+ 136 End-Device Gateway Network Join 137 Server Server 138 (+ RADIUS client) (+ RADIUS server) 140 Figure 2: LoRAWAN Architecture with AAA and RADIUS authentication. 141 End-Device and RADIUS server have a shared secret - the AppKey, which 142 is used to derive the session keys (NwkSKey and AppSKey). 144 The document describes how LoRaWAN join procedure is integrated with 145 AAA infrastructure using RADIUS [RFC2865] by defining the new 146 attributes needed to support the LoRaWAN exchange. 148 1.1. Requirements Language 150 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 151 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 152 document are to be interpreted as described in RFC 2119 [RFC2119]. 154 2. LoRaWAN support in RADIUS 156 Regarding the overall functionality, the RADIUS LoRaWAN support 157 defines the new Attributes needed for the management of the join 158 procedure. The Network Server will implement a RADIUS client 159 supporting this specification and therefore, it MUST implement the 160 RADIUS attributes for this service. The NAS-Port-Type specifying the 161 type of port on which the Network Server is authenticating the End- 162 Device in this case MAY be 18 ( Wireless - Other ) or a new one 163 specifically assigned for LoRaWAN (TBD.). 165 3. LoRaWAN Overview 167 3.1. Introduction 169 The LoRAWAN specification defines how the MAC and PHY layer will be 170 used with the LoRa radio technologies. It defines a process by which 171 the smart objects can securely join the network in an authenticated 172 way and exchange application information ciphered and integrity 173 protected. The focus of this document is to extend how the process 174 of joining is performed by the specification including a AAA 175 infrastructure (RADIUS) to accomplish this. Next we review how the 176 keys, and each message is used in the joining procedure. Then we 177 elaborate some assumptions to design the integration of AAA in the 178 joining procedure possible. 180 3.2. LoRaWAN join procedure Key Material 182 The LoRaWAN specification describes 3 keys involved in the joining 183 procedure. One as a root key that will be used to generate the other 184 two, which will be used to secure the message exchanges after the 185 joining procedure success. The AppKey key used to derive the other 186 two keys, NwkSKey and AppSKey: 188 o The AppKey is an AES-128 application specific key assigned by the 189 owner of the application. This key is derived from an 190 application-specific root key that is only known to the 191 application owner and is stored in each device and in the Join 192 Server that will perform the authentication. 194 o The NwkSKey is a network session key that is specific to each End- 195 Device. It is shared between the Network Server and the End- 196 Device and used to calculate and verify the Message Integrity Code 197 (MIC) for each data message, between both entities. Furthermore, 198 it is used to cipher and decipher the payload of MAC-only data 199 message. 201 o The AppSKey is an application session key specific to each End- 202 Device. It is in charge of ciphering and deciphering the payload 203 of application-specific data messages and is also used to 204 calculate and verify the MIC that may be added to the payload of 205 application-specific data messages. 207 3.3. LoRaWAN joining procedure 209 The LoRaWAN joining procedure, as described in the LoRaWAN 210 Specification 1.0 [LoRaWAN], consists on one exchange. The first 211 message of this exchange is called join-request (JR) message and is 212 sent from the End-Device to the Network Server containing the AppEUI 213 and DevEUI of the End-Device with a nonce of 2 octets called 214 DevNonce. Figure 3 summarizes the format. 216 +-------------+-------------+-------------+ 217 Size (bytes) | 8 | 8 | 2 | 218 +---------------------------+-------------+-------------+ 219 Join Request | AppEUI | DevEUI | DevNonce | 220 +-------------+-------------+-------------+ 222 Figure 3: Join Request Message 224 In response to the join-request, the other endpoint will answer with 225 the join-accept (JA) (Figure 4) if the End-Device is successfully 226 authenticated and authorized to join the network. The join-accept 227 contains a nonce (AppNonce), a network identifier (NetID), an End- 228 Device address (DevAddr), a delay between the TX and RX (RxDelay) 229 and, optionally, the CFList (see LoRaWAN specification [LoRaWAN] 230 section 7). 232 +--------+-----+-------+----------+-------+-------------+ 233 Size (bytes)| 3 | 3 | 4 | 1 | 1 |16 (Optional)| 234 +-------------------------------------------------------------------+ 235 Join Accept |AppNonce|NetID|DevAddr|DLSettings|RxDelay| CFList | 236 +--------+-----+-------+----------+-------+-------------+ 238 Figure 4: Join Accept Message 240 Next, we enumerate and describe each field involved in the join 241 procedure message exchange. 243 o AppEUI: Global application ID in IEEE EUI64 to uniquely identify 244 the application provider. 246 o DevEUI: Global End-Device ID in IEEE EUI64 to uniquely identify 247 the End-Device 249 o DevNonce: A random value. 251 o AppNonce: A random value or some kind of unique ID provided by the 252 Network Server. 254 o NetID: A network identifier 256 o DevAddr: A 32 bit identifier of the End-Device in the current 257 network. It is composed of the Network ID and the Network 258 Address. 260 o DLSettings: 8 bits containing the down-link configuration. 262 o RxDelay: 8 bits containing the delay between TX and RX. 264 o CFList (Optional): Channel frequency list. 266 3.4. LoRaWAN Key Derivation 268 The keys NwkSKey and AppSKey are derived from the AppKey in both the 269 Join Server and the End-Device according to the LoRaWAN specification 270 [LoRaWAN] as follows: 272 Derivation of the NwkSkey: 274 NwkSKey = aes128_encrypt(AppKey, 0x01 | AppNonce | NetID | DevNonce | 275 pad16) 277 Derivation of the AppSkey: 279 AppSKey = aes128_encrypt(AppKey, 0x02 | AppNonce | NetID | DevNonce | 280 pad16) 282 Note: The pad16 function appends octets of containing "zero" so that 283 the length of the data is a multiple of 16. 285 4. Integration Overview 287 4.1. Mapping LoRaWAN Entities to AAA Infrastructure 289 In the current specification of LoRaWAN [LoRaWAN], there is no 290 explicit reference to an external entity to which the Network Server 291 can go to authenticate the End-Device. However, ongoing work related 292 to LoRaWAN, such as the work in the LoRa Alliance 293 [LoRaAllianceSecurity] sketches the use of a new entity, the Join 294 Server, that will be in charge of performing the authentication. 295 This separation of responsibilities is also the aim of our work, 296 where the Join Server acts as an external AAA server in a AAA 297 infrastructure using RADIUS as the protocol to communicate the 298 Network Server and the Join Server. Further, it is under 299 consideration the distribution of the AppSKey to a target application 300 server instead of the Network Server. Therefore, the Join Server 301 would need another protocol to deliver the AppSKey. Another RADIUS 302 interface could be used for this purpose, though this I-D focuses on 303 the joining procedure so far. 305 4.2. Assumptions 307 For the integration of LoRaWAN joining procedure with RADIUS next we 308 describe some assumptions regarding the LoRaWAN specification. The 309 first is that the AppKey is only shared between the AAA server (Join 310 Server) and the End-Device. The outcome of the successful join 311 procedure (i.e. NwkSKey and AppSKey) are sent from the AAA server to 312 the network-server. This allows for the End-Device to exchange 313 message with the network-server, once the join procedure is finished, 314 as specified in LoRaWAN [LoRaWAN]. 316 4.3. Protocol Exchange 318 The join procedure between the End-Device and the network-server 319 entails one exchange consisting on a join-request message and a join- 320 response message. In RADIUS the network-server implements a RADIUS 321 client to communicate with the Join Server, which act as AAA Server. 323 The protocol exchange is done in the following steps: 325 1. The End-Device sends the join-request message to to the Network 326 Server. 328 2. Upon reception of the LoRaWAN join-request message, the Network 329 Server creates a RADIUS Access-Request message, with the Join- 330 Request attribute containing the original message from the End- 331 Device, and the Join-Answer Attribute with all the fields of a 332 join-answer message except for the MIC, which will be calculated 333 by the AAA Server (Join Server), since is the one that holds the 334 AppKey. 336 3. Once the AAA Server authenticates and authorizes the End-Device, 337 sends back the Join-Answer with the MIC generated as specified by 338 the LoRaWAN specification. Furthermore, as a consequence of a 339 successful join procedure, the AppSKey (optional) and NwkSKey are 340 generated and sent along in AppSKey and NwkSKey Attributes 341 respectively. 343 4. The Network Server receives the Access-Accept (if successful), 344 obtains the content of the Join-Request attribute and sends it to 345 the End-Device, storing in association with that End-Device the 346 NwkSKey and the AppSKey. 348 AAA 349 End-Device Network Server Server (Join Server) 350 ----------- --------- ------- 351 | | | 352 1) | JR[MIC] | Access-Request | 353 |------------------------>| Join-Request Att | 354 | | Join-Answer Att* | 355 2) | |----------------------------------->| 356 | | | 357 | gen | | gen 358 | | | | | 359 | | | Access-Accept | | 360 | v | Join-Answer Att | v 361 | AppSKey | AppSKey Att* | AppSKey 362 3) | NwkSKey | NwkSKey Att | NwkSKey 363 | |<-----------------------------------| 364 | JA[MIC] | | 365 4) |<------------------------| | 366 | | | 368 Figure 5: Protocol 370 4.3.1. Join-Request Attribute 372 Description 374 This Attribute contains the original Join-Request message. This 375 attribute will only appear in the Access-Request message. A summary 376 of the Join-Request attribute format is shown below. The fields are 377 transmitted from left to right. 379 0 1 2 380 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 381 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 382 | Type | Length | String... 383 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 385 Type 387 TBD. for Join-Request 389 Length 391 18 393 String 395 The String field contains an octet string with the Join-Request 396 message as received over the network, such as defined in [LoRaWAN]. 398 4.3.2. Join-Answer Attribute 400 Description 402 This Attribute is used in both RADIUS Access-Request and RADIUS 403 Access-Accept messages. In the first case, it contains the Join 404 Answer message with all the needed values filled by the network- 405 server except the MIC (this fact is marked with an *). With these 406 values, the Join Server (AAA server) that holds the AppKey is able to 407 create the MIC and compose the final Join Answer message. In the 408 second case, it contains the Join Answer with the MIC generated by 409 the Join Server (AAA server). A summary of the Join-Answer attribute 410 format is shown below. The fields are transmitted from left to 411 right. 413 0 1 2 414 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 415 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 416 | Type | Length | String... 417 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 419 Type 421 TBD. for Join-Answer 423 Length 425 28 427 String 429 The String field contains an octet string with the Join-Answer as 430 received over the network , as defined in [LoRaWAN]. 432 4.3.3. AppSKey Attribute 434 Description 436 This Attribute contains the AppSKey, an application session key 437 specific for the End-Device. This attribute is optional, and will 438 only appear in the RADIUS Access-Accept message. A summary of the 439 AppSKey attribute format is shown below. The fields are transmitted 440 from left to right. 442 0 1 2 443 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 444 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 445 | Type | Length | String... 446 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 448 Type 450 TBD. for AppSKey 452 Length 454 16+ 456 String 457 The String field contains an octet string containing the Application 458 Session Key, as defined in [LoRaWAN]. 460 4.3.4. NwkSKey Attribute 462 Description 464 This Attribute contains the NwkSKey, an network session key specific 465 for the End-Device. This attribute will only appear in the Access- 466 Accept message. A summary of the NwkSKey attribute format is shown 467 below. The fields are transmitted from left to right. 469 0 1 2 470 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 471 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 472 | Type | Length | String... 473 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 475 Type 477 TBD. for NwkSKey 479 Length 481 16+ 483 String 485 The String field contains the octet string of the Network Session Key 486 , as defined in [LoRaWAN]. 488 4.3.5. Table of Attribute 490 Request Accept Reject Challenge # Attribute 491 1 0 0 0 TBD. Join-Request 492 1 1 0 0 TBD. Join-Answer 493 0 0-1 0 0 TBD. AppSKey 494 0 1 0 0 TBD. NwkSKey 495 Request Accept Reject Challenge # Attribute 497 Figure 6: Attributes Table 499 5. Open Issues 501 With the purpose of extending the authentication process via AAA 502 infrastructures, and concretely, RADIUS, we have faced a question 503 regarding the relationship between the AppEUI associated to the 504 organization operating the Join Server and the realm used by RADIUS 505 to route the AAA information to the AAA Server (Join Server) of that 506 organization. 508 In particular, the Network Server knows the AppEUI included in the 509 Join Request, but it needs to discover the realm (Fully Qualified 510 Domain Name) that corresponds to that organizations ID to be able to 511 communicate with the concrete RADIUS server. 513 NOTE: One option MAY be to use the DNS system to provide the FQDN 514 associated to an AppEUI (which is an EUI64 address). The mapping 515 using DNS to find out the domain name associated to an EUI64 address 516 has been described in [RFC7043]. However, we would need the inverse 517 process. Nevertheless, this needs further discussion. 519 6. Security Considerations 521 In the LoRaWAN 1.0 specification, the AppSKey and NwkSKey are not 522 sent over the network, they are derived in each of the endpoints that 523 communicate, namely the End-Device and the Network Server. In this 524 document we propose relegating the responsibility of deriving the 525 Network Session Key and Application Session Key to the RADIUS server 526 (the Join Server). These session keys need to be sent to the Network 527 Server and if necessary to the application server. 529 To send the messages over the network between the RADIUS server and 530 the RADIUS client (in this case the Network Server). How to provide 531 confidentiality to the key distributed is outside the scope of this 532 document, nevertheless RadSec (RFC6614) or extensions such as those 533 defined in RFC 6218 may be considered to protect the distribution. 535 The AAA framework and its key management features become increasingly 536 important as the use case of LoRaWAN adds functionality and 537 complexity. This is the case for having the Application Server and 538 Network Server as separate entities and each receive its keys. 539 Although the utility is apparent in that specific case, it has to be 540 considered in any other future use-case that may require key 541 management and key distribution. Another point in favor of using AAA 542 can be also appreciated since the modifications required by this 543 proposal does not imply the modification of the protocols of the 544 constrained link, but the unrestricted network that is used to manage 545 LP-WAN. 547 7. Proof of concept implementation 549 The proof of concept is implemented using the Go programming 550 language, that is well suited for the development of web servers or a 551 network servers as in this case. 553 The implementation of the network server is from [LoRaSERVER] which 554 is tailored with the features of a RADIUS Client and the RADIUS 555 server implementation from [RADIUSGo] that is modified to handle 556 LoRaWAN attributes. 558 The LoRa end-device, pre-configured with AppKey, from Nemeus [MK002] 559 is a USB key that can be controlled by UART (AT command) through USB 560 interface. A JAVA application installed on a Linux machine is used 561 to send control and data messages from the End-Device. 563 The LoRa Gateway is from EXPEMB [EXPEMB] which uses the packet 564 forwarder to forward the LoRa packets to the LoRa Network Server. 565 The Network Server is run in a docker container on a Linux machine 566 transfers the LoRa packets into the RADIUS attributes to be sent to 567 the RADIUS server. For now, the packets are sent to the default 568 RADIUS server but in the future this would be changed as per the 569 discussion in Section 5 in order to redirect the RADIUS request to 570 appropriate RADIUS server. 572 The RADIUS server is run in a docker container on a Linux machine 573 which contains the mapping between the DevEUI of the End-Device and 574 the AppKey. This AppKey from the map along with the received LoRa 575 attributes is used to derive the session keys, NwkSKey and AppSKey, 576 in the RADIUS server. These keys are transported as RADIUS 577 attributes back to the network server. 579 +----------+ +---------+ +-------------+ +---------+ 580 | | | LoRa | | Nwk server/ | | Radius | 581 |End-device+---------+ Gateway +----------+ RADIUS +--------+ Server | 582 | | LoRa | | IP | client | IP | | 583 +----------+ +---------+ +-------------+ +---------+ 585 A successful authentication would result in the session keys, NwkSKey 586 and AppSKey, being visible on the network server that can be viewed 587 using a web interface and the DevAddr being acquired by the End- 588 Device from the Join Accept Lora message. Running Wireshark on the 589 interface between RADIUS server and the Network Server shows the 590 RADIUS packets with the LoRa attributes. 592 To simplify the design and implementation, we opted for creating one 593 RADIUS Attribute per message, instead of per each field within the 594 message since only the authenticating module responsible for the Join 595 Procedure in the current network server is delegated to the AAA 596 server and the AAA server would be able to obtain the required fields 597 from this single attribute, i.e either JoinRequest or JoinAccept 598 message. This design choice would follow the RADIUS guidelines given 599 in [RFC6158] identifying it as string for being an opaque 600 encapsulation of data structures defined outside RADIUS. Creating an 601 attribute per field, would be useful in case the AAA infrastructure 602 would change its behavior depending on the specific content of one or 603 more of the fields contained in the message. This could be the case 604 when the LoRaWAN use case becomes more complex and add more 605 functionality. 607 As future work, we intend to implement the proof of concept in 608 FreeRADIUS 610 8. Acknowledgments 612 This work has been possible partially by the SMARTIE project 613 (FP7-SMARTIE-609062 EU Project) and the Spanish National Project 614 CICYT EDISON (TIN2014-52099-R) granted by the Ministry of Economy and 615 Competitiveness of Spain (including ERDF support). 617 We also wanted to thank for the comments received about this document 618 by Sri Gundavelli, Yeoh Chun-Yeow, Alan DeKok, Stephen Farrell and 619 Mark Grayson. 621 9. IANA Considerations 623 In this document we define 4 new RADIUS Attributes that would need 624 actions from IANA to assign the corresponding numbers. 626 +--------+--------------+----------------------------+ 627 | Number | Name | Reference | 628 +----------------------------------------------------+ 629 | TBD | Join-Request | Section 4 of this document | 630 | TBD | Join-Answer | Section 4 of this document | 631 | TBD | AppSKey | Section 4 of this document | 632 | TBD | NwkSKey | Section 4 of this document | 633 +--------+--------------+----------------------------+ 635 10. References 636 10.1. Normative References 638 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 639 Requirement Levels", BCP 14, RFC 2119, 640 DOI 10.17487/RFC2119, March 1997, 641 . 643 [RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, 644 "Remote Authentication Dial In User Service (RADIUS)", 645 RFC 2865, DOI 10.17487/RFC2865, June 2000, 646 . 648 [RFC6158] DeKok, A., Ed. and G. Weber, "RADIUS Design Guidelines", 649 BCP 158, RFC 6158, DOI 10.17487/RFC6158, March 2011, 650 . 652 [RFC7043] Abley, J., "Resource Records for EUI-48 and EUI-64 653 Addresses in the DNS", RFC 7043, DOI 10.17487/RFC7043, 654 October 2013, . 656 10.2. Informative References 658 [EXPEMB] EXPEMB, E., "LoRa MultiConnectivity Service Gateway - Last 659 Accessed:", July 2016, . 663 [LoRaAllianceSecurity] 664 Girard, P., "LoRaWAN - SECURITY a comprehensive insight - 665 Online Resource: Last Accessed", July 2016, 666 . 670 [LoRaSERVER] 671 Acklio, A., "LoRa Server", July 2016, 672 . 674 [LoRaWAN] Sornin, N., Luis, M., Eirich, T., and T. Kramp, "LoRa 675 Specification V1.0", January 2015, . 679 [MK002] Nemesus, N., "MK002-xx-EU - Last Accessed:", July 2016, 680 . 682 [RADIUSGo] 683 bronze1man, B., "Radius: A golang radius library - Last 684 Accessed:", July 2016, . 687 Authors' Addresses 689 Dan Garcia-Carrillo (Ed.) 690 University of Murcia 691 Campus de Espinardo S/N, Faculty of Computer Science 692 Murcia 30100 693 Spain 695 Phone: +34 868 88 78 82 696 Email: dan.garcia@um.es 698 Rafa Marin-Lopez 699 University of Murcia 700 Campus de Espinardo S/N, Faculty of Computer Science 701 Murcia 30100 702 Spain 704 Phone: +34 868 88 85 01 705 Email: rafa@um.es 707 Arunprabhu Kandasamy 708 Acklio 709 2bis rue de la Chataigneraie 710 35510 Cesson-Sevigne Cedex 711 France 713 Email: arun@ackl.io 715 Alexander Pelov 716 Acklio 717 2bis rue de la Chataigneraie 718 35510 Cesson-Sevigne Cedex 719 France 721 Email: a@ackl.io