Internet Engineering Task Force B. Wang, Ed. Internet-Draft S. Zhou, Ed. Intended status: Standards Track Hikvision Expires: 21 September 2022 C. Li, Ed. Guangzhou University C. Wu, Ed. Z. Wang, Ed. Zhejiang University 20 March 2022 Open Service Access Protocol for IoT Smart Devices draft-wang-open-service-access-protocol-02 Abstract With the development of IoT(Internet of Things) technology, everything is interconnected. Mass IoT data, devices, businesses, and services adopt different data descriptions and service access methods, resulting in fragmentation issues, such as data heterogeneous, device heterogeneous, and application heterogeneous, which hinders the development of the industry. In order to solve the problem, this draft proposes the requirements for IoT smart devices to transmit and control, as well as transmission and protocol interfaces. It is for the program design, system testing and acceptance, and related research. Structured, unified, and standardized open service interconnection model reduces business replication cost and removes service barriers to push industrial development. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on 21 September 2022. Wang, et al. Expires 21 September 2022 [Page 1] Internet-Draft Open Service Access Protocol for IoT March 2022 Copyright Notice Copyright (c) 2022 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/ license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. requirements for Consistency . . . . . . . . . . . . . . . . 3 2.1. Terms and Definitions . . . . . . . . . . . . . . . . . . 3 2.1.1. Area . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1.2. Attribute . . . . . . . . . . . . . . . . . . . . . . 4 2.1.3. Operation . . . . . . . . . . . . . . . . . . . . . . 4 2.1.4. Event . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1.5. Resource . . . . . . . . . . . . . . . . . . . . . . 4 2.1.6. IoT Device Management Platform . . . . . . . . . . . 4 2.1.7. Load Balancing Service . . . . . . . . . . . . . . . 4 2.1.8. Device Access Service . . . . . . . . . . . . . . . . 4 2.1.9. Picture Service . . . . . . . . . . . . . . . . . . . 5 2.1.10. Video Service . . . . . . . . . . . . . . . . . . . . 5 2.1.11. Event Service . . . . . . . . . . . . . . . . . . . . 5 2.1.12. IoT Smart Devices . . . . . . . . . . . . . . . . . . 5 2.2. Abbreviations and Acronyms . . . . . . . . . . . . . . . 5 3. Framework of Device Communication Protocol . . . . . . . . . 5 4. Interface protocol structure . . . . . . . . . . . . . . . . 6 5. Device certification . . . . . . . . . . . . . . . . . . . . 7 6. Get access service . . . . . . . . . . . . . . . . . . . . . 15 7. Registration and Deregistration . . . . . . . . . . . . . . . 16 8. Heartbeat . . . . . . . . . . . . . . . . . . . . . . . . . . 17 9. Security Considerations . . . . . . . . . . . . . . . . . . . 17 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 11. Informative References . . . . . . . . . . . . . . . . . . . 18 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 Wang, et al. Expires 21 September 2022 [Page 2] Internet-Draft Open Service Access Protocol for IoT March 2022 1. Preface With the development of the IoT technology, everything is widely interconnected, human-machine interact deep, including autonomous vehicles, telemedicine, smart factories, smart cities and other innovative applications. With the development of business, Mass IoT data, devices, businesses, and services adopt different data descriptions and service access methods, resulting in fragmentation issues, such as data heterogeneous, device heterogeneous, and application heterogeneous, which hinders the development of the industry, which mainly refers to: 1. Low value of data: IoT data has the characteristics of multi- source heterogeneity and huge scale, making it difficult for data analysis and sharing. At the same time, the lack of business relevance between massive amounts of data leads to inefficient use of data. 2. High cost of business replication: different devices use different access standards. The cost of device access is too high and the time is too long. With the growth quantity of applications and devices, new device needs to be customized and developed multiple times for different standards, resulting in increased business replication cost. 3. Difficulty in industrial chain cooperation: There are different access protocols and data models between different manufacturers. The internal industrial chain has its own system, which makes it difficult for industrial chain to collaborate, for devices to be linked, maintained, for service to be compatible, Which seriously affects the user experience. In order to solve the problem, this draft proposes the requirements for IoT smart devices to transmit and control, as well as transmission and protocol interfaces. It is for the program design, system testing and acceptance, and related research. Structured, unified, and standardized open service interconnection model reduces business replication cost and removes service barriers to push industrial development. 2. requirements for Consistency 2.1. Terms and Definitions 2.1.1. Area A set of related functions, which is business independent. Wang, et al. Expires 21 September 2022 [Page 3] Internet-Draft Open Service Access Protocol for IoT March 2022 2.1.2. Attribute Used to describe the sustainable state of the devices during operation, which can be read and set. 2.1.3. Operation A method that can be called externally by a device or platform. The operation includes "input parameters" and "output parameters". The input parameters are the instruction information that needed to perform the operation, and the output parameters are the feedback information after the instruction is executed. 2.1.4. Event Information actively reported by the device. This type of information needs to be reported in real time and processed by the platform in time. If the device network is interrupted, it can be cached and reported after recovery. 2.1.5. Resource An entity that is a relatively independent component of the device and can independently handle user requirements. User applications can independently show or manage the resources of the device. For example, the video channel of NVR device. 2.1.6. IoT Device Management Platform A system that connects a large number of diverse and heterogeneous sensing devices and can unify access management of devices, collect, process and store data. 2.1.7. Load Balancing Service Responsible for equipment certification. The device actively authenticates to the load balancing service. After passing the authentication, the device will balance the load to multiple devices to access the service through redirection. 2.1.8. Device Access Service Services for managing, controlling and configing device functions and support attributes, operations, and events. Wang, et al. Expires 21 September 2022 [Page 4] Internet-Draft Open Service Access Protocol for IoT March 2022 2.1.9. Picture Service Responsible for image storage services, support upload, download images and other functions. 2.1.10. Video Service Responsible for media data transmission, support real-time preview, video playback, voice intercom and other functions. 2.1.11. Event Service Responsible for receiving and handling events. 2.1.12. IoT Smart Devices Physical entities with video, image, and information perception capabilities, including: video equipment, access control, radar, etc. It can be directly connected to the IoT device management platform, or be a gateway that connects the agent sub-device and the IoT device management platform. 2.2. Abbreviations and Acronyms +============================+=====================================+ | Abbreviations and Acronyms | Full Name | +============================+=====================================+ | IP | Internet Protocol | +----------------------------+-------------------------------------+ | JSON | Java Script Object Notation | +----------------------------+-------------------------------------+ | MQTT[MQTT2016] | Message Queuing Telemetry Transport | +----------------------------+-------------------------------------+ | TLS[RFC8446] | Transport Layer Security | +----------------------------+-------------------------------------+ | UTF-8 | 8-bit Unicode Transformation Forma | +----------------------------+-------------------------------------+ | URL | Uniform Resoure Locator | +----------------------------+-------------------------------------+ Table 1: Abbreviations and Acronyms 3. Framework of Device Communication Protocol The framework of the protocol is shown below: Wang, et al. Expires 21 September 2022 [Page 5] Internet-Draft Open Service Access Protocol for IoT March 2022 Bussiness Protocol-------------------------------------------+ | +------+ +-----+ +-------+ +----+ +--------+ | | | | | | | | |area| |Resource| | | |store/| |Media| |Upgrate| +----+ +--------+ | | |file | | | | | +---------+ +---------+ +-----+ | | | | | | | | |attribute| |operation| |event| | | +------+ +-----+ +-------+ +---------+ +---------+ +-----+ | +------------------------------------------------------------+ Fundamental communication protocol---------------------------+ | +---------------------------+ | | | +-----------------------+ +----------------------------+ | | | | store | media |update | | attribute|operation| event | | | | |channel|channel|channel| | channel | channel |channel| | | | +-----------------------+ +----^-----+----^---------^--+ | | +---------------------------+ | | | | | ^ ^ ^ | | | | | | | +---+---------+----------+---------+--+ | | | | | MQTT | | | | | +-----------------^---------------^---+ | | | | | | | | | | | +----+---+ | | | | | | TLS | | | | | | +----^---+ | | | | | | | | +---+---+ +--+---------------------+---------------+---+ | | |HTTP(S)| | TCP | | | +-------+ +--------------------------------------------+ | +------------------------------------------------------------+ Figure 1: Framework of Device Communication Protocol The business is separated from the protocol. In the bottom layer, it adopts MQTT to transmit data. Different transmission channels are used for authentication, media, storage and attributes, operations, and events. 4. Interface protocol structure In this draft, the session channel interface adopts MQTT protocol. Structure of MQTT protocol is divided into three sections: fixed header, variable header and payload. Structure of MQTT protocol is shown below. Wang, et al. Expires 21 September 2022 [Page 6] Internet-Draft Open Service Access Protocol for IoT March 2022 --------+---------------------------+----------------------------------- | | | Header | Payload structre|------------+--------------+----------------+------------------ | | | | |Fixedheader |Variableheader|GeneralPayload |ApplicationPayload --------+------------+--------------+-------+--------+------------------ name |Fixedheader |Variableheader|length |content |content --------+------------+--------------+-------+--------+------------------ symbol |FixedHEADER |VariableHEADER|LEN |Gernal |Func --------+------------+--------------+-------+--------+------------------ length |2-5 bytes |variable |2 bytes|variable|variable --------+------------+--------------+-------+--------+------------------ des- |Depending |Different |The |See |The format cription|on the |control |length |defi- |depends on |length of |message has |of |nition |specific |the variable|different |general|for its |transaction |header and |variable |payload|format | |payload, the|headers | | | |length of | | | | |the fixed | | | | |header | | | | |varies | | | | |between 2 | | | | |and 5 bytes | | | | --------+------------+--------------+-------+--------+------------------ Figure 2: MQTT protocol structure General protocols and business protocol bodies need AES (128) encryption during transmission, and UTF-8 encoding is used uniformly for character strings. 5. Device certification The overall protocol format of the authentication process is shown as follows: Wang, et al. Expires 21 September 2022 [Page 7] Internet-Draft Open Service Access Protocol for IoT March 2022 --------+--------------------------+------------------------------------ | | | Header | Payload structre|-----------+--------------+-----------------+------------------ | | | | |Fixedheader|Variableheader|GeneralPayload |ApplicationPayload --------+-----------+--------------+---------+-------+------------------ name |Fixedheader|Variableheader|version |con+ | | | | |tent | --------+-----------+--------------+---------+-------+------------------ symbol |FixedHEADER|VariableHEADER|PROTOCOL-| |PROTOCOL- | | |VERSION |Func |VERSION | | | | | --------+-----------+--------------+---------+-------+------------------ length |2|5 bytes |Variable |3 bytes |Va- |3 bytes | | | |riable | | | | | | --------+-----------+--------------+---------+-------+------------------ des- |Depending |Different |The |See |The cription|on the |control |version |tran- |version |length of |message has |of |saction|of |the |different |protocol |for its|protocol |variable |variable | |format | |header and |headers | | | |payload, | | | | |the | | | | |length of | | | | |the fixed | | | | |header | | | | |varies | | | | |between 2 | | | | |and 5 bytes| | | | --------+-----------+--------------+---------+-------+------------------ Figure 3: MQTT protocol format The protocol version definition is shown as follows: Wang, et al. Expires 21 September 2022 [Page 8] Internet-Draft Open Service Access Protocol for IoT March 2022 +===================+======+=======================================+ | name | type | description | +===================+======+=======================================+ | FORM_VERSION | char | version number of protocol form | +-------------------+------+---------------------------------------+ | HIGH_TYPE_VERSION | char | version number of protocol type(high) | +-------------------+------+---------------------------------------+ | LOW_TYPE_VERSION | char | version number of protocol type(low) | +-------------------+------+---------------------------------------+ Table 2: Protocol version definition Device access adopts bidirectional negotiation protocol process. Devices sends the supported type of protocol group to the balance load service, and the server will determine which way to communicate depending on its own situation. After the device being authenticated, it can establish an MQTT connection with the device access service (Das) through the sessionkey to communicate with the bussiness protocol. The specific bidirectional negotiation diagram is as follows: Wang, et al. Expires 21 September 2022 [Page 9] Internet-Draft Open Service Access Protocol for IoT March 2022 +------+ +------+ |device| |server| +---+--+ +------+ | | | | | | | | +----------------------+----------+ | | | negotiation request | | | | +----------------------+ | +--negotiation request---> +--+ | Control message type:0x1 | | | | | | | | | | Control flag:0x1 | | | | | | | | | | protocol type:1 | | | | | | | | | | protocol group:(1,2,4,8) | | | | | | | <--negotiation response--+ | | transaction content:xxxxxx | | | | +---------------------------------+ | +--+ | | | | +----------------------+----------+ | | | negotiation response | | | | +----------------------+ | | | | Control message type:0x2 | | | | | | | | Control flag:0x1 | | | | | | | | protocol type:1 | | | | | | | | transactionocontent:xxxxxx | | | +---------------------------------+ | | Figure 4: bidirectional negotiation diagram - consistence Wang, et al. Expires 21 September 2022 [Page 10] Internet-Draft Open Service Access Protocol for IoT March 2022 +------+ +------+ |device| |server| +---+--+ +------+ +----------------+-+ | | +----------------+-+ | negotiation | | | | | negotiation | | | request2 | | | | | response2 | | +----------------+ | | negotiation | +----------------+ | |Control | +-- request1 --> | |Control | |message type:0x1 | | | |message type:0x2 | | | | | | | |Control flag:0x1 | | | |Control flag:0x1 | | | | | | | |protocol type:2 | | | |protocol type:2 | | | | | | | |protocol | | negotiation | |protocol | |group:(1,2,4,8) | | <-- response1--+ |group:(2,4,8) | | | | | | | |transaction | | | |transaction | |content:xxxx | | | |content:xxxx | +------------------+ | | +------------------+ | | +------------------------------------------------------------------+ | negotiation | disconnect +-- request2 --> | | | +----------------+-+ | | +----------------+-+ | negotiation | | | | | negotiation | | | request2 | | | | | response2 | | +----------------+ | | | +----------------+ | |Control | | | |Control | |message type:0x1 | | negotiation | |message type:0x2 | | | | <-- response2--+ | | |Control flag:0x1 | | | |Control flag:0x1 | | | | | | | |protocol type:2 | | | |protocol type:2 | | | | | | | |protocol | | | |transaction | |group:(1,2,4,8) | | | |content:xxxx | | | | | | | |transaction | | | | | |content:xxxx | | | | | +------------------+ | | +------------------+ | | | | + + Figure 5: bidirectional negotiation diagram - inconsistence Wang, et al. Expires 21 September 2022 [Page 11] Internet-Draft Open Service Access Protocol for IoT March 2022 bidirectional negotiation can be divided into two conditions: (1) If the service supports this type of protocol, select the most secure protocol in the device's protocol group to complete the negotiation and communicate with the device; (2) If the service does not support the type of protocol, return the message to the device,which contains the type of protocol and protocol group supported by the service. And then, interupt TCP connection. If the device supports it, use again the type of protocol and protocol group supported by the service to go through the authentication process. Otherwise, the device should give up authentication with the service. In order to ensure forward compatibility with the ECDH key interaction mode, Bit1 of the control flag bit is enabled. When Bit1 is 0, the control message type remains in the original mode, and when Bit1 is 1, it means that the ECDH key mode is used for interaction. The key algorithm of secret key in the authentication process: sharekey:pdkdf2_SHA256(md5(md5(MD5(verification code + device serial number)+www.88075998.com))) Device masterkey: ecdh_NID_secp384r1 (lbs_publickey, device_privatekey) Server masterkey: ecdh_NID_secp384r1 (device_publickey, lbs_privatekey) a) First Authentication When the device requires for working online the first time, useexchange algorithm of ECDH secret key to initialize DEVID and MasterKey. The process is shown as follows: Wang, et al. Expires 21 September 2022 [Page 12] Internet-Draft Open Service Access Protocol for IoT March 2022 +------+ +-----------+ |Device| |Lbs service| +------+ +------+----+ | | +-----------------Privatekey exchange------------------------+ +-----+ | | |Generate privatekey and publickey | <-----+ | +-----+ | | |Generate sharekey | <-----+ | |-------Request for privatekey interaction-------> <-------Reponse for privatekey interaction-------+ +-----+ | | |Decrypt lbs_publickey from response | <-----+ | +-----+ | | |Generate materkey | <-----+ | +-------------------- apply devid---------------------------+ |-------| Request for applying devid |-----------> <---------Reponse for applying devid-------------+ +-----+ | | |Decrypt devid and sessionkey from response| <-----+ | |---|Request for getting Das service address-----> <----Reponse for getting Das service address-----+ | | + + Figure 6: First Authentication b) Reauthentication When the device is disconnected and ask for reauthenticated, it needs to request reauthentication from the platform and update the sessionkey. The specific process is shown as follows: Wang, et al. Expires 21 September 2022 [Page 13] Internet-Draft Open Service Access Protocol for IoT March 2022 +------+ +-----------+ |Device| |Lbs Service| +------+ +-----+-----+ | | +-------------------------------------------------------------+ +------+ Update request for sessionkey +----------> | | <------+ Update respond for sessionkey +----------+ | | +-----+ | | Decrypt sessionkey | | | from response | <-----+ | +-------------------------------------------------------------+ | | +---------+ Get service address request +---------> | | <---------+ Get service address response +--------+ | | Figure 7: Re-authenticate c) Define the ECDH control message type as follows: Wang, et al. Expires 21 September 2022 [Page 14] Internet-Draft Open Service Access Protocol for IoT March 2022 +============+=======+================================+=============+ |message |control| name | description| |direction |message| | | +============+=======+================================+=============+ |Dev<--->Lbs |0x1 | Authentication_ECDH_Req | request for| | | | |ECDH exchange| +------------+-------+--------------------------------+-------------+ |Dev<--->Lbs |0x2 | Authentication_ECDH_Rsp | response for| | | | |ECDH exchange| +------------+-------+--------------------------------+-------------+ |Dev<--->Lbs |0x3 | Rsrv | reserve| +------------+-------+--------------------------------+-------------+ |Dev<--->Lbs |0x4 | Refresh_SessionKey_Req | refresh| | | | | SessionKey| | | | | request| +------------+-------+--------------------------------+-------------+ |Dev<--->Lbs |0x5 | Rsrv | reserve| +------------+-------+--------------------------------+-------------+ |Dev<--->Lbs |0x6 | Refresh_SessionKey_Rsp | refresh| | | | | SessionKey| | | | | response| +------------+-------+--------------------------------+-------------+ |Dev<--->Lbs |0x7 | Authentication_apply_devid_Req | request| | | | | device ID| +------------+-------+--------------------------------+-------------+ |Dev<--->Lbs |0x8 | Authentication_apply_devid_Rsq | response| | | | | device ID| +------------+-------+--------------------------------+-------------+ |Dev<--->Lbs |0x9 | Authentication_apply_devid_Cfm | confirm| | | | | device ID| +------------+-------+--------------------------------+-------------+ Table 3: Protocol version definition 6. Get access service As the number of device accesses increases, there will be bottlenecks in the performance of single-node accesses, so the platform needs to support the mode of multiple device accesses. To support this mode, the devices are redirected to multiple access services by load balancing server. After the device obtains the sessionKey through two-way authentication, it initiates a request for access service within the same TCP connection, and the message in the request is encrypted with the sessionKey. Wang, et al. Expires 21 September 2022 [Page 15] Internet-Draft Open Service Access Protocol for IoT March 2022 +------------+ +-------------+ +------+ |Balance load| |Device access| |Device| | ser^ice | | service | +------+ +------+-----+ +------+------+ | | | Redirect---------------------------------+ | | +--- F1:Request for getting a -----> | | | | device access service address | | | | | | | | | <--- F2:Return a device access ----+ | | | | ser^ice information | | | +----------------------------------------+ | | | | Bussiness-----------------------------------------------------+ | | | | | | <------- Business message:AES128(message)----------> | | | AES128 privatekey:sessionkey | | | | | | | +-------------------------------------------------------------+ Figure 8: Get access service 7. Registration and Deregistration After the device completes two-way authentication to obtain a specific access service address, the device initiates a request to register online through the MQTT protocol, and the application message body in the request is encrypted using the sessionKey obtained by two-way authentication. +-------------+ +------------+ | Device | | Platform | |(MQTT Client)| |(MQTT Sever)| +-----+-------+ +------+-----+ | | +------- F1:Device register and login(MQTT CONNECT) -------> | | <-------- F2:Register and respond(MQTT CONNACK) -----------+ | | <---------------- Business interaction --------------------> | | +---- F3:Send request for disconnect(MQTT DISCONNECT) -----> | | + + Figure 9: Registration and Deregistration Wang, et al. Expires 21 September 2022 [Page 16] Internet-Draft Open Service Access Protocol for IoT March 2022 a) F1: After the device and platform network connection is established, the device sends a online request to the platform via MQTTCONNECT, of which payload contains one or more encoded fields, including: unique identifier of the client, Will subject, Will message, username and password. b) F2: The platform returns the response message to the device via MQTTCONNACK to inform it whether it succeeded or not; c) F3: Before disconnecting, the device sends a DISSCONNECT message to the platform, indicating that it wants to disconnect normally, and the platform will close the TCP/IP connection after receiving the request. 8. Heartbeat After the device has registered with the platform, it needs to send heartbeat requests periodically according to the heartbeat interval indicated in the registration request. The interval is usually 30s. Used for: a) Inform the platform that the device is alive when no other control messages are sent from the device to the platform b) Request the platform to send a response confirming that it is alive. c) Use the network to confirm that the network connection is not disconnected. +------+ +--------+ |Device| |Platform| +------+ +----+---+ | | +------ F1: Send a heartbeat request(MQTT PINGREQ) -----------> | | <--- F2: Respond to the heartbeat request MQTT PINGRESP) -----+ | | Figure 10: Heartbeat 9. Security Considerations This entire memo deals with security issues. Wang, et al. Expires 21 September 2022 [Page 17] Internet-Draft Open Service Access Protocol for IoT March 2022 10. IANA Considerations This documents has no IANA actions. 11. Informative References [MQTT2016] ISOIEC, "Information technology - Message Queuing Telemetry Transport", . [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", DOI 10.17487/RFC8446, August 2018, . Authors' Addresses Bin Wang (editor) Hikvision 555 Qianmo Road, Binjiang District Hangzhou 310051 China Phone: +86 571 8847 3644 Email: wbin2006@gmail.com Shaopeng Zhou (editor) Hikvision 555 Qianmo Road, Binjiang District Hangzhou 310051 China Phone: +86 571 8847 3644 Email: zhoushaopeng@hikvision.com Chao Li (editor) Guangzhou University 230 Wai Huan Xi Road Guangzhou 510006 China Email: lichao@gzhu.edu.cn Chunming Wu (editor) Zhejiang University 866 Yuhangtang Rd Wang, et al. Expires 21 September 2022 [Page 18] Internet-Draft Open Service Access Protocol for IoT March 2022 Hangzhou 310058 China Email: wuchunming@zju.edu.cn Zizhao Wang (editor) Zhejiang University 866 Yuhangtang Rd Hangzhou 310058 China Email: 22021272@zju.edu.cn Wang, et al. Expires 21 September 2022 [Page 19]