Internet DRAFT - draft-zhang-t2trg-accident-blockchain

draft-zhang-t2trg-accident-blockchain







Network Working Group                                              R. Li
Internet-Draft                                             X. Zhang, Ed.
Intended status: Informational                                    J. Fan
Expires: July 2, 2021                          Inner Mongolia University
                                                       December 29, 2020


   Architecture for collecting traffic accident information based on
                               blockchain
                draft-zhang-t2trg-accident-blockchain-00

Abstract

   Blockchain is a distributed technology, and it uses cryptography and
   hash functions to store data in a chain to ensure that data are
   tamper-resistant and traceable.  So, this document proposes an
   architecture for collecting traffic accident information based on
   blockchain.  At the same time, this document describes the working
   method of collecting traffic accident information under this
   architecture.

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   to this document.  Code Components extracted from this document must
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Relate work . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  System structure  . . . . . . . . . . . . . . . . . . . . . .   5
     3.1.  Perception layer  . . . . . . . . . . . . . . . . . . . .   6
     3.2.  Edge computing layer  . . . . . . . . . . . . . . . . . .   6
     3.3.  Service layer . . . . . . . . . . . . . . . . . . . . . .   6
   4.  Scheme design . . . . . . . . . . . . . . . . . . . . . . . .   7
     4.1.  Traffic accident information query  . . . . . . . . . . .   7
     4.2.  Traffic accident information return . . . . . . . . . . .   7
       4.2.1.  Resource fragmenting method . . . . . . . . . . . . .   7
       4.2.2.  Resource Naming Method  . . . . . . . . . . . . . . .   8
     4.3.  RSUs consensus  . . . . . . . . . . . . . . . . . . . . .   8
     4.4.  Traffic accident information storage  . . . . . . . . . .   9
   5.  Discuss . . . . . . . . . . . . . . . . . . . . . . . . . . .  10
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   8.  Conclusion  . . . . . . . . . . . . . . . . . . . . . . . . .  10
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  11
   10. Informative References  . . . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

   With the development of society, there are more and more vehicles on
   the road, and a problem that follows is that the incidence of traffic
   accidents is also increasing.  The frequent occurrence of traffic
   accidents has brought a serious impact on human life, and has brought
   certain pressure on the relevant traffic departments to deal with
   traffic accidents.  The handling of traffic accidents must be timely,
   and the evidence must be obtained correctly, so as to avoid traffic
   jams, secondary accidents and legal disputes.  Therefore, how to use
   the existing technology to quickly, correctly and effectively deal
   with traffic accidents has become a very important issue.

   The most important thing to deal with traffic accidents is to collect
   traffic accident information (also known as "resources").  At
   present, the main methods of collecting traffic accident information
   are manual and automatic.  Among them, manual methods include
   measuring tape, witness investigation, and on-site photographing.
   The automatic method is to use the camera at the intersection.  These
   methods require a long time, and cause certain difficulties for rapid



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   recording, rapid evacuation of traffic, subsequent accident analysis
   and liability determination.

   In the past few years, with the development of wireless communication
   technology and the automobile industry, the Vehicular Ad Hoc Network
   (VANET) has developed significantly [Misra2009].  Based on the VANET
   researchers have proposed a large number of related applications,
   which are divided into safety-related applications and comfort-
   related applications [Eze2014].  These applications mainly use the
   cooperation between vehicles to transmit messages.  The driving
   recorder is an instrument that records the video image and sound of
   the vehicle during driving.  If a traffic accident occurs in front of
   the vehicle, it can provide strong evidence for handling the traffic
   accident.  Resources can also be collected through cooperation
   between vehicles.  It can be seen that the use of vehicle-to-vehicle
   collaboration in the VANET can transmit driving recorder?s data to
   relevant departments, which is beneficial to better handling of
   traffic accidents.

   Most of the resources transmitted is used as evidence.  It is
   necessary to ensure that the data transmitted to the relevant
   transportation department are true, confidential, and not tampered,
   and traceable.  However, in the communication process, resources
   security is the main concern, including the safety protection issues
   in transmission process, the security issues of centralized storage
   in the data center, the access control and privacy protection.

   Blockchain is a distributed technology.  It uses cryptography and
   hash functions to store data in a chain to ensure that data are
   tamper-resistant and traceable.  And the technology uses a consensus
   protocol to ensure data consistency.  Therefore, blockchain
   technology can be applied to the VANET environment to solve the
   security problem and remove the dependence on trusted central
   entities.  However, the process of consensus has to solve the large
   computational problem which cannot be done on computing resources
   constrained vehicles.  As a new type of technology, Mobile Edge
   Computing (MEC) can be used not only to offload computationally
   intensive tasks from mobile devices to edge networks, but also to
   optimize processing before sending data to the core network, and to
   provide edge cloud services for mobile users at the edge.

   Therefore, this document proposes an architecture for collecting
   traffic accident information based on blockchain.  It uses blockchain
   to ensure that resources are tamper-resistant and traceable, and uses
   edge computing to solve the large computational problem of blockchain
   consensus process.





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   In section 2, some current researches on collecting transaction
   accident information are described, and their shortcomings are
   analyzed.  Section 3 proposes the structure of this document.
   Section 4 describes the working method of collecting traffic accident
   information in the framework proposed in this document.  Section 5
   discusses how the architecture guarantees the security of VANET.
   Section 6 summarizes the full document.

2.  Relate work

   With the increase of vehicles on the road, the number of traffic
   accidents has also increased.  The traditional methods of collecting
   traffic accident information are manual methods-pulling a measuring
   tape, witnessing investigation, and taking pictures on the spot,
   which takes a long time and is not conducive to the rapid evacuation
   of traffic and rapid recording of the scene.  Therefore, there are a
   large number of researchers in collecting traffic accident
   information.

   Among these studies, one type of research is to use web-based methods
   to obtain accident information.  Users upload the accident
   information to the server of the relevant transportation department
   through the browser, and the relevant transportation department
   obtains the traffic accident information from the server as the basis
   for handling the traffic accident.  Lobont et al. collect basic
   information of accidents in a web-based traffic accident collection
   system, including time and location [Lobont2013].  In a web-based
   traffic accident collection system, Williams et al. collect
   information on the severity of accidents, vehicle types, casualties,
   road conditions, weather conditions, and light conditions
   [Williams2015].  Another form of such research is the use of smart
   phones.  CrashData [Derdus2014] proposed by Derdus et al. is an
   application based on mobile smart phones.  The application can upload
   the basic information of the traffic accident to the server.  This
   type of research must be connected to the Internet and requires users
   to participate in actively uploading information, but users may not
   upload resources voluntarily.

   Another type of research is to install fixed infrastructure on both
   sides of the road to obtain traffic accident information.  In the
   traffic accident investigation and management system based on GPS
   VRS, GIS road database and stereo vision technology proposed by
   Qingwu H et al.  [Hu2011], the traffic accident information is mainly
   obtained through GPS VRS and GIS road database, and then restored
   using stereo vision technology.  In the system for collecting traffic
   accident information based on ultrasound and ZigBee wireless
   transmission technology proposed by Song H et al.  [Song2014], the
   state of the vehicle during a traffic accident is measured by



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   ultrasound, including information such as speed and direction.  This
   type of research is limited by the location of fixed infrastructure,
   and traffic accident information cannot be collected where there is
   no fixed infrastructure.

   Other research is firstly obtaining traffic accident information
   through various sensors on the vehicle, and then using the VANET to
   transmit the traffic accident information to the relevant traffic
   department.  In the literature [Abduljalil2012], Abduljalil FM et al.
   use on-board angle sensors, airbag sensors, cameras, GPS sensors,
   etc. to obtain traffic accident information, and then use Wi-Fi,
   GPRS, 3G, WIMAX, 4G-LTE wireless transmission technology to transfer
   traffic accident information to the relevant department.  In the
   VWaas service architecture proposed by Hussain R et al.
   [Hussain2013], when a traffic accident occurs, the surrounding
   vehicles use the car?s camera to capture the traffic accident
   information, and then send the captured content to the centralized
   server facility.  In this process, the vehicle directly sends traffic
   accident information to the server via 3G/4G or transmits the traffic
   accident information to the RSUs (Road Side Units) via DSRC, and then
   the RSU transmits the information to the RSUs server.

   Among the above methods for collecting traffic accident information,
   the web-based method requires users to upload traffic accident
   information to a server, which must be connected to the Internet, and
   the time for collecting information is relatively long.  Based on the
   way roadside infrastructure collects traffic accident information,
   limited by the fixed location of the infrastructure, it is impossible
   to collect traffic accident information in areas not covered by the
   infrastructure.  The method of collecting traffic accident
   information based on vehicle sensors and the VANET requires the
   participation of RSUs.  In the above three methods of collecting
   traffic accident information, only the information after the traffic
   accident can be collected, and the information before the traffic
   accident cannot be obtained.  The analysis of the accident and the
   determination of responsibility after the accident have certain
   difficulties.  And there is no guarantee that the collected traffic
   accident information is not been tampered with and can be traced to
   the source.

3.  System structure

   This document proposes a security architecture for collecting traffic
   accident information based on blockchain.  The architecture consists
   of three layers, namely perception layer, edge computing layer, and
   service layer.  The perception layer comprises vehicle and RSU,
   together forming blockchain network.  The edge computing layer
   provides computing resources and edge cloud services for the



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   perception layer.  The service layer includes cloud services and
   blockchain.

3.1.  Perception layer

   A driving recorder is installed on the vehicle, which can record the
   traffic accident information of the vehicle passing position.
   Because of the constraint of computing resource and the mobility, the
   vehicle cannot perform all blockchain functions, including wallet
   (save address and private key), miner (mining), complete blockchain
   (save all blockchain data), network routing (validate and propagate
   transaction block information, discover and maintain connections to
   peer nodes).  In this document, vehicle performs the functions of
   wallet and network routing.

   The RSU connects each other by wired communication, forming stable
   blockchain network which can ensure a unique ledger for collecting
   traffic accident information.  Therefore, all blockchain functions
   are performed on the RSU.  Even while one vehicle is moving, it can
   communicate with RSU directly or through other vehicles.

3.2.  Edge computing layer

   There are lots of transactions occurred for collecting traffic
   accident information.  If all the consensus work of the blockchain
   transaction is completed in RSU, it will inevitably affect the
   network performance and bring high delay.  Therefore, this document
   offloads the computationally intensive work to MEC, and the result is
   returned to the RSU after completion.  MEC is also responsible for
   handling other computationally intensive work, such as video or image
   processing, etc.

3.3.  Service layer

   The traffic accident information recorded by the driving recorder is
   video, which has a large amount of data and is not suitable for
   storage in blockchain of RSUs.  Because the blockchain is distributed
   storage, each blockchain node stores all the data, which consumes
   lots of storage resources.  So, the document stores the traffic
   accident information on the cloud server, which can not only store
   the data permanently, but also facilitate the inspection and evidence
   collection by the traffic police department.

   So, for data stored in the service layer, part of the data which are
   tamper-resistant and traceable, such as traffic accident data,
   traffic violation data, etc. are stored using blockchain.  The other
   part of data is stored on the cloud service.




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4.  Scheme design

   Based on the above architecture, the working method of collecting
   traffic accident information includes 4 steps, including traffic
   accident information query, traffic accident information return, RSUs
   consensus, and traffic accident information storage.  The working
   methods of collecting traffic accident information are as follows.

4.1.  Traffic accident information query

   The traffic police department initiates a traffic accident
   information inquiry request based on the time and location of the
   traffic accident.  The query request is sent to the vehicles driving
   on the road through the RSUs.  Because it is uncertain which vehicles
   have captured the traffic accident information, in order to enable
   more vehicles within the communication range of the RSU to receive
   the traffic accident information query request, the document uses the
   flooding method to send the query request.  At the same time, delay
   tolerant network technology is used to forward query requests to
   vehicles that are not within the communication range of RSU by using
   moving vehicles.

4.2.  Traffic accident information return

   The vehicle receives the traffic accident information query request
   and checks whether the traffic accident information is recorded
   locally.  If recording, extract the traffic accident information from
   the driving recorder and transmit it to the nearest RSU.  If the
   vehicle does not directly communicate with the RSUs in a single hop,
   it is forwarded through the intermediate vehicle.

   The vehicle is in a moving state.  If the traffic accident
   information recorded by the driving recorder is directly disseminated
   on the network, the probability of transmission failure will be very
   high, and the network performance will be affected.  Therefore, this
   document processes the traffic accident information in fragments, and
   then transmits the fragmented traffic accident information, and
   finally aggregates it through the RSUs.

4.2.1.  Resource fragmenting method

   The resources need to be transmitted in fragments.  However, the size
   of the fragments must ensure that a complete resource can be
   transmitted within the shortest communication time between vehicles.
   Therefore, this document determines the size of resource fragments
   according to the shortest communication time of vehicles on urban
   roads.  First, determine the shortest time for vehicle communication
   on urban roads.  The movement of vehicles on urban roads can be



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   divided into two types: same direction driving and reverse direction
   driving.  When two vehicles are driving in the same direction and in
   the reverse direction on the city road at the same speed, the
   communication time for them when driving in the reverse direction is
   shorter.

   Generally, vehicles on urban roads are not allowed to exceed the
   prescribed speed.  When the vehicle is traveling at the maximum speed
   specified on the city road, the communication time between them is
   the shortest.  Therefore, the fragment size of the resource is
   defined as the data size that can be transmitted in the shortest
   communication time between vehicles, which can ensure that any
   resource can be transmitted within the vehicle communication time
   range.

4.2.2.  Resource Naming Method

   The traffic accident information after fragmentation is named
   according to certain rules, which is convenient to distinguish from
   other vehicles and to facilitate aggregation.  The naming rules are
   as follows:

      NodeID_SerialNum_TotalNum_Time_Location

   Among them, NodeID represents the ID of the node, that is, the
   license plate number of the vehicle; SerialNum represents the serial
   number of the traffic accident information fragment; TotalNum
   represents the total number of traffic accident information
   fragments; Time represents the time when the traffic accident
   occurred; Location represents the location of the traffic accident,
   that is, the latitude and longitude.

   For the same traffic accident resource, the node ID can distinguish
   which vehicle provides the resource, and the resource sequence number
   and the total number of resource fragments can distinguish each
   fragment of the resource provided by the vehicle.  For the same car
   (same node ID), even if the resources of multiple traffic accidents
   are captured, different traffic accidents can be distinguished by the
   time and location of the traffic accident.  Moreover, each fragment
   of the same traffic accident resource can be distinguished by the
   resource sequence number and the total number of resource fragments.

4.3.  RSUs consensus

   The traffic accident information needs to be verified, agreed, and
   added to the blockchain.  The specific process is as follows:





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   a.  When RSUs receive traffic accident information, they generate a
       transaction based on the basic information and hash value of the
       traffic accident information (NodeID, SerialNum, TotalNum, Time,
       Location) and forward it to other RSUs.

   b.  Other RSUs in the blockchain network receive the transaction and
       check whether the transaction is valid and the format is correct.
       If the inspection meets the requirements, it is placed in the
       transaction storage pool and forwarded to other RSUs.  The other
       RSUs that receive the transaction repeat the process.

   c.  The RSU that obtains the right to packaging the transactions in
       the transaction storage pool into a block, and then mines the
       block.  The mining process needs to complete a large number of
       calculations, and RSUs generally do not have the ability to
       complete a large number of calculations, and the calculation
       tasks need to be offloaded to edge computing.  Edge computing
       completes the calculation task and returns the result to the
       RSUs.  The RSUs sends the block to other RSUs to spread across
       the entire network.

   d.  After receiving the block, other RSUs verify the block.  If the
       block is verified, the RSUs deletes the completed consensus
       transaction from the transaction storage pool and the block being
       mined, and at the same time adds it to the blockchain.

4.4.  Traffic accident information storage

   The RSUs aggregate the traffic accident information fragmented in the
   blockchain.  The aggregating process involves video processing, so
   this process is also offloaded to edge computing to reduce the
   workload of RSUs and increase its effectiveness.  After the edge
   computing completes the aggregation of the traffic accident
   information, it sends the complete traffic accident information to
   the RSUs.

   The blockchain in RSUs cannot store all traffic accident information.
   So it is uploaded to the cloud for storage, and the blockchain in the
   RSUs only store the digest of traffic accident information.  In order
   to ensure the security of data in cloud, the data which are tamper-
   resistant and traceable are stored using blockchain.  While, other
   data adopt the original storage method of the cloud, guaranteeing
   security by cloud computing architecture.








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5.  Discuss

   This section focuses on how the architecture guarantees the security
   for collecting traffic accident information.

   In this security architecture, vehicles and RSUs in the perception
   layer together form blockchain network to improve the security for
   collecting traffic accident information.  However, traffic accident
   information generated by the vehicle generally are stored in the
   cloud or a centralized platform so as to provide data support for
   related department.  Considering a large amount of traffic accident
   information, the perception layer does not have enough space to
   store.  Therefore, in this security architecture, the traffic
   accident information is still stored in the cloud of the service
   layer.  In order to ensure the security of data in cloud, the data
   which are tamper-resistant and traceable are stored using blockchain.
   While, other data adopt the original storage method of the cloud,
   guaranteeing security by cloud computing architecture.

   At the perception layer, the main challenge is security of traffic
   accident information during transmission.  So, blockchain in the
   perception layer is used to solve the security problem in the
   transmission process.  And the data solving the security problem in
   transmission process need to be stored in perception layer
   blockchain.  By combining MEC, the perception layer can ensure the
   security of traffic accident information in transmission process.

6.  IANA Considerations

   There are no IANA considerations related to this document.

7.  Security Considerations

   There are no Security Considerations related to this document.

8.  Conclusion

   This document proposes an architecture for collecting traffic
   accident information based on blockchain.  The architecture includes
   three layers, namely perception layer, edge computing layer and
   service layer.  The perception layer ensures the security of VANET
   data in the transmission process through the blockchain.  The edge
   computing layer provides computing resources and edge cloud services
   for the perception layer.  The service layer uses the combination of
   traditional cloud storage and blockchain to ensure the security of
   data.





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9.  Acknowledgements

   This work was supported by the Inner Mongolia Autonomous Region
   Science and Technology Achievements Transformation Project (No.
   CGZH2018124).

10.  Informative References

   [Abduljalil2012]
              Abduljalil, F., "A framework for vehicular accident
              management using wireless networks",  2012 IEEE 13th
              International Conference on Information Reuse &
              Integration (IRI), 2012.

   [Derdus2014]
              Derdus, K. and V. Ozianyi, "A mobile solution for road
              accident data collection",  Proceedings of the 2nd Pan
              African International Conference on Science, Computing and
              Telecommunications (PACT 2014), 2014.

   [Eze2014]  Eze, E., Zhang, S., and E. Liu, "Centralized Conferencing
              (XCON) Media Models",  2014 20th International Conference
              on Automation and Computing, 2014.

   [Hu2011]   Hu, Q. and H. Wang, "A Framework for Traffic Accident
              Scene Investigation with GPS VRS, Road Database and Stereo
              Vision Integration",  2011 International Workshop on
              Multi-Platform/Multi-Sensor Remote Sensing and Mapping,
              2011.

   [Hussain2013]
              Hussain, R., Abbas, A., Son, S., Kim, K., Kim, K., and O.
              Oh, "Vehicle witnesses as a service: Leveraging vehicles
              as witnesses on the road in vanet clouds",  2013 IEEE 5th
              International Conference on Cloud Computing Technology and
              Science, 2013.

   [Lobont2013]
              Lobont, L., FILICHI, A., and L. POPESCU, "Improving
              traffic safety using modern methods for accident data
              collection",  ANNALS OF THE ORADEA UNIVERSITY Fascicle of
              Management and Technological Engineering, 2013.

   [Misra2009]
              Misra, S., Zhang, I., and S. Misra, "Guide to wireless ad
              hoc networks",  Springer Science & Business Media, 2009.





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   [Song2014]
              Song, H., Ming, J., Tang, J., Zeng, D., Duan, w., and Z.
              Yin, "Wireless Positioning System for Investigation of
              Road Traffic Accidents",  Proceedings of the International
              Conference on Logistics, Engineering, Management and
              Computer Science, 2014.

   [Williams2015]
              Williams, K., Idowu, P., and E. Olonade, "Online Road
              Traffic Accident Monitoring System for
              Nigeria",  Transactions on Networks and Communications,
              2015.

Authors' Addresses

   Ru Li
   Inner Mongolia University
   Hohhot  010021
   China

   Phone: +86 15804712558
   Email: csliru@imu.edu.cn


   Xiaodong Zhang (editor)
   Inner Mongolia University
   Hohhot  010021
   China

   Phone: +86 15247168840
   Email: cszxd@imu.edu.cn


   Jun Fan
   Inner Mongolia University
   Hohhot  010021
   China

   Phone: +86 18686016307
   Email: 250832228@qq.com











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