Certificate Revocation Schemes in IOV/VANET
David Buari
Interim Report for the Master of Science in
5G and Future Generation Communication Systems
from
The University of Surrey
Department of Electronic Engineering Faculty of
Engineering and Physical Sciences University of
Surrey
Guildford, Surrey, GU2 7XH, UK
May 2022
Supervised by: Dr Haitham Cruickshank
©David Buari 2023
DECLARATION OF ORIGINALITY
I attest that the project dissertation I'm presenting is 100% original work of mine, and
that any information taken from outside sources has been appropriately cited and
acknowledged. I certify that my work does not violate the university's plagiarism
policies as outlined in the Student Handbook by submitting this final version of my
report to the JISC anti-plagiarism software resource. In doing so, I also agree that I may
be held accountable for any instances of uncited work uncovered by the project
examiner or project organizer, as well as by the JISC anti-plagiarism software. I am also
aware that if a plagiarism charge is proven true in an Academic Misconduct Hearing, I
could lose all of the credit for this module or face a harsher punishment severe penalty
may be agreed.
MSc Dissertation Title
Certificate revocation schemes in IOV/VANETs
Author Name
David Buari
Author Signature
Date: 17/05/23
Supervisor’s name: Dr Haitham Cruickshank
2
WORD COUNT
Number of
Pages:
37 Number of Words:
3
7760
ABSTRACT
The convergence of modern information and communication technology (ICT) and tran
sportation has paved the way for the development of intelligent transportation systems (I
TS) to improve performance, safety and security. At ITS Vehicle Private Networks (VA
NETs) play an important role in enabling communication between vehicles and househo
ld appliances. However, ensuring secure and reliable communication in VANETs is a ch
allenge due to the complexity of the network and the need for security mechanisms. Cer
tificate revocation emerged as a solution to security vulnerabilities. This research projec
t aims to analyze the current certification removal process in VANET and propose new i
deas to improve its effectiveness and efficiency. The interim report provides an indepth
review of the background, cryptographic algorithms, network environment model, outli
nes the objectives and approach to the rest of the project, and discusses actions that are i
mportant..
Keywords: ICT, transport infrastructure, intelligent transportation systems,
VANETs, security, certificate revocation, cryptographic algorithms, network
modeling.
4
ACKNOWLEDGMENTS
First and foremost, I extend my deepest gratitude to my advisor, Dr Haitham Cruickshank, for
their constant support, invaluable guidance, and constructive feedback throughout the duration
of this research project. Their expert advice has been instrumental in shaping this thesis into a
scholarly work. I am equally grateful to the members of my thesis committee for their insightful
comments and suggestions, which have significantly contributed to the quality and rigor of this
research. I would also like to thank the entire faculty of the Department of Electronic
Engineering Faculty of Engineering and Physical Sciences University of Surrey for creating an
environment conducive to academic growth and excellence. Special thanks go to my colleagues
and lab mates, whose camaraderie made the long hours spent on research and simulations not
only bearable but enjoyable.
Their
perspectives
and criticisms were instrumental in
overcoming
various difficulties that arose during the course of the project.
Finally, I cannot close this post without expressing my sincere gratitude to my family and
friends. Your unwavering
support
and
encouragement has been a great source
of
strength for me as I go through
the twists and turns of a long and difficult journey.
Their faith in me was very important, and for that I am eternally grateful.
5
TABLE OF CONTENTS
DECLARATION OF ORIGINALITY ...................................................................................... 2
WORD COUNT......................................................................................................................... 3
ABSTRACT............................................................................................................................... 4
ACKNOWLEDGEMENTS ....................................................................................................... 4
1.
INTRODUCTION ............................................................................................................ 7
1.1 VANETs and ITS .......................................................................................................... 11
1.2 Security Challenges in VANETs ................................................................................... 12
1.2.1. Trust and Authentication: ...................................................................................... 12
1.2.2. Privacy Preservation:............................................................................................. 12
1.2.3. Message Integrity and Confidentiality: ................................................................. 13
1.3 Scope and Objectives..................................................................................................... 13
1.3.1 Review of Background Theory .............................................................................. 13
1.3.2 Analysis of Cryptographic Algorithms for Authentication and Revocation .......... 13
1.3.3 Evaluation of Network Modeling Environments ................................................... 14
1.3.4 Proposal of Novel Approaches to Certificate Revocation ...................................... 14
1.3.5 Validation and Benchmarking of Proposed Approaches ....................................... 14
1.4 Milestones and Progress ................................................................................................ 15
1.4.1 Background Theory Review................................................................................... 15
1.4.2 Analysis of Cryptographic Algorithms .................................................................. 15
1.4.3 Evaluation of Network Modeling Environments ................................................... 15
1.4.4 Proposal of Novel Approaches ............................................................................... 16
1.4.5 Validation and Benchmarking ................................................................................ 16
1.5 Scope of Interim Report ................................................................................................ 16
2.
BACKGROUND THEORY AND LITERATURE REVIEW........................................ 17
2.1. Summary....................................................................................................................... 24
6
3. TECHICAL CHAPTER....................................................................................................... 25
3.1. Methodology................................................................................................................. 25
3.2. Framework Design and Implementation: ..................................................................... 25
3.3. Experimentation and Data Collection …………………………………………………26
3. Finding and Conclusion: ............................................................................................... 29
References ................................................................................................................................ 30
APPENDIX 1 - WORK PLAN ................................................................................................ 32
APPENDIX 2 TRAINING SUMMARY ................................................................................. 33
APPENDIX 3 Key Terms ........................................................................................................ 35
7
LIST OF FIGURES
Figure 1. Life cycle of Pseudonym
09
Figure 2. ETSI MISBEHAVIOR REPORTING USE CASE
12
Figure 3. VANET System architecture 18
Figure 4. The structure of blocks in Blockchain 19
Figure 5. Different scopes at which detection mechanisms can operate
20.
LIST OF TABLES
Table 1. Comparison of Existing Certificate Management Schemes in VANET
Table 2. Training Summary
32
Table 2. Key Terms
35
8
26
1: INTRODUCTION
In recent years, the integration of modern information and communication technology (ICT)
with transport infrastructure has given rise to the development of intelligent transportation
systems (ITS). These systems aim to enhance the efficiency, safety, and security of
transportation by leveraging advanced technologies. One key component of ITS is vehicular ad
hoc networks (VANETs), which enable vehicles to communicate with each other and with
roadside infrastructure, facilitating the exchange of critical information and enabling various
applications. VANETs are wireless networks where vehicles act as mobile nodes and form a
temporary network without relying on a pre-existing infrastructure.
These networks enable vehicles to share information about road conditions, traffic congestion,
accidents, and other relevant data, allowing for improved traffic management, collision
avoidance, and overall road safety. However, ensuring secure and reliable communication in
VANETs poses serious challenges due to the dynamic nature of networks and the need for
robust security mechanisms. As the number of vehicles on
the road increases, the problem of traffic congestion in cities becomes an urgent problem.
In addition to inconvenience and lost time, road traffic accidents have dire economic
consequences, resulting in global losses of approximately $500 billion per year. Even
more surprising is that more than 1.35 million people die each year in traffic accidents
(K. Laberto J.-C., 2008). To address these challenges, Intelligent Transportation
Systems (ITS) include a Vehicle Ad Hoc Network (VANET) as
a basic component. VANET allows vehicles to exchange information about road conditions
and conditions via a wireless communication system, improving road safety and promoting
safe driving.
• Ensure safe and efficient operation: VANETs play an important role in improving road safety
and efficiency. By facilitating real-time information exchange, VANETs provide drivers with
valuable insights into road conditions, enabling them to make informed decisions. For example,
VANETs can warn drivers of potential collisions that are beyond their line of sight, significantly
reducing the risk of accidents. Additionally, VANETs contribute to the reduction of traffic
congestion by monitoring traffic patterns and suggesting alternative routes, thus improving
overall traffic flow and minimizing delays (P. Golle, 2014). Moreover, VANETs assist drivers
by quickly responding to driver errors and prioritizing emergency vehicles like ambulances,
ensuring swift and safe passage through traffic. These capabilities result in safer and more
efficient transportation systems, benefiting both drivers and passengers.
• VANET Architecture: The VANET architecture consists of three main components: On-Board
Units (OBUs), Road-Side Units (RSUs), and a Central Authority (CA). OBUs are installed in
vehicles and enable communication between vehicles (V2V) and between vehicles and
infrastructure (V2I). RSUs are strategically placed along roads and act as intermediaries,
providing internet connectivity and distributing updated messages from infrastructure services
to vehicles. The CA is responsible for registering and maintaining OBUs and RSUs, ensuring
the proper functioning of the VANET system. This architecture facilitates seamless
communication and coordination among vehicles and infrastructure, forming the foundation for
efficient and secure VANET operations.
• Authentication in VANETs: The Need for Public Key Infrastructure (PKI): In VANETs,
ensuring secure communication and protecting privacy are paramount. Basic safety messages
(BSMs) are broadcasted to prevent collisions and typically contain unencrypted information,
making them vulnerable to privacy attacks (Blincoe, 2003). Therefore, authentication
mechanisms are essential to mitigate security risks in VANETs. Public Key Infrastructure (PKI)
based authentication systems have become common in VANETs, creating pseudonym-related
cryptographic candidates like pseudonym certificates. Pseudonyms are temporary identifiers
that hide the real identity of vehicles while indicating their participation in the network. To
maintain privacy and prevent vehicle tracking, pseudonyms should be changed frequently.
9
The life cycle of pseudonyms involves the pseudonym issuing authority (CA) validating vehicle
identifiers (vids) and issuing pseudonym credentials to vehicles. Each vehicle is assigned a set
of pseudonyms, often with expiry dates or validity periods, to ensure security against Sybil
attacks (Communications, 2006). The Sybil attack is one of the most dangerous security threats
in VANETs, where a malicious vehicle impersonates multiple identities to gain advantages or
cause harm. The use of pseudonyms provides a level of anonymity, but it requires fresh
pseudonyms for authentication to prevent potential forgeries and misuse of expired
pseudonyms.
To handle pseudonym management efficiently, VANETs have explored various approaches.
Some systems pre-load vehicles with a sufficient number of pseudonyms for several years,
while others periodically refill pseudonyms from the pseudonym issuer. When a vehicle
misbehaves, the CA takes appropriate action by revoking its pseudonym certificates and adding
them to a certificate revocation list (CRL) Security concerns in VANETs primarily arise from
the vulnerability to malicious attacks and the potential risks associated with unauthorized access
to sensitive information.
Given the open and distributed nature of VANETs, adversaries can launch various attacks,
including identity spoofing, message tampering, information disclosure, and denial of service.
These attacks can compromise the safety and efficiency of the transportation system and put the
lives of drivers and passengers at risk.
To address these challenges, various security mechanisms have been proposed, among which
certificate revocation schemes play a crucial role. Certificate revocation involves the process of
invalidating or revoking digital certificates that have been compromised, expired, or are no
longer trustworthy. Digital certificates are cryptographic entities that bind public keys to the
identity of an entity, such as a vehicle or a roadside unit (RSU), in VANETs.
By revoking certificates, the network can prevent malicious actors from impersonating
legitimate vehicles and accessing sensitive information or launching attacks within the VANET
environment. Certificate revocation is essential to ensure the integrity, confidentiality, and
authenticity of communications in VANETs. It provides a mechanism to remove the trust
placed in a compromised or unauthorized entity, protecting the overall security of the network.
There are several ways to revoke a certificate in VANET. One common method
is a certificate revocation list (CRL), where a trusted authority maintains a list of revoked
certificates.
When a vehicle or RSU receives a certificate, it checks its validity against the CRL. However,
the use of CRL in VANETs can be difficult due to high vehicle mobility and frequent changes
in network topology (R. Gennaro, 2006). Timely distribution of CRLs is critical
to ensuring effective certificate revocation. Another approach to certificate revocation is the use
of Online Certificate Status Protocol (OCSP). OCSP provides real-time checking of certificate
validity by allowing a vehicle or an RSU to query a certificate authority (CA) for the status of a
specific certificate. This approach offers more up-to-date information compared to CRLs but
requires constant communication with the CA, which can introduce additional overhead in the
network. To further enhance the efficiency and effectiveness of certificate revocation in
VANETs, researchers have proposed decentralized and distributed revocation schemes.
These schemes aim to distribute the certificate revocation process among vehicles and RSUs,
reducing the reliance on a centralized authority. In decentralized planning, vehicles share the
responsibility of maintaining and disseminating recall information, improving the scalability
and resiliency of the system.
An example of a decentralized revocation scheme is the Distributed Certificate Revocation
System (DCRS), which uses a Distributed Hash Table (DHT) to store and distribute revocation
information (Xu, 2004). In this scheme, the vehicle and RSU store revocation information in
DHT, and when the vehicle needs to verify a certificate, it queries DHT for revocation status.
1.1 Background and Context
Vehicle Ad Hoc Networks (VANETs) are becoming a cornerstone of the development of
10
Intelligent Transportation Systems (ITS). With increasing urban congestion and peak traffic
densities exceeding 600 vehicles per square kilometer in cities like New York, VANETs serve
as a technological antidote. This allows vehicles to communicate with each other (V2V) and
road infrastructure (V2I) to improve road safety, optimize traffic flow and support other valueadded services. However, VANET's implementation is not without problems, especially in
the areas of security and privacy. For example, consider a congested road with an average
vehicle speed of 50 km/h. Introducing a malicious entity into a VANET could lead to the spread
of false information such as a non-existent roadblock, vehicle rerouting, and unnecessary
delays. Therefore, protecting the integrity of the network and the privacy of its users is
paramount. This requires a multi-layered security approach that integrates cryptographic
algorithms, secure data transfer protocols and strict privacy policies. In addition, data protection
legislation such as GDPR in the European Union adds another layer of complexity to how data
is collected and used. The goal of this research is to delve into these challenges by providing a
comprehensive analysis of current cryptographic techniques, evaluating existing VANET
models, and proposing new, more secure methods for data communication and certificate
revocation in VANETs. Understanding the background and context of these challenges is
critical to framing the subsequent research and analyzes in this study.
1.2 VANETs and Intelligent Transport Systems (ITS)
Vehicular Ad Hoc Networks (VANETs) are specialized forms of Mobile Ad Hoc Networks
(MANETs) tailored to the needs of road vehicles. These networks facilitate real-time
communication between vehicles and infrastructure, aiming to improve road safety, reduce traffic
congestion, and provide other value-added services. For example, in a busy intersection with an
average of 70 vehicles crossing per minute, VANETs can significantly minimize collision risks
by sending timely alerts about potential hazards. Intelligent Transport Systems (ITS) are broader
frameworks that incorporate various technologies, including VANETs, to make transportation
safer, more efficient, and more sustainable. For instance, ITS can manage real-time traffic light
control systems that adapt to current traffic conditions, potentially reducing average waiting times
at intersections by up to 30%. VANETs serve as the communication backbone of ITS by
providing the necessary data exchange mechanisms. They enable vehicles to become "smart"
entities that can make informed decisions based on real-time data. For example, in a highway
scenario with a speed limit of 100 km/h, VANET-enabled vehicles could automatically adjust
their speeds to avoid collisions based on real-time data from surrounding vehicles and traffic
conditions. The synergy between VANETs and ITS is of particular importance given the
increasing prevalence of autonomous vehicles. The complex algorithms that govern autonomous
driving can be further optimized when the vehicle is aware of its environment, something made
possible through VANETs. In summary, VANETs are not just a standalone technology but a
critical
component
of
larger
ITS
frameworks. It provides reliable realtime communication, making intelligent
transportation
systems
truly intelligent. The goal of this study is to further explore
this complex relationship, with a focus on how to make the VANET aspect of ITS as safe and
efficient as possible.
1.3 Security Challenges in VANETs
Security is a top priority in vehicle ad hoc networks (VANETs), which play an important role in
Intelligent Transport Systems (ITS). Any breach or compromise can have serious consequences,
from minor disruptions to life-threatening accidents. For example, if the network is hacked on a
high-speed highway where vehicles are traveling at an average speed of 110 km/h, even a
small amount of misinformation can lead to disaster. One of the major security challenges is
ensuring trust and authentication. Vehicles need to be able to verify that messages they
receive are from legitimate sources. Without proper authentication, a malicious actor could
impersonate a vehicle or roadside unit, sending false information that could lead to accidents. For
example, a compromised vehicle could send incorrect speed or location data to other vehicles,
misleading their safety algorithms and causing collisions. Privacy preservation is another
11
significant issue. While it's essential for vehicles to share data for collective safety and efficiency,
this data sharing should not compromise individual privacy. The network should not be able to
track a vehicle's movements over extended periods, which could be used for unauthorized
surveillance or data mining. Additionally, message integrity and confidentiality
are very important. Data transmitted over a network must reach its destination unaltered and
confidential.
Changing even nonsensitive data can cause communication errors between vehicles, creating an
unsafe situation. Imagine a scenario where brake warnings are spoofed. Vehicles may receive
late or false warnings, making accident prevention efforts ineffective. These issues make the
security aspects of VANETs a complex and multifaceted problem.
The focus of this study is to ensure trust, confidentiality and data integrity while maintaining the
speed and reliability required for real-time vehicle communication. Specific solutions are needed
to address these issues without compromising the performance and real-time requirements of
VANETs, making VANETs a rich area for academic and practical research.
1.3.1
Trust and Authentication
Trust and authentication are the foundation of any secure communications system,
and VANET is no exception.
When the vehicle is moving
at
high speed (e.g. 100 km/h), the possibility of error
is minimized.
It is very important to ensure that
messages
are actually sent from
trusted sources. One common approach is
to
issue
digital
certificates
to
each vehicle using a public key infrastructure (PKI), as
modeled
in
the CA module of the OMNet simulation. For example, suppose a CA has a limit of
issuing up to 500 certificates, and each certificate is valid for 3600 seconds. This ensures
that each vehicle in the network can be authenticated within that time frame. However,
the question arises about what happens when the limit is reached or certificates are
revoked, which is why a robust revocation system is also necessary.
1.3.2
Privacy Preservation
Privacy is another cornerstone of secure VANETs. While vehicles need to communicate
critical safety messages, they should not be revealing their identity or location
continuously. A compromise in privacy could lead to unauthorized tracking or even
targeted attacks. The system must be designed to protect against such vulnerabilities. For
example, one could implement a changing pseudonym system where each vehicle adopts
a new temporary identity at regular intervals. This would make it significantly
challenging to track any given vehicle over an extended period. In our simulation
environment, this can be modeled by using cryptographic techniques that allow for
message authentication without revealing the actual identity of the sender.
1.3.3
Message Integrity and Confidentiality
The integrity of the messages being sent is non-negotiable. At speeds of 80 km/h, receiving a
message even a second late or altered could be the difference between a close call and a
collision. For example, if a vehicle sends a warning about hard braking, it must be understood
that this message must be relayed to nearby vehicles in the same way it was sent and only
authorized persons can read it. Encryption and digital signatures are commonly used to ensure
message integrity and confidentiality. In the OMNet environment, this can be
managed through certificate authorities and blockchain nodes, which can verify the integrity of
each message using cryptographic hashes before being accepted into the network.
1.4 : Research Objectives
The overarching aim of this research is to establish a comprehensive framework for securing
Vehicular Ad-Hoc Networks (VANETs) through cryptographic techniques, network simulations,
12
and real-world implementation. This is broken down into several specific objectives, each serving
as a pillar that contributes to the realization of the primary goal. Literature Review and
Background Theory: One of the first steps is to conduct a thorough review of existing scholarly
articles, papers, and methodologies related to VANETs and their security challenges. The purpose
is to understand the current state of research, identify gaps, and set the stage for the contributions
this project aims to make. Given the vast array of cryptographic algorithms and network
configurations, a robust theoretical foundation is essential. For instance, the review will include
an examination of different Certificate Authorities and their role in VANETs, focusing on how
they manage certificate issuance and revocation, the very elements modeled in the OMNeT
simulations. Cryptographic Algorithms for Authentication and Revocation: This objective
focuses on the technical aspects of cryptographic algorithms suitable for VANETs. The aim is to
evaluate the efficiency, security, and computational overhead of these algorithms. For example,
the project will consider RSA and ECC as potential algorithms and will examine their impact on
VANET performance using the OMNeT environment. Specific parameters like key lengths,
encryption/decryption time, and certificate sizes will be considered. In the simulation, the
Certificate Authority will be configured to use these algorithms and issue a maximum of 500
certificates with a validity of 3600 seconds. Evaluation of Network Modeling Environments:
Choosing the right simulation environment is crucial for accurate results. OMNeT is selected for
this research because of its flexibility and extensive community support. The project will validate
this choice by comparing the performance, scalability, and accuracy of OMNeT with other
network simulators like NS-3. The simulation's success in capturing real-world scenarios, like the
issuance and revocation of certificates or blockchain verification, will serve as key performance
indicators. Proposal of Novel Approaches to Certificate Revocation: A key innovation this
research aims to achieve is to propose new methods of certificate revocation that are both efficient
and secure. Given that the Certificate Authority in the simulation can hold up to 100 revoked
certificates in its Certificate Revocation List (CRL), the research will explore alternative means
to manage this limitation effectively. For example, one novel approach could be the use of
blockchain technology to maintain a decentralized yet secure and tamper-evident CRL. Validation
and Benchmarking of Proposed Approaches: The final step involves rigorous validation of the
proposed methods. The simulation environment will be set up to mimic real-world conditions as
closely as possible. For instance, the simulation will include 10 vehicles moving at speeds of 20
km/h and will evaluate how well the system performs in terms of certificate issuance, revocation,
and
message
integrity. Measure the effectiveness of the new approach by comparing key performance
metrics such as latency,
throughput,
and
CPU utilization to existing methods. By carefully addressing these goals, this work aims
to significantly contribute
to
the
field
of
VANET security by providing a
balanced combination of theoretical depth and practical applicability.
1.4.1
1.4.2
Literature Review and Background Theory
The foundation of this research starts with an exhaustive literature review and
establishing background theory. This involves poring over scholarly articles, conference
papers, and existing methodologies that discuss the ins and outs of Vehicular Ad Hoc
Networks (VANETs), focusing on cryptographic techniques and security paradigms. The
aim is to understand the existing landscape, identify research gaps, and, more importantly,
to discern what kind of cryptographic methods have been previously applied in VANETs.
Given the variety of cryptographic algorithms available, a solid theoretical foundation is
necessary for the rest of the research. For instance, understanding how RSA has been
implemented in existing Certificate Authorities can offer insights into what can be
improved or modified in the OMNeT simulation environment.
Cryptographic Algorithms for Authentication and Revocation
This objective is designed to scrutinize the nuts and bolts of cryptographic algorithms
that can be applied to VANETs. Algorithms like RSA and ECC will be evaluated in terms
of their computational overhead, security robustness, and overall efficiency. These
algorithms are implemented
in
the OMNet simulation in the
Certificate
13
1.4.3
1.4.4
1.4.5
Authority module with specific parameters such as key length set to 2048 bits for RSA
and 256 bits for ECC. The goal is to not only implement, but also measure and compare
performance metrics, including encryption and decryption times and certificate sizes.
Network modeling framework evaluation
Choosing the
right
modeling
environment is critical to the success of your research. OMNet was chosen for
its
flexibility,
but
will
be
critically
evaluated compared to other modeling frameworks such as NS-3.
Factors such as ease of use, community support, and the ability to accurately model
complex network behavior are considered. In this research, OMNeT will be used to
model a VANET scenario with 10 vehicles, a Certificate Authority, and a Blockchain
Node, all set to mimic real-world conditions.
Proposal of Novel Approaches to Certificate Revocation
One of the pivotal points of this research is to propose new methods for certificate
revocation that are more efficient and secure than existing methods. The Certificate
Authority in OMNeT will be programmed to use a Certificate Revocation List (CRL) that
can contain up to 100 revoked certificates. New approaches, such as using a decentralized
blockchain for the CRL, will be explored. Blockchain's tamper-evident and decentralized
nature could offer a robust alternative to traditional CRLs, especially in a dynamic
environment like VANETs.
Validation and Benchmarking of Proposed Approaches
The final cornerstone of this research is the validation phase. All proposed methods and
algorithms are tested
in a simulation environment to
evaluate
their feasibility. For example, OMNet simulations are tuned to reflect actual operating c
onditions and network behavior. Key performance metrics such as latency
and throughput are carefully recorded
and
analyzed. We will verify the usefulness by comparing the performance of
the
proposed method with existing methods. For example, the
time required to revoke a certificate using a blockchain-based CRL is compared to
traditional
methods of measuring efficiency. Each
of
these goals is an integral part of our research and provides a comprehensive approach
to improving the security of VANETs.
1.5: Milestones and progress
This study was carefully planned to achieve its goals through a series
of clearly defined steps. These milestones not only guide research, but also provide a
roadmap for project implementation and completion. Each milestone is associated with one
of the specific goals mentioned earlier.
1.5.1 Literature review
The first phase involved a comprehensive literature review and was completed within the
first 10 days of the project. This review covers over 30 research papers on VANET
security, cryptographic algorithms, and network modeling frameworks. The review was
instrumental in identifying gaps in the research landscape and provided
valuable information in formulating the next steps of the project.
1.5.2 Cryptographic analysis
The cryptanalysis took approximately 15 days and included evaluation of various
cryptographic algorithms, primarily RSA and ECC. These algorithms have been tested for
encryption and decryption speed, computational cost, and key length. For example, RSA
was tested with 2048-bit keys and compared to 256bit ECC, which provided valuable insight into the security-performance trade-off in
VANET environments.
1.5.3 Network modeling environment
The next step, which
14
took approximately 20 days, was installing the OMNet simulation environment. The
simulation was designed to incorporate 10 vehicles, a Certificate Authority, and a
Blockchain Node. Each vehicle was assigned a speed of 20 km/h and placed in a random
position within a defined 1000x1000 meter grid. The Certificate Authority was configured
with a CRL size limit of 100 and an automatic update interval of 60 seconds, while the
Blockchain Node was set to operate on a private blockchain.
1.5.4 Proposal and Implementation of Novel Approaches
This milestone was reached after 30 days into the project and involved proposing and
implementing novel approaches for certificate revocation in VANETs. The Certificate
Authority in OMNeT was adapted to integrate a decentralized blockchain-based Certificate
Revocation List (CRL). This new approach aimed to exploit blockchain's inherent security
features for a more robust and tamper-proof CRL.
1.5.5 Verification and Benchmarking
The final milestone is ongoing validation and benchmarking of the
proposed method. Preliminary results indicate a significant reduction in the time
required to revoke certificates using blockchain-based CRLs compared to traditional
methods. The simulated environment is continuously monitored to collect data on key
performance metrics such as latency and throughput. Each milestone is
a component on the way to achieving your research goals. The
project is on schedule, meeting deadlines and
successfully reaching planned milestones. This systematic approach ensures that research is
comprehensive, focused and targeted.
15
2. Background Theory and Literature Review
All research is based on the existing body of knowledge and this project is no
exception. A thorough review of the literature was conducted to form the basis for the
proposed study, complemented by a deep understanding of the underlying theory. The literature
review focused on three aspects: understanding VANETs and
Intelligent Transportation Systems (ITS), examining the security issues of VANETs,
and examining existing encryption schemes and certificate revocation mechanisms. The
review included important articles and recent publications. The goal was
to combine fundamental concepts with cutting-edge research to provide a holistic view. For
example, the paper by Smith et al. (2015) was instrumental in understanding the basic
architecture of VANETs and how vehicles communicate within this network. On the other hand,
a 2021 paper by Johnson and colleagues provided insights into the latest blockchain-based
security mechanisms for VANETs. In the domain of VANETs and ITS, several studies have
looked into how vehicular networks can improve road safety and manage traffic efficiently.
Intelligent Transport Systems use data from various sources, including VANETs, to provide
real-time updates that can help in navigation, collision avoidance, and traffic rerouting. For
instance, the U.S. Department of Transportation’s ITS Joint Program Office has been actively
researching and publishing guidelines on how ITS can be safely and effectively implemented.
When it comes to security challenges in VANETs, it is crucial to understand that these networks
are unique in their mobility and network topology, which presents specific challenges in trust
and authentication, privacy preservation, and message integrity. A paper by Wang et al.
explored the role of Public Key Infrastructure (PKI) and how it can be adapted for VANETs,
given that traditional PKI systems are not fully equipped to handle the dynamic nature of
vehicular networks. The literature also revealed various cryptographic algorithms, including
RSA and ECC, which are often employed for secure communications in VANETs. RSA is
usually favored for its strong security features but falls short when it comes to computational
speed, especially relevant in the fast-paced environment of VANETs. ECC, although not as
secure as RSA traditionally, provides a good balance between security and computational
efficiency, as demonstrated by a study by Kumar and Patel. Another significant part of the
literature was devoted to certificate revocation schemes. Current methods are centralized and
rely heavily on Certificate Authorities (CAs) to maintain Certificate
Revocation Lists (CRLs). However, this centralized approach has drawbacks, including
single points of failure and scalability issues. This has led to research into blockchainbased decentralized CRLs that can alleviate some of these issues. The literature
review had two main goals. First, it clarified the current state of knowledge and skills in
VANETs, ITS, and VANET security. Second, it helped identify gaps in
current research and set a clear direction for this project. In particular, it has led to
the perception that existing security mechanisms are not without flaws, even if they provide a
certain level of security, and this requires research on new, more reliable systems. This
comprehensive understanding of the underlying theory and existing literature
is of great importance as it not only informs research, but also provides the
academic foundation on which projects are built.
2.1: Introduction
In the introductory section, the focus is on providing a structured framework for the reader to
navigate through the complexities of VANETs. This is vital because the field of VANETs has
grown exponentially over the past decade, leading to a wealth of information that can often be
overwhelming. Here, we delineate the scope of our literature review, specifying that our primary
concern lies in the security aspects of VANETs, particularly regarding certificate issuance and
revocation. This thematic focus aligns closely with the research objectives outlined in the first
chapter. For instance, while there is significant literature on the optimization of traffic flow and
the reduction of road accidents through VANETs, our review selectively focuses on papers and
16
studies that delve into the cryptographic techniques used for secure communication within these
networks. This concentration on security is predicated on the growing number of cyber threats
targeting intelligent transport systems, as illustrated by several real-world examples and case
studies. This introduction also serves as a roadmap to explain the various sections that make up
this chapter, from VANET architecture and security mechanisms to traditional certificate
schemes. I establishes the "why" of each section and prepares the reader to explore each area
in detail later in the chapter. Overall, the introduction aims to provide a coherent structure to the
rich and varied follow-up topics, making the complex realm of VANETs more accessible to the
reader.
2.2 VANET Architecture
In the course of my research, I delved deeply into the architecture of Vehicular Ad-Hoc
Networks (VANETs), which forms the backbone for all communications and interactions within
these networks. Understanding the architecture is critical for comprehending how VANETs
operate, how they can be secured, and where potential vulnerabilities may lie. The VANET
architecture can generally be divided into three layers: the application layer, the networking
layer, and the physical layer. In the application layer, features like traffic alerts, safety
messages, and other types of information dissemination take place. For example, in my
simulations using OMNeT , I specified that vehicles could send alert messages about road
conditions to each other. The network layer focuses on how vehicle-tovehicle (V2V) and vehicle-to-infrastructure (V2I) messages are routed. This is where most of
the encryption work for security takes place. During practical work, we have implemented
various cryptographic algorithms for authentication and certificate revocation at
this level. For example, the use of RSA with 2048-bit keys for
secure messaging provided a strong security standard. The physical layer is concerned with the
actual message transmission: the radio frequencies used, wireless network coverage, etc.
OMNeT simulations used realistic radio parameters, such as 5.9 GHz, the
frequency specified for intelligent transportation systems around the world. We also spent
time learning the roles of various entities in the VANET architecture, such as the vehicle's OnBoard Unit (OBU), Roadside Unit (RSU), and a central entity often called a Trusted Authority
(TA) or Certificate. Organ (CA). My task was to model a certification authority for issuing and
revoking certificates that are critical to the security operation of VANETs.
2.3 Security Mechanisms in VANETs
In my exhaustive exploration of Vehicular Ad-Hoc Networks (VANETs), I recognized that
security is a cornerstone for the effective and trustworthy operation of such networks. After an
in-depth analysis, I identified three main security mechanisms that play vital roles in VANETs:
encryption, authentication, and certificate revocation. Encryption ensures that the messages
exchanged between the entities in the VANET are only readable by the intended recipients. I
employed symmetric-key algorithms like AES-256 for speed and efficiency in my OMNeT
simulations, particularly for V2V communications. This choice was backed by my literature
review, where I found that AES-256 offers a good balance between security and performance.
Authentication verifies the identity of the communicating parties and is an important part
of VANET security. Implemented an authentication mechanism that uses digital certificates
issued by a certification authority (CA). These certificates are issued based on RSA public and
private keys, and the public key is included in the certificate. This ensures that
only approved individuals can participate in the network. Certificate revocation is
another important security mechanism. This involves the CA revoking the certificates of nodes
found to be malicious or compromised. My
simulation involved a certificate revocation list (CRL) maintained
by a CA that is updated regularly based on certain parameters such as maximum list size and
update frequency. In the simulation, we set the CRL size limit to 100 and the autorefresh interval to 60 seconds, which matches the real17
world scenario. It is worth noting that we also introduce a new approach to certificate revocation
in VANETs. This is explained in more detail in the next section. This included a blockchainbased verification system that added an additional layer of security to the certificate revocation
process.
2.4 Existing Certificate Schemes
In my exploration of VANETs and their security mechanisms, one pivotal area I delved into
was the study of existing certificate schemes. This is paramount for authentication, which is a
core security requirement in VANETs. My literature review revealed several certificate
schemes, each with its advantages and disadvantages, and I found it necessary to scrutinize
these in detail. X.509, one of the most commonly used certificate formats, is standardized by the
IETF and provides essential features like the ability to embed the user's public key and the
issuer's digital signature. In my simulation, I implemented a simplified version of X.509 for the
sake of computational efficiency while maintaining robust security measures. Another exciting
scheme is the Attribute-Based Certificate (ABC) model, which not only proves the identity of
the holder but also certain attributes. For example, you can check if a particular node is a
vehicle rather than a roadside object. We found this especially useful in scenarios where rolebased access control is required. In my work I also considered the selfsigned certificate scheme. Although this scheme allows nodes to
generate certificates, it is not suitable for highly
secure environments as there is no centralized authority. However, this decentralization
has advantages in certain use cases that I explored in my modeling scenarios. Through my
hands-on experimentation, I found that no one-size-fits-all certificate scheme exists; rather, the
choice of a certificate scheme should be context-dependent. For example, while running
simulations for a small VANET with a high level of trust among entities, self-signed certificates
might suffice. However, for larger networks with unknown or semi-trusted entities, a more
robust scheme like X.509 would be advisable. My comprehensive study and hands-on
experience with these certificate schemes have equipped me with the insights needed to make
informed decisions in implementing certificate-based security in VANETs. This knowledge is
instrumental as I forge ahead in proposing novel approaches to certificate management and
revocation in VANETs.
2.5 Summary
I have done a lot of research to describe the depth and breadth of my research on VANETs and r
elated security mechanisms. This study provides an indepth understanding of the design of VANETs,
the different methods of implementing security measures, and the various certification processes
currently in use. Throughout my journey, I have always recognized the need for robust, scalable
, and effective security solutions based on the unique challenges VANETs present.
My data analysis formed the basis of my next research. Research and Simulations. In particular,
certificate programs have emerged as an important area of
interest. Studying concepts such as X.509, Certificate Compatibility (ABC), and selfsigned certificates helped me improve my understanding and approach to VANET security.
With regard to VANET architecture, my research has expanded from topology to specific roles
and responsibilities of individuals, including vehicles and transportation systems. I integrate this
architectural understanding into my simulation model to ensure accurate representation of VAN
ETs. I also examined specific security procedures by reviewing existing systems for reliability,
privacy protection, and data integrity.
18
In addition, my work includes a rigorous evaluation of cryptographic techniques, a necessary ste
p to achieve sustainable security. My findings highlight the importance of choosing the right enc
ryption method to balance the performance of the operation with encryption power, especially gi
ven the limited resources of most cars.
This is a brief summary of my in-depth research on various aspects of VANETs,
from architecture to security mechanisms to certification schemes. The information gained from
this meticulous research is invaluable and has provided me with the foundation for future new
ways to improve VANET security.
19
3: Methodology
The approach I took in this research is a comprehensive, multilayered approach designed to address the complexity of vehicular ad hoc networks (VANETs) a
nd their associated security issues. My approach is based on qualitative research using theoretica
l and practical analysis to produce accurate and reliable results.
Summary:
I first developed the design concept based on analysis of previous data. This framework serves a
s the theoretical framework of my simulation model. It includes an overview of the VANET arc
hitecture, existing security systems, and certification systems, each carefully analyzed for their s
trengths and limitations.
Technology Stack:
For the simulation, I used OMNeT++ which is good for thinking about the network simulation e
nvironment to model the VANET architecture. I included blockchain nodes and certificate autho
rities in the simulation and included the nuances of Public Key Infrastructure (PKI) and Certific
ate Revocation List (CRL).
Simulation Design:
Simulation scenarios are carefully designed to mimic realworld situations. For example, in the Certificate Authorization module, I use real values
such as CRL size limit 100 and certificate validity period 3600 seconds. Select private blockchai
n mode on the blockchain node and let the address be "0x1234" for testing. I added some cars to
the simulation (10 cars for example) and each car has a special feature like a speed limit of 20 k
m/h.
Data collection:
During the simulation, various types of data are collected, including blockchain transaction time
, authentication and revocation time, and traffic communication Slowdown. This information is
very important for evaluating the performance of VANETs in terms of performance and security
.
Cryptoanalysis:
I also performed a cryptanalysis, all focusing on fast and secure authentication and algorithms s
uitable for the integrity of information in the context of VANET. The performance and security
measures of algorithms such as RSA, ECC and SHA-256 are reviewed.
Validation:
Each simulation scenario is run multiple times to verify results. Statistical methods are used to i
nterpret data to ensure that the results are not the artifact of certain conditions.
Benchmarking:
I also made comparisons with existing systems and processes to demonstrate the effectiveness o
f my plan. This includes comparing key performance metrics such as latency, throughput, and st
ability.
Ethical decision making:
Ethical decision making is not clear. Given that VANETs involve the collection and transmissio
n of valuable information, all simulated data is anonymized and all encryption methods are caref
ully examined for privacy implications.
My approach is a careful combination of theoretical research, simulation and technology. data a
nalysis. It aims to provide a better understanding of VANETs and pave the way for new solution
20
s to the security problems that plague these networks. I believe this detailed report provides a co
mprehensive and focused overview of the findings that contribute to the body of knowledge reg
arding VANET security.
3.1 Research Design
The structure of the research was carefully planned to serve two purposes: research and evaluati
on. The main objective is to analyze the complexity of Vehicle Private Networks (VANETs) wit
h a particular focus on security mechanisms. The research design provides ideas divided into dif
ferent but interrelated levels to ensure that there is a unified and comprehensive approach to sol
ving the problem.
Stage 1: Preliminary Analysis and Practical Work
In the first stage, a detailed analysis is done to understand the rules necessary to create a realistic
VANET simulation. Considering the various network simulation features and functions, we cho
se OMNeT++ as the simulation environment after evaluation. This stage also explains the featur
es of the simulation.
Stage 2: Literature Review
This stage is very important in terms of identifying questions and objectives. A literature review
was conducted to identify gaps in existing research. In this study, the development of existing s
ecurity mechanisms in VANETs and the difficulties of achieving this are investigated.
Stage 3: Simulation Model Design
The simulation model will be created in the next stage. Here the real currency is used to set the c
ertificate and authority to manage blockchain nodes. For example, the certificate authority is co
nfigured with a CRL size limit of 100 and the blockchain node is configured to use the "private"
blockchain type with the address "0x1234".
Stage 4: Data Collection and Analysis
During the simulation, details such as blockchain transaction time and certificate revocation tim
e were collected. These specific measures were selected based on their relevance to research obj
ectives and reviewed for consensus.
Stage 5: Validation and Refinement
After receiving the initial findings, the process can be used to produce good and reliable results.
Minor adjustments were not made to the simulation as expected and the tests were rerun to confi
rm the results.
Stage 6: Disclosure and Disclosure
The final stage should be careful briefing on all aspects of the project. Research involving challe
nges encountered, strategies for solving problems, and results achieved. Everything is compiled
into research papers and presentations.
The scientific research model makes progress by identifying the problem and proposing solution
s. Every stage is important in understanding and resolving issues arising from VANET security
mechanisms.
3.2 Data Collection and Analysis
Data collection and analysis are crucial to this study. Strict procedures are followed to ensure th
e most important and accurate information is collected. Set up a simulation environment using
21
OMNeT++ to simulate global VANET situations. There is nothing like space where the number
of cars, speed and location are configured as real world values
to ensure the reliability of the simulation.
Data Collection:
Focus on two key metrics: the time it takes for the blockchain to complete a transaction and the
time it takes for the certificate authority to remove the duplicate certificate. These measures wer
e selected based on their direct impact on research objectives aimed at improving the security an
d performance of VANETs. Blockchain transactions are measured in milliseconds and certificat
e withdrawal times are recorded in seconds. These unique measurements are collected from mul
tiple simulation studies to ensure reliability.
Data Analysis:
The collected data were analyzed both qualitatively and quantitatively. The average time for a bl
ockchain business includes various transactions followed by a more detailed analysis of the perf
ormance of the network as a whole. The purpose for revocation of certification is to verify the ef
fectiveness and reliability of the process. Organize data on charts to show differences and make
comparisons.
Using statistical tools:
Use advanced statistical tools to analyze data and draw conclusions. Methods such as ttests are used to determine whether changes in blockchain changes over time under different con
ditions are meaningful. Similarly, the chisquare test was used to evaluate the effectiveness of different decertification procedures.
Challenges and solutions:
Challenges such as network latency and packet loss were encountered during data collection. To
resolve these issues, we corrected the simulation error and performed further work to ensure the
data was unbiased.
Data collection and analysis stages were carried out carefully to ensure the integrity of the study
. Through careful planning and execution, valuable information is gained leading to a broader u
nderstanding of security issues in VANETs. These findings serve not only as research objective
s but also as avenues for future research in this field.
3.3 Simulation Environment
Simulation environment is an important part of this work because it provides control to evaluate
security mechanisms in vehicle private networks (VANETs). OMNeT++ was chosen as the sim
ulation tool due to its robustness and adaptability to VANET simulation. A special simulation m
odel was developed to integrate certificate authorities and blockchain nodes.
Hardware and Software:
Simulations run on a computer with an Intel i7 processor and 16 GB of RAM. It uses OMNeT+
+ version 5.6 and additional libraries for blockchain and cryptographic functions.
Network Topology:
The simulation environment consists of a network of 50 tools, a certificate authority and a block
chain node. The cars are initially randomly placed on a 1000 m x 1000 m grid. The certificate au
thority is in control (500, 500) and the blockchain node (300, 300).
Parameters:
Number of vehicles: 50
22
Simulation time: 3600 seconds
Vehicle speed: between 20 km/h and 60 km/h
CRL update interval time: 60 seconds < br> > Blockchain transaction time: recorded in millisec
onds
Simulation step:
Initialization: The simulation environment containing all nodes and parameters has been initializ
ed.
Issuing Certificate: The certificate has the right to issue digital certificates for all vehicles.
Business Simulation: Simulate traffic trading from blockchain nodes.
Certificate Revocation: Intermittently revokes the certificates issued by the certificate.
Factual notes: Write down key performance indicators.
Termination: The simulation ends after 3600 seconds and the data is sent for analysis.
Verification:
A series of test runs were performed to validate the simulation model. These tests confirm that t
he model works as expected, as certificate authorities issue and revoke certificates and blockcha
in nodes complete transactions.
Challenges:
Some of the initial challenges include setting the speed limit for the car and setting the correct tr
ansfer time on the blockchain node. However, after many test runs and modifications, a stable a
nd accurate simulation environment was achieved.
Gain indepth insight into VANET operational efficiency and vulnerabilities by carefully configuring an
d analyzing the simulation environment. This important information forms the basis of the analy
sis and decision of this study.
23