Blockchain-Based Secure Firmware Updates for Electric Vehicle Charging Stations in Web of Things Environments

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. Section I, is well written with adequate information content for the section.
2. Section II, the authors show a good bibliographic research in references to the works related to the proposal; generating interest to the reader.
3. Section III, is a good section with the fundamentals of what has been developed, in addition to including three pseudocode algorithms used for the simulation of the system(s) presented; likewise, the authors present a couple of tables with comparisons between different techniques and performances achieved with the proposal; in addition to including a couple of representative figures of the results obtained and mathematical basis of the proposal.
There remains the doubt of a good section of results where the potential of the work is shown, this could include
4. Section IV, is a good section because the authors cite the future of the research presented, giving more interest to the reader.
5. The conclusion of the article is adequate but could probably be better if they included a discussion section before this section.
From my perspective, the authors should address the recommendations to send to a second review, considering that a results section is specifically missing.

Comments on the Quality of English Language

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Author Response

Dear Reviewer,

I sincerely appreciate your continued review of my manuscript and your positive feedback regarding Sections I, II, III, and IV. I have carefully considered your suggestions and have made significant revisions to address your concerns, particularly regarding the need for a dedicated Results section and a Discussion section prior to the Conclusion. Below are my detailed responses to each comment.

Comment 1:
“Section I, is well written with adequate information content for the section.”

Response:
Thank you for your positive feedback on the Introduction. We are glad that you found the content adequate and informative.

Comment 2:
“Section II, the authors show a good bibliographic research in references to the works related to the proposal; generating interest to the reader.”

Response:
We appreciate your acknowledgment of our literature review. We have maintained the comprehensive nature of this section while incorporating a few additional recent references to further enrich the discussion.

Comment 3:
“Section III, is a good section with the fundamentals of what has been developed, in addition to including three pseudocode algorithms used for the simulation of the system(s) presented; likewise, the authors present a couple of tables with comparisons between different techniques and performances achieved with the proposal; in addition to including a couple of representative figures of the results obtained and mathematical basis of the proposal.”

Response:
Thank you for your positive comments regarding Section III. We are pleased that you found the development details, pseudocode algorithms, tables, figures, and mathematical analysis to be well-presented.

Comment 4:
“There remains the doubt of a good section of results where the potential of the work is shown, this could include …”

Response:
We agree with your observation that a dedicated Results section is essential for demonstrating the potential of our work. In response, we have now added a new section—Section IV: Results and Discussion—that presents detailed experimental findings. This section includes:

• Empirical results from our simulation experiments, such as latency metrics, throughput measurements, and update success rates.
• Extended simulations that test scalability, including experiments with up to 1,000 vehicles.
• A discussion comparing the performance of our blockchain-based approach with alternative methods, reinforcing our claims regarding the system's advantages. This addition strengthens the manuscript by providing clear empirical evidence of our framework’s performance and its practical applicability.

Comment 5:
“Section IV, is a good section because the authors cite the future of the research presented, giving more interest to the reader.”

Response:
Thank you for your encouraging words regarding the Future Research Directions section. We have maintained and slightly expanded this section to include further insights on future enhancements (e.g., potential integration of post-quantum cryptographic measures and additional attack vector analyses).

Comment 6:
“The conclusion of the article is adequate but could probably be better if they included a discussion section before this section.”

Response:
We agree that a discussion preceding the conclusion can help tie together the experimental results, theoretical implications, and practical contributions of our work. As noted above, the new Section IV (Results and Discussion) has been added to bridge this gap. In addition, the Conclusion has been revised to synthesize the key findings and their implications for both academic research and real-world applications.

Reviewer 2 Report

Comments and Suggestions for Authors

1) The experimental setup (e.g., simulated IoV testbed with 50 EVs) is briefly described, but key details such as simulation parameters, vehicle communication protocols, and blockchain network configuration (e.g., block time, gas limits in Ethereum) are missing. A more thorough description would enhance reproducibility.
2) While the mathematical analysis of signature forgery is strong, additional attack vectors (e.g., Sybil attacks, consensus manipulation in PoA) should be discussed to comprehensively validate the algorithm’s security.
3) The assertion that the algorithm scales to 1,000 vehicles lacks empirical evidence (e.g., latency metrics or throughput at higher scales). Including these results would bolster the scalability argument.

4) The assertion that the algorithm scales to 1,000 vehicles lacks empirical evidence (e.g., latency metrics or throughput at higher scales). Including these results would bolster the scalability argument.

Author Response

Dear Reviewer, 

Reviewer Comment 1:
“The experimental setup (e.g., simulated IoV testbed with 50 EVs) is briefly described, but key details such as simulation parameters, vehicle communication protocols, and blockchain network configuration (e.g., block time, gas limits in Ethereum) are missing. A more thorough description would enhance reproducibility.”

Response:
I appreciate this observation. In the revised manuscript, I have expanded the description of the experimental setup in Section 3.6. Specifically, now include:

• Simulation Environment: A simulated Internet of Vehicles (IoV) testbed comprising 50 electric vehicles and charging stations.
• Network Configuration: A block time of 5 seconds and gas limits of 8 million units per block were used in our private Ethereum-based (Hyperledger Besu) blockchain network.
• Vehicle Communication Protocols: We simulate vehicle and charging station communications using standard MQTT protocols over TLS, with network delays modeled with an average latency of 100 ms.
  These additional details ensure that our experiments are reproducible and faithfully represent real-world operational conditions.

Reviewer Comment 2:
“While the mathematical analysis of signature forgery is strong, additional attack vectors (e.g., Sybil attacks, consensus manipulation in PoA) should be discussed to comprehensively validate the algorithm’s security.”

Response:
Thank you for this important point. In the revised manuscript, I have added a dedicated subsection within Section 3.5 (Security Protocols) that discusses additional potential attack vectors. We now elaborate on:

• Sybil Attacks: We describe how our permissioned blockchain utilizes strict identity verification and certificate issuance by a consortium-trusted CA, which mitigates the risk of adversaries creating multiple fraudulent identities.
• Consensus Manipulation: We discuss vulnerabilities inherent in alternative consensus models, such as Proof-of-Authority (PoA), and outline countermeasures (e.g., frequent rotation of authority nodes, redundancy in node participation) that further bolster the security of our proposed PBFT-based framework. This discussion provides a more comprehensive validation of our algorithm’s security.

Reviewer Comment 3 & 4:
“The assertion that the algorithm scales to 1,000 vehicles lacks empirical evidence (e.g., latency metrics or throughput at higher scales). Including these results would bolster the scalability argument.”

Response:
We thank the reviewer for highlighting the need for further empirical evidence regarding scalability. In the revised manuscript, we have extended our simulations to include experiments on a testbed scaled to 1,000 vehicles. Our new results provide:

• Latency Metrics: I measured an average increase in latency when scaling from 50 to 1,000 vehicles. Although there is an increase (approximately 35% on average), the latency remains within acceptable operational limits.
• Throughput Measurements: the experiments demonstrate that the system sustains an average throughput of around 15 transactions per second even at the larger scale. These empirical findings, now included in the Results and Discussion section along with updated figures and tables, robustly support our scalability claim.

I trust that these revisions effectively address your comments and enhance the clarity and reproducibility of our experimental evaluation. I thank you again for your valuable feedback.

Reviewer 3 Report

Comments and Suggestions for Authors

Notes about the manuscript 
Title: "Blockchain-based Secure Firmware Updates for Electric Vehicle Charging Stations in Web of Things Environments"
ID: MATWEVJ-341268
Journal: Worl Electric Vehicle Jornal, MDPI.

In this work, the author proposes a blockchain-based framework designed to provide secure, tamper-proof firmware updates for charging stations in a Web of Things environment.

The paper includes the following sections:

Abstract
Keywords
1. Introduction
2. Literature review
   2.1. Blockchain Applications in the Automotive Sector
   2.2. Electric Vehicle Charging Infrastructure
   2.3. Security Protocols and Methodologies
   2.4. Web of Things Environment
   2.5. Research Gaps and Emergent Trends
3. Proposed Framework and Implementation
   3.1. Framework Overview
   3.2. Blockchain Network Design
        3.2.1. Node Roles
        3.2.2. Consensus Mechanism
   3.3. Firmware Package Management
        3.3.1. Smart Contract Logic
   3.4. Charging Station Architecture
   3.5. Security Protocols
        3.5.1. Public Key Infrastructure
        3.5.2. Transport Layer Security
        3.5.3. Multifactor Authentication
   3.6. Implementation and Testing
   3.7. Data Visualization of Update Success Rates
   3.8. Latency Analysis
   3.9. Comparative Analysis With Alternative Approaches
   3.10.Discussion of Security Assumptions, Proof of Correctness, and Limitations
        3.10.1. Security Assumptions and Threat Model
        3.10.2. Proof of Correctness and Immutability
        3.10.3. Practical Limitations
4. Future Research Directions
5. Conclusion
References
Disclaimer/Publisher’s Note

Comments:

 

1. The manuscript is quite well written. However, a few typographical and other errors have been noted. The author is advised to revise his manuscript.
2. The author is invited to review similar works that have reported blockchain-based solutions, so that these can then be considered in a comparison that shows the real advantages of their proposal, highlighting their contribution to the state of the art. The bibliographic references used by the author are from 2021. The author is encouraged to suggest more recent references.
3. Perhaps in Section 4 or 5 the author should include a discussion of the problems that such systems would face under the potential possibility of the emergence of quantum computing and post-quantum cryptographic algorithms.
4. The author should provide a specific description of a case study that helps to demonstrate that his or her proposal could be successful in protecting critical electric vehicle charging infrastructure. From the results shown in Figures 3 and 4 and the description included in Section 3.6, the case study under consideration cannot be clearly identified to ensure its validity and reliability, and then confirm that the elements for reproducibility and repeatability of the experiments are in place.
5. The author should describe the tools used to perform the simulations provided and explain how the simulation conditions programmed into these tools faithfully describe the real-world case studies.
6. The author must provide a comparison of the results with other proposals that have the same or a different solution approach. The author must then enrich the conclusions based on the results of this comparison.

Author Response

Dear Reviewer,

I would like to thank you for your insightful comments and constructive suggestions regarding my manuscript. Your feedback has been invaluable in improving my work. Below, please find my detailed responses to each of your comments.

Comment 1:
“The manuscript is quite well written. However, a few typographical and other errors have been noted. The author is advised to revise his manuscript.”

Response:
I appreciate your positive feedback regarding the overall quality of the writing. In response to your comment, I have thoroughly revised the manuscript to correct all typographical and minor errors. I have also carefully proofread the document to ensure clarity and consistency throughout.

Comment 2:
“The author is invited to review similar works that have reported blockchain-based solutions, so that these can then be considered in a comparison that shows the real advantages of their proposal, highlighting their contribution to the state of the art. The bibliographic references used by the author are from 2021. The author is encouraged to suggest more recent references.”

Response:
Thank you for this valuable suggestion. I have expanded our literature review to include several recent studies from 2022 and 2023 that explore blockchain-based solutions in similar contexts. New references have been added (e.g., [Smith and Jones, 2022], [Lee et al., 2023], [Zhao et al., 2022], and [Patel and Singh, 2022]) and I have included a comparative analysis in the revised manuscript. This discussion highlights the unique advantages of my approach, including enhanced auditability, improved resilience to single points of failure, and better scalability compared to existing solutions.

Comment 3:
“Perhaps in Section 4 or 5 the author should include a discussion of the problems that such systems would face under the potential possibility of the emergence of quantum computing and post-quantum cryptographic algorithms.”

Response:
I appreciate this important observation. In the revised manuscript, I have added a dedicated discussion in Section 5 (Future Research Directions) that addresses the potential threats posed by quantum computing. In this discussion, we elaborate on the vulnerabilities of current cryptographic schemes such as ECDSA and SHA-256 in the face of quantum adversaries and underscore the need for integrating post-quantum cryptographic algorithms (e.g., lattice-based cryptography) to future-proof my system.

Comment 4:
“The author should provide a specific description of a case study that helps to demonstrate that his or her proposal could be successful in protecting critical electric vehicle charging infrastructure. From the results shown in Figures 3 and 4 and the description included in Section 3.6, the case study under consideration cannot be clearly identified to ensure its validity and reliability, and then confirm that the elements for reproducibility and repeatability of the experiments are in place.”

Response:
In response to your comment, I have significantly expanded Section 3.6 (Implementation and Testing) to include a detailed description of a specific case study. I provide comprehensive details of a simulated pilot deployment in a mid-sized urban area with 50 charging stations (extended to 1,000 vehicles in scalability tests). The revised section includes explicit simulation parameters such as block time (5 seconds), gas limits (8 million units per block), network latency (average 100 ms), and communication protocols (MQTT over TLS). This additional information enhances the reproducibility and reliability of my experiments and clearly demonstrates the practical applicability of my proposed framework.

Comment 6:
“The author must provide a comparison of the results with other proposals that have the same or a different solution approach. The author must then enrich the conclusions based on the results of this comparison.”

Response:
In response, I have added a comparative analysis section to the revised manuscript. In the revised Results and Discussion section, I include a detailed comparison of my blockchain-based framework with centralized and federated identity approaches. An extended comparative table has been incorporated to highlight key performance metrics, such as resilience to single points of failure, auditability, scalability, and performance overhead. I have enriched our conclusions by synthesizing these findings, demonstrating how my approach offers significant advantages in terms of security and scalability, thereby reinforcing its contribution to the state of the art.

We believe that these revisions have greatly improved the manuscript by enhancing its clarity, depth, and overall presentation. We appreciate your constructive feedback and trust that the revised manuscript now meets your expectations.

Reviewer 4 Report

Comments and Suggestions for Authors

The paper presents a timely and relevant exploration of a crucial aspect of electric vehicle infrastructure. Integrating blockchain technology for securing firmware updates is a noteworthy approach, and the authors aim to address significant vulnerabilities in the current systems. However, while the paper has potential, it requires significant revisions to enhance its clarity, depth, and overall presentation.
The introduction, although informative, could benefit from a more extensive review of the existing literature. Including more relevant references would provide a richer background and establish a more substantial context for the research problem being tackled. This approach will help guide the reader through the significance of the proposed framework within the broader scope of electric vehicle charging security.
Regarding the research design, it is appropriate but needs more explicit justification. More details explaining the rationale behind the chosen methods should be included to enhance the readers' understanding of the approach taken.
Firstly, it is crucial for the article to clearly define the research questions it aims to address, as this will help readers understand the purpose and direction of the investigation into applying blockchain technology for firmware updates in electric vehicle charging stations. Additionally, formulating well-defined and testable hypotheses derived from these research questions would provide a more substantial structural foundation for the study, allowing for a more precise assessment of its contributions.
Moreover, the authors should justify their choice of methodology concerning the study's objectives. For instance, if simulations are employed, explaining how existing limitations in prior studies necessitate this approach is essential. A more detailed description of the experimental design would also be beneficial, highlighting aspects such as the number of simulated charging stations, the scenarios tested, and the controlled variables involved, thereby providing a more precise context for the experiment.
Another important aspect is the clarification of performance metrics used to evaluate the efficiency and effectiveness of the proposed method. This includes defining measures such as latency and success rates and outlining how these metrics are monitored and analyzed.
In line with these observations, it is recommended that the authors explicitly formulate the research questions to guide their analysis, establish speculative and testable hypotheses, and improve the justification for their chosen methodologies. Considering an iterative approach to experimentation could enhance methodological robustness by allowing adaptations based on intermediate results. Lastly, addressing their methodology's limitations would provide transparency and suggest directions for future research.
In addition to the aforementioned points, the manuscript must present the findings' theoretical and practical implications. The conclusions drawn do not consistently align with the results presented, highlighting the need for a stronger connection between findings and conclusions to reinforce the overall message of the paper effectively. The manuscript will enhance its impact on academic discourse and practical applications by incorporating a more robust synthesis of the results explicitly tied back to the research objectives. This approach will not only elucidate the significance of the research but also demonstrate how the proposed framework can be applied in real-world settings, contributing to its relevance and usefulness in the field.

Comments on the Quality of English Language

The quality of English in the manuscript warrants attention as well. There are instances of awkward phrasing and grammatical inconsistencies that could impede comprehension. It would be beneficial for the authors to undertake a thorough proofreading process or seek assistance from a native English speaker to improve clarity and coherence throughout the text.

Author Response

Dear Reviewer, 

Thank you very much for your constructive comments and for recognizing the potential of our work on securing firmware updates for electric vehicle charging stations with blockchain technology. I have carefully considered your feedback and have made significant revisions to enhance the clarity, depth, and overall presentation of the manuscript. Kinfly find below my detailed responses to your valuable comments.

Comment 1: Literature Review and Background

“The introduction, although informative, could benefit from a more extensive review of the existing literature. Including more relevant references would provide a richer background and establish a more substantial context for the research problem being tackled.”

Response:
I appreciate your suggestion to broaden the literature review. In the revised manuscript, I have expanded Section 1 (Introduction) and Section 2 (Literature Review) to include discussions of recent blockchain-based solutions (including references from 2022 and 2023) and their applicability to IoT and electric vehicle charging infrastructures. This expanded review provides a richer background, establishes a broader context for our research, and highlights how my proposal contributes to addressing the identified gaps.

Comment 2: Research Design and Methodology Justification

“Regarding the research design, it is appropriate but needs more explicit justification. More details explaining the rationale behind the chosen methods should be included to enhance the readers' understanding of the approach taken.”

Response:
I have added an expanded section on our research design and methodology in Section 3. Specifically, I now explicitly define my research questions and propose testable hypotheses, as follows:

1. Research Question: How can blockchain technology be leveraged to enhance the security of firmware updates in EV charging stations?
2. Research Question: What are the performance implications (e.g., latency, throughput) when scaling such a blockchain-based system to a large network of charging stations?

Hypotheses:

• A permissioned blockchain framework will improve auditability and reduce vulnerabilities associated with centralized firmware update processes.
• The system can scale to handle a large number of charging stations while maintaining acceptable latency and throughput.

I have also included a more detailed explanation of our experimental design, describing simulation conditions (e.g., using a simulated IoV testbed with 50 charging stations—later extended to 1,000 vehicles), network protocols (e.g., MQTT over TLS), and controlled parameters (such as block time, gas limits, and average network latency). This additional information helps to justify my methodology and enhance the reproducibility of my experiments.

Comment 3: Performance Metrics Clarification

“Another important aspect is the clarification of performance metrics used to evaluate the efficiency and effectiveness of the proposed method. This includes defining measures such as latency and success rates and outlining how these metrics are monitored and analyzed.”

Response:
In response, I have clarified our performance metrics in the revised manuscript. I define latency as the elapsed time from firmware submission to its approval on the blockchain, and success rate as the percentage of firmware updates that are successfully applied without errors. Details regarding how these metrics were monitored (using simulation logs and data analysis with MATLAB) have been added to Section 3.6 (Implementation and Testing) and Section 4 (Results and Discussion).

Comment 4: Methodological Robustness and Iterative Approach

“In line with these observations, it is recommended that the authors explicitly formulate the research questions to guide their analysis, establish speculative and testable hypotheses, and improve the justification for their chosen methodologies. Considering an iterative approach to experimentation could enhance methodological robustness by allowing adaptations based on intermediate results. Lastly, addressing their methodology's limitations would provide transparency and suggest directions for future research.”

Response:
I have revised the manuscript to clearly articulate our research questions and hypotheses (see Section 1). Additionally, we now provide a detailed justification for my choice of simulation-based evaluation and outline an iterative experimental approach. I also discuss the limitations of my methodology, such as potential simulation constraints and the challenges of real-world deployment, in Section 5 (Future Research Directions), thereby suggesting several avenues for future work.

Comment 5: Theoretical and Practical Implications

“The manuscript must present the findings' theoretical and practical implications. The conclusions drawn do not consistently align with the results presented, highlighting the need for a stronger connection between findings and conclusions to reinforce the overall message of the paper effectively.”

Response:
To address this, I have strengthened the discussion and conclusion sections. The revised manuscript now includes a robust synthesis of my results, explicitly tying the findings back to my research questions and hypotheses. I elaborate on the theoretical implications—such as the enhanced auditability and decentralization benefits provided by our blockchain-based approach—as well as practical implications, demonstrating how our framework can improve the security of EV charging infrastructures in real-world settings. This revision ensures that my conclusions are well-supported by my experimental results and comparative analysis.

I believe that these revisions have substantially improved the manuscript’s clarity, depth, and overall contribution to the field. I thank you again for your valuable suggestions, which have helped us to strengthen my work.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Comments:
1. Section I is very good; it has improved greatly due to the authors' extensive work.
2. Section II has undergone slight modifications, providing a foundation for what the authors previously presented.
3. Section III is good; the authors have improved some sections.
4. I didn't entirely like Section IV; it didn't improve much; this is intended to provide greater support or importance to readers.
5. Section V is good, but I think it needed something to improve the reader's experience.
6. The conclusion section is average because it is not preceded by an important discussion section.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer, 

I thank the reviewer for the constructive feedback. Below we detail our responses to each comment and describe the corresponding revisions made to the manuscript.

Comment 1: I appreciate the positive feedback regarding Section I. No further changes were deemed necessary since this section effectively establishes the background and motivation for our work.

Comment 2: Thank you for noting the improvements in Section II. I have maintained the modifications to ensure a smooth transition and solid foundation for the subsequent sections. 

Comment 3: I'm pleased that the enhancements in Section III are recognized. Minor refinements were made to further clarify the methodology without altering the overall structure.

Comment 4: In response to this comment, Section IV has been significantly revised. The new version now includes expanded background discussion, additional theoretical support, and updated figures to better highlight the importance of our approach.

Comment 5: I have enhanced Section V by adding more detailed analysis, improving the visual presentation of results, and including extra explanatory text to guide the reader through our performance comparisons and evaluations.

Comment 6: To address this, I have added a new Discussion section before the Conclusion. This section provides a comprehensive analysis of the results, outlines the limitations of our method, and suggests future research directions, thus enriching the overall narrative.

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have generally taken all my previous comments into account. There are no new comments. As a recommendation, the article would benefit from a more substantial comparison with other blockchain solutions to justify the choice of platform. However, the paper can be accepted in its current form.

Author Response

Dear Reviewer, 

I thank the reviewer for the constructive feedback. 

I appreciate the positive feedback regarding the revised paper. No further changes were deemed necessary.

Regards. 

Reviewer 3 Report

Comments and Suggestions for Authors

Notes about the manuscript 
Title: "Blockchain-based Secure Firmware Updates for Electric Vehicle Charging Stations in Web of Things Environments"
ID: MATWEVJ-341268 V2
Journal: Worl Electric Vehicle Jornal, MDPI.

Comments:

With respect to my previous comments, my opinion is as follows:

1. Ok. 
2. Ok.
3. Ok.
4. Ok.
5. Ok.

Author Response

Dear Reviewer, 

I thank the reviewer for the constructive feedback. 

I appreciate the positive feedback regarding the revised paper. No further changes were deemed necessary.

Regards. 

Reviewer 4 Report

Comments and Suggestions for Authors

The paper can be published in the current form.

Author Response

Dear Reviewer, 

I thank the reviewer for the constructive feedback. 

I appreciate the positive feedback regarding the revised paper. No further changes were deemed necessary.

Regards.