A Traceable Vaccine Production Supervision System with Embedded IoT Devices Based on Blockchains

Abstract

Today, vaccines play a crucial role in ensuring personal safety and are the most effective method for preventing related diseases. The ages over which vaccines are efficacious, from infancy to the old, is of utmost importance. With the recent outbreak of COVID-19 in 2019, the demand for vaccines and their usage has significantly increased. This surge in demand has led to issues such as vaccine counterfeiting and related problems, which have raised concerns among the public regarding vaccine administration. As a result, this has also resulted in a lack of trust in vaccine manufacturing companies and raised doubts about production processes. To address these concerns, this study proposed a vaccine production supervision system with Internet of Things (IoT) device based on blockchain. By utilizing IoT devices, vaccine-sensitive production data can be collected and encrypted and leaks that could lead to great benefit losses for vaccine manufacturing companies can also be prevented. This system adopts a digital signature technique to import immutable characteristics to the data, offering conclusive evidence in case any issues occur with the vaccine in the future. Finally, the system also integrates with the Inter Planetary File System (IPFS) with a blockchain solution, storing manufacturing plant vaccine production records in a secure, publicly accessible, and decentralized storage space, and also enabling public verification.

1. Introduction

Vaccines are a commonly used medical product today, not only aiding in disease prevention but also directly impacting people’s overall health. In Taiwan, every individual starts receiving vaccines from a young age. Parents mostly adopt vaccine programs to protect their children’s safety anytime and anywhere and to ensure that they remain healthy. This practice helps prevent children from contracting relatively dangerous or life-threatening diseases. Once a vaccine has been injected into a human’s body, it can be recognized as a natural infection, stimulating the body’s immune system to generate antibodies that can combat the disease. When these antibodies are produced within the immune system, the immune system gains the ability to resist the corresponding vaccine virus. This equips the body to defend itself against potential infections by the virus in the future, reducing the likelihood of more severe consequences resulting from subsequent infections.

For typical vaccine production process, as illustrated in Figure 1, vaccine manufacturing companies must submit all production records and related documents to the trusted government testing agencies. Throughout this procedure, these records are ideally primarily managed by the companies themselves [1]. In general, companies organize and compile the production data before submitting them to the government’s regulatory agency, such as the Food and Drug Administration (FDA) in the United States.

Under the traditional vaccine production management model, however, vaccine production companies have the flexibility to make arbitrary modifications to their production records, as depicted in Figure 1 with red arrows; each vaccine production record which is generated from each machine does not need to be authenticated by this enterprise company. It means that the vaccine production record may not have the corresponding digital signature and the supervisor node also cannot confirm if this vaccine production record was fake or not after the enterprise company has uploaded it to the supervisor node. On the other hand, it can cause a benefit disaster if the malicious enterprise company combines a new batch of a valid vaccine’s production history with expired materials to cheat the supervisor node. In order to address these issues, we proposed our approach to design a traceable vaccine supervision system based on blockchains, Figure 2 shows the architecture of the traceable vaccine supervision system based on the blockchain that we proposed. The proposed methodology makes the following contributions:

• Enhanced Transparency and Traceability in the Vaccine Production Process: The primary goal of this research is to develop a system that can track and record crucial data and events in real time during the vaccine production process. This will significantly enhance the transparency of the production history, providing assurance of vaccine quality and safety throughout the production process.
• Improved Security of Vaccine Production Data: By encrypting vaccine-sensitive data generated during the production process, the system also offers data protection to production facilities without compromising data security due to transparency concerns. Preserving the generated production history securely on the blockchain and the decentralized IPFS [2] ensures that data cannot be maliciously altered. In this paper, the Ethereum blockchain is adopted. The Ethereum blockchain is a secure, decentralized, and distributed ledger platform [3], and it is currently one of the most well-known and widely used open-source blockchain systems.
• Data Consistency in Vaccine Production: The proposed system also ensures consistency in vaccine production by merging and encrypting data generated during a single production cycle with timestamps. This prevents the occurrence of sensitive data swapping or modification during the vaccine production process. Additionally, under the protection of the digital signature, the vaccine enterprise company cannot deny that the modification came from other vaccine companies.
• Nonrepudiation of Production History: To establish the involvement of various production nodes and individuals in the vaccine production process, sensitive vaccine data and events generated at each production stage are accompanied by digital signatures. This ensures that in the event of vaccine-related issues, arbitrators can verify these digital signatures to confirm which parties are involved in the vaccine production process, thereby establishing a direct connection between personnel, machines, and the production history beyond data generation and storage.

Figure 2. Proposed system architecture.

Figure 2. Proposed system architecture.

2. Related Work

Blockchain originated in 2008 from a person named Satoshi Nakamoto. The concept first appeared in the white paper “Bitcoin: A Peer-to-Peer Electronic Cash System” [4], which describes Bitcoin, a decentralized electronic currency system based on blockchain technology. Blockchain is a decentralized database [5] that contains the process and information of data transactions that can be recorded and verified. It is based on a distributed network and stores data in the form of blocks. It uses cryptography to protect the security and integrity of the data. In recent years, blockchain technology has not only been applied to virtual currencies but has also found extensive applications in other fields [6], such as financial services, supply chain management [7], and smart contracts. It has also demonstrated strong potential in the emerging digital economy [8]. Therefore, under modern business and social models, blockchain is considered to have revolutionary potential. Many organizations and enterprises have begun to explore and apply blockchain technologies to improve business processes and to provide more secure, transparent, and efficient solutions.

Recently, numerous researchers have studied the application of blockchain technology in production supply chains, aiming to securely record and utilize data throughout the process of final product creation. For instance, Shao liang Peng and Xing Hu proposed a vaccine production monitoring system based on a dual-layer blockchain structure. The first layer consists of private data generated by the vaccine companies themselves stored in local databases. The second layer employs a public blockchain to store production composition data uploaded by the vaccine companies to the regulatory agency. Vaccine production data from the first layer are timestamped and digitally signed upon being uploaded to the blockchain, ensuring data correspondence between the two layers. This approach creates an immutable and transparent storage space. However, because of the centralized data storage used by these vaccine companies, forged vaccine history records might already be present before the data are uploaded.

In the context of food production supply chain management, Luisanna Cocco and Katiuscia Mannaro proposed a blockchain-based production traceability system for agricultural products [9]. This system ensures transparency and auditable traceability within specific agricultural supply chains. Internet of Things (IoT) devices are utilized to generate and record all production parameters, and the final production records are uploaded to the Inter Planetary File System (IPFS) and blockchain, simultaneously. However, this approach cannot guarantee data authenticity and nonrepudiation at the IoT device level, which may lead to uncertainties about data integrity and potential forgery or the modification of production records.

Ijazul Haq and Olivier Muselemu Esuka proposed a blockchain-based solution to combat the counterfeiting of drugs in supply chain management in the pharmaceutical industry [10]. Their goal was to increase traceability and visibility in drug supply chains, to ensure that patients receive genuine medications. Product registration records are stored on the blockchain, with text data on-chain and large files stored off-chain merged with data digests. However, the private nature of the blockchain reduces decentralization, and 51% attacks could potentially compromise data security and authenticity in their scheme. The absence of digital signatures before data uploading also raises concerns about data reliability and undeniability during future traceability efforts.

Kailash Chandra Bandhu and Ratnesh Litoriya proposed an Ethereum-based solution for healthcare supply chains [11]. Smart contracts and data immutability are leveraged to provide tracking mechanisms in the healthcare supply chain, preventing counterfeit drugs from reaching patients due to insufficient regulation and governance. Production information is uploaded to the Ethereum public blockchain, ensuring transparency and traceability. However, there is a lack of encrypted protection for production data during the manufacturing process. Although the blockchain is transparent and secure, uploaded data still could be forged or modified before uploading, and it also results counterfeit drugs potentially entering the supply chain at the same time. Additionally, certain aspects, such as product appearance codes, are not addressed, which could lead to discrepancies between on-chain records and received products in the future.

3. Proposed Scheme

In this approach, we adopt the Chen et al.’s scheme [12] as our building block to construct our system; it contains a setup phase, vaccine producing phase, and vaccine production history uploading phase. In addition, this proposed scheme adopts the PoW as the consensus mechanism and this scheme adopts the MQTT as the IoT protocol to receive the sensor’s information in the client’s app.

3.1. Setup Phase

This phase is a critical component of security in this system. Before this phase begins, each IoT device is issued a unique and distinct key pair by the certificate authority (CA). These keys are generated by the CA and they will be used for subsequent digital signatures later in the production process. After the CA has setup these keys to IoT devices, we also assumed that there exists an FDA that also issues keys for data encryption and decryption when inspecting production history data for each vaccine enterprise company. The architecture for key issuance is illustrated in Figure 3 and the symbol definition is in

Table 1. Symbol definitions.

$M_i$	Refers to the embedded system’s serial number of each IoT machine in the vaccine production line and each of the devices equipped with the emergency switch button and MQTT app which could forward the sensing data to the app, where $i\in$$\{1,\dots ,n$}.
${Mro}_i$	It represents information from all relevant operators in the IoT machine $i$.
$V{d}_i$	It represents crucial vaccine data produced by the IoT machine $i$, where $i\in \{1,\dots ,n$}.
$P{k}_i$	The public key issued by the CA to each IoT machine device, where $i\in \{1,\dots ,n\}.$
${Sig}_{{sk}_i}\left(\cdot \right)$	The digital signature function which is performed by the IoT machine $i$, when using ski to generate the digital signature and $i\in \{1,\dots ,n$}.
$P{R}_i$	The production record data transmitted from the embedded system of the IoT machine $i$ that it includes a digital signature and a vaccine production material plaintext inside, where $i\in \{1,\dots ,n$}.
$H\left(\cdot \right)$	It defines a hash operation to generate a fixed-length output of bits string.
$T_i\left(\cdot \right)$	It generates the time stamps period from current time to the end by each IoT machine $i$, where $i\in \{1,\dots ,n$}.
$\mathrm{C}\mathrm{A}$	It represents the certificate authority that issues all certificate pairs for the embedded system and FDA, etc.
FDA	It represents the Food and Drug Administration (FDA), a trustworthy government agency.
Img	Photos taken after vaccine production is completed and exterior numbering is conducted.
$E_{{pk}_F}\left(\cdot \right)$	Encrypting function by inputting the vaccine data with using FDA’s public key ${pk}_F$.

.

First, the FDA will issue a request to apply temporary certificates for each IoT device $M_i$ in each vaccine machine. In this process, as depicted in Figure 3, the CA could return these temporary certificates and FDA’s certificate to FDA. In fact, the above IoT devices are temper-proof devices of the FDA, providing the digital signatures of each vaccine’s production data while adopting temporary certificates. After each IoT device has received its certificate, it has finished this phase and enters the next vaccine producing phase.

3.2. Vaccine Producing Phase

During the vaccine production phase, as depicted in Figure 4, we employ the asymmetric encryption algorithm such as the RSA algorithm on each IoT device. These devices adopt the FDA’s public key to encrypt the production data they generate according to Equation (1). Subsequently, relevant information from each IoT device, including operator details, vaccine numbers, timestamps, encrypted production data, and the digital signature transmitted from the previous machine, undergoes hashing calculations, as shown in Equation (2). Meanwhile, the IoT device generates the relevant digital signature to ensure that the data is acquired by the next machine and that this signature is traceable throughout the vaccine production process.

This approach guarantees a seamless and interconnected production process where data integrity is maintained throughout. There is no room for data substitution, tampering, or product switching in the process; The manufacturing facility remains unaware of the private keys of any IoT device, preventing any potential forgery of production records.

In this process, ${PR}_1$ represents the digital signature and plaintext value generated by embedded device $M_1$ that includes relevant operator details, timestamps, and $M_1$’s vaccine production data encrypted by the FDA’s public key. This information is simultaneously sent from $M_1$ to both the supervisory node and the next production node $M_2$. Upon receiving the signature message ${PR}_1$, $M_2$ verifies it with the above tuples ${(Mro}_1,{PR}_1,T_1,E_{pkF}\left({Vd}_1\right))$. After the successful verification of ${PR}_1$, $M_2$ hashes ${PR}_1$, incorporates it into its own signature ${Pr}_2$, and forwards it to $M_3$. Following the same process, the data are transmitted to $M_4$. Finally, ${PR}_4$ will be incorporated with final vaccine product images $Img$, including identification images when vaccine production is completed. The entire production process algorithm is as follows:

$${PR}_1=Si{g}_{sk1}\left({Mro}_1\left|T_1\right|E_{pkF}\left({Vd}_1\right)\right)$$

(1)

$${PR}_2=Si{g}_{sk2}\left({Mro}_2\left|T_2\right|E_{pkF}\left({Vd}_2\right)|H\left({PR}_1\right)\right)$$

(2)

$${PR}_3=Si{g}_{sk3}\left({Mro}_3\left|T_3\right|E_{pkF}\left({Vd}_3\right)|H\left({PR}_2\right)\right)$$

(3)

$${PR}_4=Si{g}_{sk4}\left({Mro}_4\left|T_4\right|E_{pkF}\left({Vd}_4\right)\left|H\left({PR}_3\right)\right|Img\right)$$

(4)

In the above production data process, the vaccine production data generated by each IoT machine are encrypted using the FDA’s public key to prevent critical manufacturing methods from leaking out due to the transparency of the subsequent blockchain and IPFS storage. However, vaccine numbers, relevant each IoT machine details, timestamps, and other similar information are not encrypted but rather made public for verifying. These pieces of information, however, are protected by digital signatures, ensuring their authenticity. This setup enables individuals to verify each produced vaccine data with its corresponding signature through a trusted channel before administration and also offers the vaccine data privacy protection.

In conclusion, the final production record includes the consistency of the entire data production process and utilizes digital signatures to verify the authenticity of the machines involved. If any issues are raised with the vaccine, governmental regulatory officers can use this record to correctly link the suspected vaccine enterprise company.

3.3. Vaccine Production History Uploading Phase

The architecture of the final phase, the production history uploading process, is depicted in Figure 5. After confirmation by the supervisory node, the production history is sent to the FDA. Once the FDA completes the relevant vaccine data verification and confirms the accuracy of the received data, the history will be uploaded to the IPFS. Then, a CID number returned by the IPFS is then used to store in the Ethereum blockchain via the FDA executing a smart contract and ensuring the link relation of vaccine production between the IPFS and Ethereum.

On the other hand, the IPFS, as a decentralized storage system, links the uploaded content with its CID. If the content is maliciously altered, the CID will change it simultaneously. Therefore, the CID on the Ethereum blockchain can serve as a way to trace the source of IPFS content. Integrating these two components provides a cost-effective and highly secure storage solution and also allows for the presentation of the final production history through the IPFS as a file, such as a .pdf document or an .img image file, for verification by the public. In the meanwhile, we also implemented our approach with open-source code to simulate above IPFS and the Ethereum blockchain.

The FDA then accomplishes the uploading process through the smart contract $\mathrm{C}\mathrm{I}\mathrm{D}\mathrm{t}\mathrm{o}\mathrm{C}\mathrm{h}\mathrm{a}\mathrm{i}\mathrm{n}\mathrm{S}\mathrm{C}$, as illustrated in Figure 6. This smart contract includes information such as vaccine numbers, manufacturing facility names, production facility numbers, and CIDs, providing comprehensive product information. The contract can only be invoked by a specific Ethereum address that has been set up for this purpose. In this diagram, the authorized address is designated as the Ethereum blockchain address of the FDA. This prevents unauthorized individuals from calling the smart contract, except for those authorized by the FDA. The functions invoked in this smart contract are shown in

Table 2. Smart contract functions.

uploadData()	Upload Production Data to the Blockchain
setAllowedAddress()	Authorize a New Address the Node on the Blockchain

.

3.4. Vaccine Production Traceability Phase

This phase is the tracing stage of the final production history generated by the vaccine manufacturer. It is used to provide a post-tracing process when there are doubts about the records after the vaccine is produced and to assist the FDA in tracing and verifying the questionable records.

At this phase, all final production records stored on the IPFS can be reviewed and verified. The specific steps are as follows:

• The FDA can obtain the company name, production number, vaccine name, vaccine number, and CID number of the vaccine to be traced on the Ethereum.
• The obtained CID is then used to retrieve the corresponding final production history file on the IPFS.
• The FDA uses the public key issued by the CA to sequentially verify the ${PR}_{\mathrm{i}}$ digital signature generated by each IoT device using the following formula:

  $$Verif{y}_{p{k}_i}\left({{PR}_{\mathrm{i}},Mro}_{\mathrm{i}}\left|T_{\mathrm{i}}\right|E_{pkF}\left({Vd}_{\mathrm{i}}\right)|H\left({PR}_{\mathrm{i}-1}\right)\right)\stackrel{?}{=}True$$

  to determine if the ${PR}_{\mathrm{i}}$ is authentic.
• If a device’s signature ${PR}_{\mathrm{i}}$ fails verification, the system can continue to verify the signatures of subsequent nodes to determine whether the error occurred in the current record or the previous node. Once the signature node with the anomaly is identified, the system can use the hash value $H\left({PR}_{\mathrm{i}-1}\right)$ and timestamp $T_i$ of that or the previous node to trace the corresponding production equipment and operator to determine the source of the problem.
• The FDA verifies the consistency between the CID stored on the blockchain and the IPFS content and records the verification results in the form of a digest hash in a public audit ledger, which serves as a basis for subsequent administrative investigations and quality audits.

This phase leverages the data encryption mechanism and the immutability of the blockchain to achieve auditability and traceability of vaccine production information. When disputes arise regarding vaccine products, the system enables transparent and credible tracking and verification, ensuring the authenticity and reliability of the entire production process.

3.5. IoT Device Recovery Phase

Due to the recovery mechanism to the failure of IoT devices and loss of connectivity, each device can assume that it is equipped with a stop switch button and also adopts the UPS power station in a power-loss situation. In one hand, if the IoT device does not work because of system failure, the vaccine production operator could stop the IoT device with the stop switch button to stop the IoT device. On the other hand, the operator could trace the vaccine production process to when this error happened and it could perform the vaccine production process again when this malfunctional IoT device is replaced by a new IoT device.

4. System Implementation and Efficiency Comparisons

4.1. IPFS and Blockchain System Implementation

This section provides an overview of the entire experimental process and results carried out by the FDA upon receiving production data from manufacturers, followed by successful verification of the vaccine data signature and subsequent uploading to the IPFS and the Ethereum blockchain. Once the FDA confirms the successful qualification of the testing results, the corresponding production history is uploaded to the IPFS decentralized storage space. After storing the file, the IPFS returns a CID, as depicted in Figure 7.

Through its CID, which is also stored within the Ethereum blockchain, the document’s content can be located. Leveraging the tamper-resistant nature of blockchain technology, the production history gains a heightened, robust level of security. The content of the file can be viewed via the internet by accessing the IPFS application website and inputting the CID link.

Figure 8 shows the subsequent step in which the FDA successfully uploads the CID to the Ethereum blockchain, in which the data are successfully stored to a block. Users have the ability to examine the hash value of this block, as depicted in Figure 9. Then, by accessing this hash value, users can view its content and correspond it with the file stored in the IPFS using the CID, as illustrated in Figure 10.

The corresponding CID and relevant information of production data are then successfully stored on the blockchain. The above describes all the relevant processes of the FDA’s on-chain implementation.

4.2. Functionality Comparisons

In this section, we compare our developed solution with those proposed by [1,9,10,11]. The final results are summarized in

Table 3. Comparison of solutions.

Solution	Ours	[1]	[9]	[10]	[11]
Authenticity	✓	✓	×	×	×
Integrity	✓	×	✓	×	✓
Full Decentralization	✓	✓	×	×	×
High Transparency	✓	✓	✓	×	✓
Traceability	✓	✓		✓	✓
High Readability	✓	×	✓	✓	×
IPFS and Ethereum blockchain Implementation	✓	×	✓	×	×

✓: Satisfied, ×: not satisfied.

. We evaluate these solutions based on seven features: data authenticity, IPFS integration, full decentralization, data integrity, high transparency, traceability, and readability.

Our proposed solution outlined in this thesis involves the installation of devices by highly trusted entities. It focuses on storing and securely transmitting production data from manufacturing machines within production plants. Following the completion of the production process history, our solution integrates the IPFS and the Ethereum blockchain, resulting in an inexpensive, highly secure, non-repudiable, and highly readable storage option. This approach provides an openly transparent and trustworthy viewing space for all vaccine users. It prevents the potential manipulation of data during subsequent public data access and safeguards against data tampering by allowing users to directly access easily readable data content stored in the IPFS. Ultimately, this solution provides vaccine users with a trustworthy and no falsifiable vaccine production history for their inspection.

To demonstrate the entire system’s transmission efficiency and cost analysis, we simulated the time and computational costs consumed by each solution in invoking smart contracts and storing production data on the blockchain using Ganache, as well as the time and Gas cost for storing the final production records on the blockchain. A chart comparing efficiency and costs is presented in Figure 11. The size of the production data remained consistent and included an additional image of 5 KB for simulation purposes. A comparison based on the number of vaccine production runs and system storage time is shown in Figure 12.

5. Conclusions

This paper presents a vaccine production supervision system based on blockchain and embedded systems inspired by recent vaccine-related issues and the rise in blockchain technology. This system differs from traditional approaches where production enterprises independently record and submit production data. In this proposed approach, a trusted entity, the FDA, installs IoT devices on production machines in the manufacturing plant to collect real-time operational production data. These data are then encrypted using the RSA asymmetric encryption algorithm. The relevant operations, timestamps, and hashed data from the previous node are digitally signed and encrypted. This approach ensures that the final production record remains concise while maintaining the nonrepudiation of digital signatures.

This system offers advantages over other similar systems in pinpointing the specific production machine and related operators responsible for any vaccine-related issues that may arise in the future. Encryption of the production data alleviates concerns about the leakage of sensitive information by manufacturers. To prevent future data tampering, the data are safeguarded through the integration of the Ethereum blockchain and the IPFS, providing a dual layer of security. This approach reduces the substantial cost of storing media information on the Ethereum network. The secure and decentralized storage space not only ensures safety but also provides reliable reference information for government agencies to make informed decisions when addressing product-related issues.

The FDA, as a governmental administrative agency, establishes policies and regulations based on scientific evidence and regulatory standards for the safety, efficacy, and quality of drugs and food-related products. While this paper focuses on vaccines as the regulated products, the system’s scope is not limited to the vaccine domain. With FDA support, products in various fields, such as food, drugs, medical devices, cosmetics, and more, can benefit from this system architecture to produce comprehensive production records. This ensures a trustworthy space for consumers to verify the safety of relevant products and enables users to have solid ground for arbitration when issues arise. The proposed system architecture encompasses high security, traceability, transparency, confidentiality, data integrity, and usability to ensure effective recording of every stage in the production process from raw materials to finished products, thereby enhancing the security of each product’s manufacturing process. In the future, this paper will add the side-channel attacks on IoT devices, risks of physical compromise, processing time, resource consumption, operational costs, complete cost–benefit analysis including installation, maintenance, formal security proof and training costs for personnel in the advanced version of this proposed scheme. We will also further investigate how to integrate blockchain, the industrial Internet of Things (IIoT), big data frameworks, and the Healthcare 5.0 architecture, as demonstrated in studies by Ng et al. [13] and Wu et al. [14], to enhance real-time process monitoring and quality analysis, and to secure interoperable data management.