1. Introduction

In many traditional systems, information is controlled by a central authority such as a bank, hospital, or government office. While this can work, it often comes with problems like high costs, delays, security risks, or even the loss of data. Blockchain removes the need for intermediaries by allowing people and organizations to directly share verified information in real time. This not only makes processes faster and cheaper but also improves trust, since every participant can confirm the validity of transactions. In short, blockchain is a foundation for building a more transparent, secure, and efficient digital world. It answers the need for trust in a time when digital interactions are increasing every day. By combining security, transparency, and decentralization, blockchain opens the door to endless possibilities for innovation across industries.

2. Blockchain

Blockchain is a digital, decentralized ledger that stores information in blocks, which are linked together in chronological order, like a strong chain. Each block contains transactions or important data and is secured using cryptography, providing very high security. Once a block is added to the chain, it cannot be changed without everyone in the network noticing, ensuring transparency and trust. But blockchain is more than just a secure ledger; it is decentralized, meaning no single person or organization controls the entire network. Every participant (node) has a copy of the ledger, and all must agree that transactions are valid. This agreement is achieved through consensus algorithms such as Proof of Work or Proof of Stake. Additionally, blockchain can run smart contracts programs that automatically execute when certain conditions are met. For example, a payment can be released immediately when a deal is completed, or information can be unlocked automatically once documents are verified(Fang et al., 2020).

In real-world applications, blockchain is not only used in cryptocurrencies like Bitcoin and Ethereum but also in finance, healthcare, supply chains, voting systems, digital identity, and even art and music (NFTs). This makes blockchain a powerful tool for creating trust, security, transparency, and automation in the digital world.

Simple:
Imagine a shared notebook among friends where everyone records expenses and important information. Every time someone adds something, all copies are updated, and no one can delete or change anything without everyone noticing. Now imagine this notebook is connected to billions of people worldwide, all verifying transactions and information together. That’s essentially what blockchain does!

2.1 Blockchain Technology in Electronic Health Record

Blockchain technology can be used in electronic health records (EHR) to create a secure, tamper-proof, and decentralized system for storing and sharing patient data. Each patient record can be treated as a “block” containing medical information, lab results, prescriptions, and treatment history. These blocks are linked chronologically in a chain, ensuring that any modification to past records is visible to all participants. This helps prevent fraud, unauthorized access, or accidental loss of medical data. Moreover, blockchain allows patients to control who can access their health information through private keys or permissioned access systems(Sahu et al., 2024).

3.Hashgraph

Hedera Hashgraph is a decentralized data recording and transfer technology similar to blockchain, but instead of storing information in sequential blocks, it uses a directed acyclic graph (DAG). Each transaction or piece of data is recorded as a node (event) that references previous nodes. This approach allows transactions to be processed in parallel at very high speed, while data security is ensured through the “Gossip about Gossip” consensus algorithm, without requiring high energy consumption like Bitcoin mining(Verma et al., 2024).

In simple terms, Hashgraph is like a shared notebook among friends where anything someone writes can be seen by everyone, and no one can cheat. Imagine you want to share money or information with your friends; in Hashgraph, each person shares the information with a few others, who then share it with more people. This way, everyone is aware of the real situation at the same time, transactions are fast, and no one can change the past.

3.1 Gossip protocol

Gossip about Gossip” is the consensus algorithm used in Hashgraph that determines the order and validity of transactions without relying on a central authority. In this method, each node shares its transactions or events with other nodes, while also including information about which node it received the data from. This means that every node not only spreads data but also records the history of how the information propagated. Using this structure, the network can automatically determine the real order of events and reach consensus without the need for mining or high energy consumption(Gao et al., 2021).

Imagine you and your friends are in a group, and every piece of news you hear, you tell two other friends. Each person who hears the news also says, “I heard this from so-and-so.” As this cycle continues, everyone can figure out who shared the news first, who heard it later, and the true order of events. This way, everyone can be sure that no one can lie or manipulate the sequence of events.

Figure 1. Example of famous witness

In Figure 1, there are four members A, B, C, and D, C is the initiator and sends all the information it has to B, and B creates node 1 after receiving the information, which is the information of members B and It has C. In the next step, A sends a message to B, and after receiving the message, B creates a node again, now node 2 has all the information. Then B sends a message to D and D creates node 3. At this stage D has all the information and transactions and finally D sends all its information to other nodes and nodes 5 and 6 are created, all these steps are called "gossip about gossip".

3.2 Scenario on Combining Private Blockchain and Hashgraph in Electronic Health Records

This hybrid approach leverages the strengths of both Hashgraph and private blockchain, providing a robust, secure, and efficient EHR system for healthcare providers.

When patient data is collected from healthcare centers, it is pre-processed and made available to the system. Then, the data is encrypted and hashed to ensure privacy and security, and shared on the Hashgraph network as shown in Figure 2.

In this scenario, a private blockchain manages patients’ digital identities, controls access permissions, and securely stores medical data. Then, a Hashgraph is added as a fast processing layer to reduce costs and speed up transactions, without the need to mine blocks. Next, the Hashgraph acts as an intermediary network, enabling the exchange of medical data between healthcare facilities in real-time. To maintain privacy, patient data is not stored directly on the blockchain, but only its encrypted hashes are recorded. As a result, this combination creates a fast, secure, and cost-effective digital health system that, in addition to increasing interoperability, ensures data security, and offers a patient-centric model.

Figure 2. Combining private Blockchain and Hashgraph

4. Corda

Corda is an open-source distributed ledger technology (DLT) platform specifically designed for financial industries and the management of complex business processes. Developed by a consortium of financial institutions and technology companies, it aims to provide a secure, efficient, and transparent method for managing transactions and automating intricate workflows.

Corda is built on the principles of privacy, security, and interoperability and leverages smart contracts to ensure that business processes are executed accurately, consistently, and predictably. A key feature of the platform is its ability to limit data propagation to relevant parties, which enhances security and confidentiality while mitigating scalability issues in complex networks(Brown et al., 2016).

Additionally, Corda is capable of handling a high volume of transactions without compromising performance or reliability, making it highly suitable for a wide range of enterprise applications.

5. Ethereum

Ethereum is a decentralized blockchain platform that enables the execution of smart contracts and the development of decentralized applications (dApps), and it is recognized as a global infrastructure for decentralized finance (DeFi) and blockchain-based enterprise applications. The network is transparent, allowing all transactions and contract interactions to be publicly accessible, but it faces notable challenges. Its current proof-of-work (PoW) consensus mechanism requires substantial computational resources, leading to slower transaction processing, higher fees, and limited scalability, especially during periods of high network demand(Kushwaha et al., 2022).

Moreover, achieving robust privacy on Ethereum remains difficult despite methods such as zero-knowledge proofs, and interoperability with legacy systems or other blockchain networks is constrained. Integration with external systems often requires additional protocols and technologies, increasing complexity. Despite these limitations, Ethereum remains a foundational platform for innovation in the blockchain space, supporting diverse applications in finance, governance, asset tokenization, digital gaming, and the Internet of Things (IoT), and sustaining a large ecosystem of developers, projects, and an active user community.

6. Hyperledger Fabric

Hyperledger Fabric is a private blockchain platform designed to ensure data integrity among identifiable network participants. It employs a parallel processing consensus algorithm, which enhances transaction speed and allows for efficient handling of asset transfers, chaincode executions, and other data changes. Its modular architecture enables customization of consensus mechanisms, ensuring agreement among network nodes on the validity and order of transactions, maintaining a consistent state across the distributed ledger, and enforcing transaction guarantee policies. This design supports scalability and efficient resource utilization, making Hyperledger Fabric suitable for applications requiring secure, high-performance, and permissioned blockchain environments(Ucbas et al., 2023).

Hyperledger Fabric provides organizations with the flexibility to choose their preferred consensus mechanism, enabling them to optimize transaction throughput according to specific requirements. The platform supports various consensus algorithms, including practical Byzantine fault tolerance (PBFT) and Kafka-based ordering services, which deliver higher transaction rates and lower latency compared to computationally intensive mechanisms like proof-of-work (PoW).
In addition, Hyperledger Fabric allows organizations to define endorsement policies that specify the number of peer organizations required to validate a transaction. By customizing these policies, organizations can strike a balance between security and performance, optimizing the number of endorsements needed to enhance transaction throughput while preserving the integrity and reliability of the network. This combination of flexible consensus selection and configurable endorsement policies makes Hyperledger Fabric a highly adaptable and efficient platform for enterprise blockchain applications.

References

2016, BROWN, R. G., CARLYLE, J., GRIGG, I. & HEARN, M. Corda: an introduction. R3 CEV, August, 1, 14.

2020, FANG, W., CHEN, W., ZHANG, W., PEI, J., GAO, W. & WANG, G. 2020. Digital signature scheme for information non-repudiation in blockchain: a state of the art review. EURASIP Journal on Wireless Communications and Networking, , 56.

2021, GAO, N., HUO, R., WANG, S., HUANG, T. & LIU, Y. Sharding-hashgraph: A high-performance blockchain-based framework for industrial internet of things with hashgraph mechanism. IEEE Internet of Things Journal, 9, 17070-17079.

2022, KUSHWAHA, S. S., JOSHI, S., SINGH, D., KAUR, M. & LEE, H.-N.. Systematic review of security vulnerabilities in ethereum blockchain smart contract. Ieee Access, 10, 6605-6621.

2024, SAHU, D., TIWARI, N. & CHAWLA, M. Blockchain as a solution for electronic health record management: A comprehensive review. 2024 IEEE International Students' Conference on Electrical, Electronics and Computer Science (SCEECS), IEEE, 1-6.

2023,UCBAS, Y., ELEYAN, A., HAMMOUDEH, M. & ALOHALY, M. Performance and scalability analysis of ethereum and hyperledger fabric. IEEE Access, 11, 67156-67167.

2024,VERMA, P., TRIPATHI, V. & PANT, B. Secure Hashgraph for healthcare: Strengthening privacy and data security in patient records. IEEE Transactions on Consumer Electronics, 70, 1205-1213.

Comparing Blockchain Networks and Hashgraph