What are nodes in blockchain?

According to a study published in Forbes, “The name blockchain is hardly accidental: The digital ledger is often described as a “chain” that’s made up of individual “blocks” of data. As fresh data is periodically added to the network, a new “block” is created and attached to the “chain.” This involves all nodes updating their version of the blockchain ledger to be identical…A majority of nodes must verify and confirm the legitimacy of the new data before a new block can be added to the ledger.”

Nodes are the backbone of the decentralized networks that make up blockchain. It acts as connection points that store, verify, and transmit data across the system. Where a single authority controls data, blockchain nodes distribute the responsibility across a peer-to-peer network. Each node maintains a copy of the blockchain ledger, either entirely (as in full nodes) or partially (as in light nodes), and validates transactions according to the network's consensus mechanism. 

How do nodes communicate in the network? 

According to a study on computer communication networks ‘Network Coding for Efficient Communication in Extreme Networks’, “A node forwards a packet with a fixed probability p. If the packet is forwarded, the neighbors that are reached do the same, unless they already sent out the packet…This principle of rebroadcasting a given message with a certain probability has been called epidemic routing, probabilistic routing, or gossiping.” Here is a more detailed breakdown of how it works: 

1. Nodes communicate in a blockchain network through peer-to-peer communication protocols that allow them to exchange data directly with one another.
2. Each blockchain has its specific protocol that ensures all nodes maintain synchronization and store the same block data.
3. One common method of communication is the gossip protocol, where a node shares new transactions or blocks with a few other nodes, propagating the information further until all nodes are updated.
4. Nodes also utilize interoperability protocols to connect and communicate with different blockchains.
5. Some blockchains employ Kademlia, a distributed hash table protocol, to efficiently locate and communicate with other nodes in the network.
6. Communication between nodes is often secured using encryption protocols like Transport Layer Security (TLS), which ensures that data remains confidential and tamper-proof during transmission.
   
   

The types of nodes 

1. Full nodes: These nodes maintain a complete copy of the blockchain ledger and validate all transactions independently.
2. Light nodes (SPV nodes): These nodes store only a portion of the blockchain, relying on full nodes for transaction validation and information retrieval.
3. Mining nodes: Responsible for validating transactions and creating new blocks by solving complex mathematical problems.
4. Master nodes: A type of full node that performs specific functions such as transaction validation but does not create new blocks.
5. Authority nodes: Approved nodes in a network that operate under a vetting process, often used in blockchains with a proof-of-authority consensus mechanism.
6. Archive nodes: These nodes store the full history of the blockchain, including all past states and transactions, for reference and analysis.
7. Validator nodes: In proof-of-stake systems, these nodes are responsible for validating new blocks and maintaining network security.
   
   

The application of nodes 

The study ‘Automatic Node Selection for High Performance Applications on Networks’ provides the collaborative role of nodes, “The minimum of the fractional cpu capacities (CPU) available to the nodes in the set... [determines] the (fractional) computation and communication capacities.”

Blockchain technology offers a solution by creating a secure, decentralized infrastructure where authorized providers can access comprehensive patient histories. Each node in the blockchain network maintains a copy of the shared ledger. Applying this to healthcare means that every medical event, from doctor visits to lab results, can be recorded as a transaction on the blockchain, creating an audit trail. Its practical application goes beyond data storage. 

Smart contracts, executed by nodes, can automate access controls and maintain compliance with regulations like HIPAA, giving patients greater control over who accesses their medical records. Blockchain can streamline claims processing and payment systems, reducing administrative overhead and accelerating reimbursements. For example, shared smart contracts among manufacturers, distributors, and healthcare organizations can reduce payment disputes and improve supply chain management.

The risk that could arise

Nodes, which are individual devices or systems that participate in verifying, validating, and storing blockchain data, are fundamental to the decentralized nature of blockchain but also represent critical points of vulnerability and operational complexity in healthcare applications. These risks can be broadly categorized into technological, organizational, and societal domains, each impacting the reliability, security, and compliance of blockchain deployments involving healthcare data.

Technological risks are among the most prominently discussed concerns regarding nodes in healthcare blockchains. Nodes contribute to the network’s scalability problem. Healthcare data streams, especially with the integration of wearable devices and IoT sensors, generate exponentially growing datasets that nodes must process, store, and validate. This causes strain on blockchain networks because each participating node often maintains a full or partial copy of the blockchain ledger and must execute consensus algorithms. 

Security risks associated with nodes are substantial and multifaceted. Since nodes collectively govern the blockchain, malicious actors targeting them can jeopardize the whole network. Another Perspectives in Health Information Management study on the revolution of blockchain noted that private permissioned blockchains, common in healthcare due to privacy requirements, are susceptible to 51% attacks, where a coalition controlling a majority of nodes could manipulate transaction validation, reverse confirmed operations, or censor data entries, leading to potential clinical and financial disasters. Given healthcare data’s sensitive nature, breaches at the node level pose risks of exposing personal health information, threatening patient privacy, and violating regulatory compliance like HIPAA.

Nodes also raise organizational risks due to the complexity and costs of deployment and management within healthcare settings. Many healthcare institutions face difficulties integrating blockchain nodes with legacy electronic health record systems, which were not originally designed to interact with decentralized ledgers. A further operational challenges was identified in the sudy noting, “lockchain is vulnerable to cyber-attacks in which the attackers can seize control of the network. If the attackers disrupt or even reverse transactions that have been validated inside the network, a disaster may result. Additionally, this evaluation identified high energy use as a hazard since it pertains to the usage of public blockchains”

Related: HIPAA Compliant Email: The Definitive Guide

FAQs

What are consensus mechanisms, and how do they relate to nodes? 

Consensus mechanisms are protocols that enable all nodes in a blockchain network to agree on the validity of transactions and the state of the blockchain. Nodes participate in this process by validating transactions and reaching a majority agreement before new data is accepted into the blockchain. 

How many nodes are needed to function effectively? 

While technically, only one node can operate a blockchain, having at least two or more nodes is recommended for effective functioning.

What are the requirements for running a blockchain node?

To run a blockchain node, you generally need:

• Sufficient bandwidth to handle network traffic.
• Adequate storage capacity to maintain a copy of the blockchain (especially for full nodes).
• Computational power to process transactions and validate blocks.
• Stable internet connection to stay synchronized with other nodes in the network.
  
  

How does blockchain improve healthcare data management?

Blockchain provides secure, tamper-proof records of health data, enabling interoperable data exchange among healthcare providers while giving patients control over their information through smart contracts and decentralized identity mechanisms.

What are smart contracts in blockchain?

Smart contracts are self-executing programs on the blockchain that automate the enforcement of agreements, such as patient consent management and access control for medical records, reducing manual intervention and increasing transparency.