Distributed Ledger Techniques

Authored By

Shruti Gupta (Computer Engineering Student at VIT Mumbai)

Sarah Cheulkar (Computer Engineering Student at VIT Mumbai)

Chirantan Tondale (Computer Engineering Student at VIT Mumbai)

Samudragupta Jejurkar (Computer Engineering Student at VIT Mumbai)

Introduction to Distributed Systems

A distributed system is a set of autonomous computers that presents itself to its users as a single coherent system. The computers exchange and coordinate messages by passing them across a network. The concept is resource sharing and transparency—users access the system as if it were one system, though computation and storage are distributed over several nodes.

Some examples are cloud platforms, peer-to-peer networking, and world-scale applications such as Google Search or Netflix.

Distributed System Aims

As per Tanenbaum & Van Steen (2017), the major aims of distributed systems are:

1. Transparency – Mask the distribution complexity from users (access, location, replication transparency).

2. Scalability – Expand capacity by adding more machines.

3. Reliability & Fault Tolerance – The system must still operate even with failures.

4. Resource Sharing – Enable sharing of hardware, software, and data resources.

5. Performance – Enhance efficiency by parallelism and load balancing.

Distributed Ledger Technologies (DLTs) can be viewed as a special type of distributed systems with the capability to offer trust, immutability, and decentralization without the need for a central authority.

Distributed Ledger Technology (DLT)

A distributed ledger is a replicated database across nodes in a network. The ledger is updated through consensus protocols, keeping the integrity and consistency intact without depending on any central administrator.

Important Features:

1. Decentralization (no single point of control)

2. Consensus-based validation

3. Immutability (data cannot be easily changed once written)

4. Transparency for participants

Blockchain is the most widely used application of DLT, but not the only one. Because of its limitations (scalability, energy consumption, speed of transaction), scientists have proposed newer models of DLT other than blockchain.

“Blockchain was just the beginning. The real story of distributed ledgers is only now unfolding.”

Beyond Blockchain: Alternative DLT Architectures

1. Directed Acyclic Graphs (DAGs)

Concept: Rather than a single chain of blocks, transactions create a graph in which new transactions authenticate old ones.

Examples: IOTA, Nano

Benefits:

1. High volume of throughput

2. Near-zero transaction fees

3. Ideal for IoT and microtransactions

Use Case: Machine-to-machine (M2M) payments in IoT environments.

2. Hashgraph

Concept: Employing a gossip-about-gossip protocol, whereby nodes exchange transaction histories with each other.

Example: Hedera Hashgraph

Benefits:

1. Asynchronous Byzantine Fault Tolerant (aBFT) consensus

2. High speed and fairness of transaction ordering

Use Case: Enterprise-grade applications (supply chains, digital identities).

3. Holochain

Concept: Agent-centric design whereby each actor has their own chain, and consensus only when interactions occur.

Benefits:

1. No global consensus bottleneck

2. Lightweight and scalable

Use Case: Decentralized applications (hApps), collaborative platforms.

4. Tempo (Radix)

Concept: Logical time ordering of events based on reasoning, not global consensus.

Benefits:

1. Very high scalability

2. Improved security

Use Case: DeFi networks and large-scale financial systems.

Comparative Perspective

Though blockchain has been the best-known distributed ledger technology, other models like DAGs, Hashgraph, and Holochain present different methodologies that bypass many of the problems associated with blockchain.

Blockchain and its Proof-of-Work (PoW) or Proof-of-Stake (PoS) consensus are secure and trusted but inefficient in scalability and power usage. Bitcoin, for example, can only handle about 7 transactions per second and eats up enormous quantities of electricity.

By contrast, Directed Acyclic Graphs (DAGs), which are employed by IOTA and Nano, permit each transaction to authenticate the ones that came before it, removing the necessity for miners. This creates high scalability, minimal latency, and virtually zero transaction fees, which makes DAGs particularly well-suited for IoT networks and micropayments where efficiency is paramount.

Hashgraph, which was made mainstream by Hedera, follows a gossip-about-gossip protocol with nodes quickly gossiping transaction histories back and forth. This gives it asynchronous Byzantine Fault Tolerance (aBFT) with security, fairness of ordering, and highly high throughput. Hashgraph is therefore well-placed to serve enterprise-grade applications requiring speed and fairness, e.g., supply chain systems and digital identity management.

Conversely, Holochain departs from global consensus altogether. It's agent-centric, i.e., every participant has its own chain, and verification only happens between interactions. This renders it very lightweight and theoretically infinitely scalable, as there is no single point of bottleneck from a global ledger. That kind of architecture is more geared towards decentralized applications (dApps), peer-to-peer cooperation, and social or community-based platforms.

Hence, although blockchain performs best in cryptocurrency and DeFi use cases, DAGs perform best for IoT scenarios, Hashgraph performs at its best in enterprise settings, and Holochain drives peer-to-peer networks. Each DLT is not a substitute for blockchain but rather an optimized evolution meant to adapt to various applications.

Why Go Beyond Blockchain?

1. Scalability limits – Blockchains such as Bitcoin can handle just ~7 TPS.

2. Energy wastefulness – Proof-of-Work uses massive amounts of electricity.

3. Latency – Global consensus degrades performance.

4. Application heterogeneity – Various industries need different consensus types.

Therefore, distributed systems of the future will not be blockchain-exclusive but will use the appropriate DLT model based on the application.

Future Vision

The distributed systems of the future will most likely be hybrid environments, with several DLTs existing together:

1. DAGs for the Internet of Things and micropayments

2. Hashgraph for business-class networks

3. Holochain for low-footprint peer-to-peer applications

4. Blockchain for cryptocurrencies and DeFi

This multi-layered strategy will make distributed systems greener, more scalable, and industry-ready.

Conclusion

Distributed Ledger Technologies are a breakthrough in the evolution of distributed systems. While blockchain brought DLT into mainstream use, the emergence of DAGs, Hashgraph, Holochain, and Tempo indicates that the technology is still evolving at a very fast pace.

The future lies not in replacing blockchain, but in broadening the DLT family to meet varying requirements—enabling a more decentralized and reliable digital universe.

References

Tanenbaum, A. S., & Van Steen, M. (2017). Distributed Systems: Principles and Paradigms (3rd ed.).

Popov, S. (2018). The Tangle. IOTA Foundation.

Baird, L. (2016). The Swirlds Hashgraph Consensus Algorithm. Swirlds, Inc.

Brock, A., & Harris-Braun, E. (2018). Holochain: Reinventing Applications. Holo, Inc.

Croman, K., et al. (2016). On Scaling Decentralized Blockchains.