Distributed Ledger Technology: Blockchain Compared to Directed Acyclic Graph

TL;DR

This paper compares blockchain and directed acyclic graph paradigms for distributed ledgers, analyzing their features, implementations, and scalability to inform future distributed system designs.

Contribution

It provides a comprehensive analysis of distributed ledger features and compares blockchain with DAG-based solutions using real-world examples.

Findings

DAG-based ledgers like Nano offer better scalability.

Blockchain solutions like Bitcoin and Ethereum have different consensus mechanisms.

Ledger size and transaction confirmation vary significantly between paradigms.

Abstract

Nowadays, blockchain is becoming a synonym for distributed ledger technology. However, blockchain is only one of the specializations in the field and is currently well-covered in existing literature, but mostly from a cryptographic point of view. Besides blockchain technology, a new paradigm is gaining momentum: directed acyclic graphs. The contribution presented in this paper is twofold. Firstly, the paper analyzes distributed ledger technology with an emphasis on the features relevant to distributed systems. Secondly, the paper analyses the usage of directed acyclic graph paradigm in the context of distributed ledgers, and compares it with the blockchain-based solutions. The two paradigms are compared using representative implementations: Bitcoin, Ethereum and Nano. We examine representative solutions in terms of the applied data structures for maintaining the ledger, consensus mechanisms, transaction confirmation confidence, ledger size, and scalability.