Why Tagion uses Hashgraph

3 min readAug 18


We recently had the privilege of sitting down with Theis Simonsen, co-founder of Tagion, to delve into the narrative behind Tagion’s evolution. In this article, we invite you to explore the intriguing origins of Tagion and gain insights into the rationale behind adopting Hashgraph technology — a choice that sets Tagion apart in the world of blockchain and distributed systems.

The Birth of a Vision

Tagion’s inception was sparked by an encounter between Carsten B. Rasmussen, a pioneer in payment systems, and Theis Simonsen, an academic exploring innovation and economic governance. Both found themselves navigating the aftermath of the financial crisis, and a casual conversation at a summer gathering laid the foundation for a revolutionary idea.

Inspired by the possibilities presented by cryptocurrencies like Bitcoin and intrigued by the limitations of traditional financial systems, Tagion’s founders set out on a shared mission. With the addition of Kristian B. Vestergaard, a digital product innovator from GN Audio A/S, the trio embarked on a journey to forge an independent and equitable network infrastructure, with inclusivity at its core.

Navigating Challenges

Yet, every trailblazing journey is marked by challenges, and Tagion’s path was no exception. Initial concepts leaned toward a conventional blockchain system. However, concerns regarding scalability, governance, and community integration soon emerged. The turning point came when Carsten introduced an innovative application of Hashgraph — Leemon Baird’s solution to the Byzantine Generals’ Problem with a unique Node Swapping mechanism — a mechanism no one else has.

The Byzantine Generals’ Problem

Picture a group of military commanders orchestrating an attack on a fortress, communicating only through messengers. Amidst this, some commanders may betray the cause by issuing misleading orders. This scenario encapsulates the Byzantine Generals’ Problem — a problem to solve in designing a communication strategy for consensus among loyal leaders despite the presence of deceptive counterparts. This concept has parallels in securing computer systems.

Hashgraph’s Take on Byzantine Generals’ Problem

At the time of Tagion’ inception, both Bitcoin and Ethereum blockchains were using Proof of Work consensus mechanism. In PoW, miners solve intricate puzzles to validate transactions and add them to the blockchain. Yet, PoW has limitations, from energy inefficiency to scalability concerns. It also potentially paves the way for centralisation, a contradiction to the decentralised ethos that underpins blockchain technology.

Enter Hashgraph: An Innovative Solution

Hashgraph, as embraced by Tagion, addresses these drawbacks by introducing Virtual Voting — a form of asynchronous Byzantine Fault Tolerance (aBFT) algorithm. In this system:

  1. Gossip Protocol connects nodes through information sharing.
  2. Timestamps and Ordering establish a chronological event sequence.
  3. Finality emerges as a supermajority consensus, confirming agreed-upon transactions.

Through Hashgraph, Tagion attains decentralised consensus, enabling honest nodes to synchronise even in the face of potentially malicious participants.

Decentralisation Amplified

Tagion implements a unique Node Swapping mechanism to enable decentralisation, as well as reliable consensus. This system randomly rotates nodes, determined by their reputational scores and operational efficacy. By reducing susceptibility to Sybil attacks, this approach preserves the system’s integrity. Becoming a node involves a process wherein new operators must accumulate sufficient scores before joining.

Leveraging the strengths of Hashgraph and Tagion’s innovative concepts, a future characterised by inclusivity, heightened security, and operational efficiency emerges as a compelling prospect.

Next time, we’ll delve into Tagion’s innovative DART Distributed Database. Stay tuned!

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