Consensus algorithm, asynchronous fault tolerance, directed acyclic graph, distributed ledger — this article explores what connects these concepts and how to avoid a mental overload while understanding Hedera Hashgraph.
Presented by Swirlds Inc.
The Hedera Hashgraph Distributed Ledger Platform.
Starring:
Leemon Baird, mathematician, creator of the Hashgraph algorithm, co-founder, CTO, and chief scientist of Swirlds Inc.;
Mance Harmon, mathematician, co-founder and CEO of Swirlds Inc.;
Tom Troubridge, President of Hedera Hashgraph, Hashgraph technology evangelist.
The project includes:
Financial holding Nomura Holding;
Telecom company Deutsche Telekom;
International law firm DLA Piper;
Brazilian retailer Magazine Luiza;
Swiss corporation Swisscom AG.
I still don't understand why all information about Hedera Hashgraph is presented so confusingly; whether it's a deliberate strategy by developers or just happened by chance. In any case, writing a coherent piece about Hedera Hashgraph turned out to be quite challenging. Every time it seemed like I'd finally understood everything, it soon became clear that this was a deep misconception. Eventually, something meaningful was produced, but still — read carefully, the risk of mental strain is still present.
Part 1. The Byzantine Generals Problem and Gossip
At the core of this story is the so-called 'Byzantine Generals Problem' (Byzantine Fault Tolerance, BFT) — a thought experiment designed to illustrate the challenge of synchronizing the states of systems when communications are assumed to be reliable but nodes are not. Interested parties can delve deeper into the topic here or here.
The algorithms of the Hedera Hashgraph platform are developed based on a specific case of Byzantine Fault Tolerance — the asynchronous Byzantine Generals Problem, or aBFT. In 2016, mathematician Leemon Baird first proposed a solution for it and, being smart, promptly patented it.
The Hedera Hashgraph platform is characterized by the collaborative use and synchronization of digital data according to a consensus algorithm, physical decentralization of data storage nodes, and the absence of a single control center. However, the Hashgraph protocol (in this case, Hedera is the ecosystem, Hashgraph is the protocol) is not classified as a blockchain but rather an acyclic graph, consisting of parallel sequences that begin at one node and reach the end node through various paths.
Roughly speaking, while a traditional blockchain can be visually represented as a strict sequence of links (which is, in fact, its main property), Hashgraph resembles a bonsai with numerous branches. Since the number of simultaneous cycles is virtually unlimited, Hashgraph allows for a vast number of transactions to occur simultaneously (developers claim up to 250,000 per second, which exceeds even Visa's capabilities by five times, not to mention the Bitcoin network), and transaction fees are generally non-existent.
Another fundamental difference between Hashgraph and traditional blockchain is the gossip subprotocol. Within the distributed ledger, each transaction does not entail transmitting all data, but rather information about the information (Gossip about Gossip). A node informs two other arbitrary nodes about the transaction, each of which then broadcasts messages to two others until the number of informed nodes is sufficient to reach consensus, which occurs when a majority of nodes have been notified (and this is how the claimed number of transactions per unit of time is achieved).
Part 2. Blockchain Killer or Not
Currently, Hedera Hashgraph is in the development process. In particular, testing of its own cryptocurrency supporting micropayments, a distributed network file storage system, and scenarios for creating smart contracts based on Ethereum environment languages is underway.
Opinions about this project are remarkably polarized. Some sources bluntly refer to Hashgraph as the "blockchain killer," while others rightly point out that there are no examples of functioning decentralized applications in the Hedera environment. Additionally, some are concerned that the foundation of the platform is patented, and its development is under the control of a board that includes representatives from several Fortune 500 companies (though this last point suggests that the project has substantial potential and is certainly not a scam). By the way, some time ago the project was spun off into a separate company, Hedera Hashgraph, which also indicates its priority for developers.
The developers quietly raised $18 million for operational needs during a private token sale and later an additional $100 million. There are no specifics regarding the ICO, and overall, the Hedera Hashgraph roadmap is notably vague, which does not prevent the company from actively promoting this consensus algorithm. The company is working vigorously to form various professional communities—from programmers to lawyers. Project representatives have already held over 80 meetings with interested parties around the world, and they even managed to reach Russia—a meeting with Hedera Hashgraph President Tom Troubridge took place in Moscow on March 6, which reportedly gathered many representatives from our IT and financial circles.
Mr. Troubridge stated that no fewer than 40 decentralized applications based on Hedera Hashgraph are expected to launch soon, and there are more than 100 in development. Therefore, in the foreseeable future, everyone will have a chance to see how this technology works firsthand.
Total
Overall, it can be confidently stated that several things are true. First, the project is non-trivial and has already attracted significant interest from representatives of large corporations. Second, for a layperson, it is frankly quite obscure, which seemingly explains the lack of available data about it publicly (and also, judging by the video with Mr. Limón, that this smart gentleman is not exactly an orator). Third, it is unlikely that it will become the 'Bitcoin killer' or something equally grandiose, but its claimed advantages seem substantial enough to warrant close attention to the project.
Moreover, there are rumors that the organizers are planning to attract yet another tranche of investments, and it might very well make sense to participate in it.
Source: habr.com
