With the prosperity of the blockchain, another technology DAG has also gained attention, as well as the Hashgraph technology based on its invention.
The most famous company using this technology should beHedera Hashgraphup. The company received funding from institutions such as BlockTower Capital, Danhua Capital, Digital Currency Group and PV Ventures last year.According to public information。
According to public informationimage description
Leemon Baird (picture via Hedera Youtube)
Many opinions in the market believe that Hedera Hashgraph is an alliance chain or a private chain, and it only serves large enterprises.
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Improve performance with hashmap
Hashgraph is not a blockchain. Mance tried to clarify the misunderstandings of many people in the first sentence: "Hashgraph is another solution (Alternative) outside the blockchain. It is not a blockchain, but it solves The same problem. Our co-founders invented the hash graph in 2012. The purpose is to find a consensus algorithm that satisfies a certain level of security while maximizing performance. In 2015, this solution came out.”
"Bitcoin can process 7 transactions per second, Ethereum can process 15 transactions, and we can achieve 100,000 transactions." Hedera Hashgraph emphasizes speed most. "But the transaction confirmation delay is only a few seconds."
As mentioned earlier, a hashgraph is an improved data structure based on a Directed Acyclic Graph (DAG). This data structure has no concept of blocks, and you can also see it as a block with only one transaction , the transaction can choose to be linked to any one or more old transactions, verified by the new transaction and referenced to the old transaction to complete the verification, referred to as "DAG consensus". This allows temporary small differences between users' ledgers, which weakens the consistency of data blocks across the network in a short period of time, making it less prone to congestion and increasing transaction concurrency. Obviously, the disadvantage of the DAG consensus is that when the transaction frequency is low, it is difficult for old transactions to be verified in time.
Hashgraph uses the Gossip protocol + virtual voting.
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Gossip agreement + virtual voting (picture from Hedera Youtube)
According to public information
According to public information, the benefits of the Gossip protocol are scalability, natural fault tolerance and fast message propagation speed; the disadvantages are message delay and redundancy. Since the state of a transaction is not necessarily the same for each node at a certain moment, but one node will reach the entire network until a transaction is confirmed, the result is called "asynchronous Byzantine".
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Gradually transition from alliance chain to public chain
At present, there are three main doubts and doubts about Hedera Hashgraph in the market:
1. Degree of decentralization: Is Hedera an alliance chain or a private chain, and only serves large enterprises?
Mance said that is not the case. It is undeniable that Hedera has a lot of enterprise-level customer resources, but in fact, Hedera’s strategy is to hope that both top-down and bottom-up routes of large enterprises and start-up companies will be considered, but there will indeed be a route that will be gradually promoted. stage.
Private chain (private network)
Hedera's business was initially focused on private networks. Mance revealed that they deployed a private chain in cooperation with Credit Union in the United States in 2015.
Alliance chain (permission chain)
"In 2017, we decided to release the public chain Hedera. We established the company Hedera Hashgrpah."
This chain is actually already online, but it is not in the form of a public chain, but an alliance chain. Hedera calls this the testnet, “There are more than 300 distributed applications on the testnet, all of which are deployed by large companies that Hedera cooperates with, covering health, digital rights management, security tokens, supply chains, games and other fields.”
The governance mechanism designed by Hedera is slightly different from that of general public chains. Mance explained that they hope to select 39 international companies from 18 industries in different regions of the world to become nodes and also join the governance committee. The market value of these committee members is at least more than 10 billion U.S. dollars, and they have only 6-year terms. The committee designs the product roadmap, how to charge, how to pay, and also manages the property of the network (a bit like the Ministry of Finance). "They are co-owners of this business and can fire the CEO, which is me. Haha."
Last month, Hedera announced the committee's five corporate members, including Deutsche Telekom, DLA Piper, Brazil's e-commerce platform Magazine Luiza, and Japan's Nomura Holdings, Inc. Swisscom Blockchain AG, a Swisscom blockchain company founded by the Swisscom giant.
public permission chain
Now, every user in the network needs to go through KYC and AML. "After the mainnet is released in the summer, we will no longer register personal information, and each account will only have one code name with us."
This summer, the Hedera mainnet will be launched. At that time, everyone can create a Hedera account (and purchase Hedera's utility token). Developers can also use Hedera by calling the API, etc., all need to spend the utility token HBAR Token of the Hedera main network to pay. Interestingly, although the payment is in token, it is denominated in legal currency.
At this time, everyone can open an account and call the API, but not everyone can be a node. "Sounds a bit like WeChat." Hearing me say that, Mance didn't deny it. "The difference is our governance structure. So we call it a public permission chain."
Public chain (permissionless chain)
To become a public chain, Mance revealed that the vision of Hedera will be realized after the implementation of sharding on the main network, about 18 months to 2 years later.
"The current plan for the first batch of committee members is 39; if it is sharded in the future, each group will have 100-1000 nodes." At that time, everyone can become a node of the network.
"We think that the public-private dispute is meaningless, because the two should be combined together, what are the scenarios." Mance emphasized that it is not necessary to put all the content on the public chain: "We will focus on mixing in the future. On the Internet, combine the public chain and the private chain.”
Hedera plans to publish the first version of the source code after the mainnet goes live; however, it may be two years before developers can directly become Hedera nodes to view the code. For some developers, the fact that the code is publicly auditable is a very important factor in choosing a network. Compared to networks that are already free to join, such as Ethereum and EOS, Hedera is undoubtedly slow.
Mance said frankly that developers who are very concerned about this point really have to wait until Hedera implements sharding. "However, for the stability and usability of the network, we don't want to release the network too early."He also added that, in fact, developers are most concerned about stability, especially large companies.
2. Security: How to prevent Sybil attacks? This is another doubt about Hashgraph from the outside world.
Malicious nodes may attempt to compromise the system by manipulating multiple nodes and influence any majority-based decision-making process. This is what is commonly referred to as Sybil Attacks.
In order to save transaction costs, Hedera chose the PoS mechanism. "Because we use PoS instead of PoW, our cost per transaction is the lowest, only 0.0001 cents."
However, the initial security problem of PoS is that the distribution of tokens must be sufficiently decentralized, otherwise if most of the stake is concentrated in the hands of a few people, the risk of being attacked by Sybil is high.
Mance told Odaily that Hedera released the main network in August last year. The upper limit of token issuance is 50 billion coins. Hedera’s Ministry of Finance will hold 94%. The first 6% will be issued, and then gradually issued. By the end of the year, it will become 10%; until 4-5 years later, about 1/3 will be issued. "In this way, our token holdings are wide enough to prevent Sybil attacks. (Hedera's security boundary is that the malicious stake in the network is less than 1/3.)"
3. Too good to be true: Can Hashgraph really be so fast?
The TPS of most public chains is only a few thousand, but Hedera says it can reach 100,000. This makes many public chain projects suspicious. After all, gossip itself has more history of gossip, and the transmission volume is only much higher than that of Bitcoin. Therefore, it is believed that this is mainly because Hedera is an alliance chain.
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Large company resources with obvious advantages
Even though Hedera hopes to seize the individual developer market, it is undeniable that its main advantage now lies in the resources of large companies.
In addition to inviting several large multinational companies to join the committee and deploy applications on the chain, Hedera also invited members of the B-side service giant Oracle's blockchain team to join its team.
“Lionel Chocron, Oracle’s former vice president of innovation, is our CPO (Chief Product Officer), she joined us a month ago; we also hired two of her deputies, one in charge of product, one in charge of industry and cooperation Partners, they used to deal with big companies, but now they deal with our various system integrators.”
Cooperating with universities is also the direction Hedera is working on. The cooperative universities are not only in the United States, but also many Chinese universities.
All in all, Hedera believes that the application of blockchain still has a long way to go.
"Last year was really challenging, and many companies were unwilling to join our governance committee." Jason recalled that it was not easy to persuade large companies to take the first step. And now, when asked what he thinks is the biggest problem with the large-scale application of blockchain, Mance replied:
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I am Lu Xiaoming, editor of Odaily. I am exploring the real blockchain. Please add lohiuming for breaking news and communication. Please note your name, unit, position and reason.
Reference article:
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