Original article here: https://medium.com/wanchain-foundation/ama-with-wanchain-vp-lini-58ada078b4fe
“What is unique about us is that we have actually put theory into practice.”
— Lini
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Wanchain’s Vice President of Business Development, Lini, sat down with blockchain media organization Neutrino for an AMA covering a wide range of topics concerning Wanchain’s development.
The following is an English translation of the original Chinese AMA which was held on December 13th, 2018:
Neutrino: Could you please first share with us a little basic background, what are the basic concepts behind cross chain technology? What are the core problems which are solved with cross-chain? In your opinion, what is the biggest challenge of implementing cross chain to achieve value transfer between different chains?
Lini: Actually, this question is quite big. Let me break it down into three smaller parts:
- First, what is the meaning of “cross-chain”?
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In China, we like to use the word “cross-chain”, the term “interoperability” is used more frequently in foreign countries. Interoperability is also one of the important technologies identified by Vitalik for the development of a future blockchain ecosystem mentioned in the Ethereum white paper. So cross-chain is basically the concept of interoperability between chains.
- The core problem solved by cross chain is that of “multi-ledger” synchronous accounting
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In essence, blockchain is a distributed bookkeeping technique, also known as distributed ledger technology. Tokens are the core units of account on each chain, there currently exist many different chains, each with their own token. Of especial importance is the way in which each ledger uses tokens to interact with each other for the purpose of clearing settlements.
- The core purpose of the cross-chain technology is as one of the key infrastructures of the future economy based on digital currencies.
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Cross chain technology is one of the foundational technological infrastructures that is necessary for the large scale application of blockchain technology.
Neutrino: As we all know, there are many different kinds of cross-chain technologies. Please give us a brief introduction to several popular cross-chain technologies on the market, and the characteristics of each of these technologies。
Lini: Before answering this question, it is very important to share two important concepts with our friends: heterogeneity and homogeneity, and centralization and decentralization.
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These two points are especially important for understanding various cross-chain technologies, because there are many different technologies and terminologies, and these are some of the foundational concepts needed for understanding them.
There are also two core challenges which must be overcome to implement cross-chain:
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Combining the above two points, we look at the exploration of some solutions in the industry and the design concepts of other cross-chain projects.
First I’d like to discuss the Relay solution.
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However the Relay solution must consume a relatively large amount of gas to read the BTC header. Another downside is that, as we all know, Bitcoin’s blocks are relatively slow, so the time to wait for verification will be long, it usually takes about 10 minutes to wait for one block to confirm, and the best practice is to wait for 6 blocks.
The next concept is the idea of Sidechains.
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This solution is good, but not all chains contain SPV, a simple verification method. Therefore, there are certain drawbacks. Of course, this two way peg way solves challenge beta very well, that is, the atomicity of the transaction.
These two technical concepts have already been incorporated into a number of existing cross chain projects. Let’s take a look at two of the most influential of these.
The first is Polkadot.
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This is just a summary based on Polkadot’s whitepaper and most recent developments. The theoretical design is very good and can solve challenges alpha and beta. Last week, Neutrino organized a meetup with Polkadot, which we attended. In his talk, Gavin’s focus was on governance, he didn’t get into too much technical detail, but Gavin shared some very interesting ideas about chain governance mechanisms! The specific technical details of Polkadot may have to wait until after their main net is online before it can be analyzed.
Next is Cosmos.
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Cosmos is a star project who’s basic concept is similar to Polkadot. Cosmos’s approach is based on using a central hub. Both projects both take into account the issue of heterogeneous cross-chain transactions, and both have also taken into account how to solve challenges alpha and beta.
To sum up, each research and project team has done a lot of exploration on the best methods for implementing cross-chain technology, but many are still in the theoretical design stage. Unfortunately, since the main net has not launched yet, it is not possible to have a more detailed understanding of each project’s implementation. A blockchain’s development can be divided into two parts: theoretical design, and engineering implementation. Therefore, we can only wait until after the launch of each project’s main network, and then analyze it in more detail.
Neutrino: As mentioned in the white paper, Wanchain is a general ledger based on Ethereum, with the goal of building a distributed digital asset financial infrastructure. There are a few questions related to this. How do you solve Ethereum’s scaling problem? How does it compare with Ripple, which is aiming to be the standard trading protocol that is common to all major banks around the world? As a basic potential fundamental financial infrastructure, what makes Wanchain stand out?
Lini: This question is actually composed of two small questions. Let me answer the first one first.
- Considerations about TPS.
First of all, Wanchain is not developed on Ethereum. Instead, it draws on some of Ethereum’s code and excellent smart contracts and virtual machine EVM and other mature technical solutions to build the mainnet of Wanchain.
The TPS of Ethereum is not high at this stage, which is limited by various factors such as the POW consensus mechanism. However, this point also in part is due to the characteristics of Ethereum’s very distributed and decentralized features. Therefore, in order to improve TPS, Wanchain stated in its whitepaper that it will launch its own POS consensus, thus partially solving the performance issues related to TPS. Wanchain’s POS is completely different from the POS mechanism of Ethereum 2.0 Casper.
Of course, at the same time, we are also paying close attention to many good proposals from the Ethereum community, such as sharding, state channels, side chains, and the Raiden network. Since blockchain exists in the world of open source, we can of course learn from other technological breakthroughs and use our own POS to further improve TPS. If we have some time at the end, I’d love to share some points about Wanchain’s POS mechanism.
- Concerning, Ripple, it is completely different from what Wanchain hopes to do.
Ripple is focused on exchanges between different fiat pairs, the sharing of data between banks and financial institutions, as a clearing and settlement system, and also for the application of DLT, for example the Notary agent mechanism.
Wanchain is focused on different use cases, it is to act as a bridge between different tokens and tokens, and between assets and tokens. For various cross-chain applications it is necessary to consume WAN as a gas fee to pay out to nodes.
So it seems that the purpose Ripple and Wanchain serve are quite different. Of course, there are notary witnesses in the cross-chain mechanism, that is, everyone must trust the middleman. Ripple mainly serves financial clients, banks, so essentially everyone’s trust is already there.
Neutrino: We see that Wanchain uses a multi-party computing and threshold key sharing scheme for joint anchoring, and achieves “minimum cost” for integration through cross-chain communication protocols without changing the original chain mechanism. What are the technical characteristics of multi-party computing and threshold key sharing? How do other chains access Wanchain, what is the cross-chain communication protocol here? What is the cost of “minimum cost?
Lini: The answer to this question is more technical, involving a lot of cryptography, I will try to explain it in a simple way.
- About sMPC -
It stands for secure multi-party computation. I will explain it using an example proposed by the scholar Andrew Yao, the only Turing Award winner in China. The scenario called Yao’s Millionaire Problem. How can two millionaires know who is wealthier without revealing the details of their wealth to each other or a trusted third party? I’m not going to explain the answer in detail here, but those who are interested can do a web search to learn more.
In sMPC multiple parties each holding their own piece of private data jointly perform a calculation (for example, calculating a maximum value) and obtain a calculation result. However, in the process, each party involved does not leak any of their respective data. Essentially sMPC calculation can allow for designing a protocol without relying on any trusted third parties, since no individual ever has access to the complete private information.
Secure multiparty computing can be abstractly understood as two parties who each have their own private data, and can calculate the results of a public function without leaking their private data. When the entire calculation is completed, only the calculation results are revealed to both parties, and neither of them knows the data of the other party and the intermediate data of the calculation process. The protocol used for secure multiparty computing is homomorphic encryption + secret sharing + OT (+ commitment scheme + zero knowledge proofs, etc.)
Wanchain’s 21 cross chain Storeman nodes use sMPC to participate in the verification of a transaction without obtaining of a user’s complete private key. Simply put, the user’s private key will have 21 pieces given to 21 anonymous people who each can only get 1/21 part, and can’t complete the whole key.
- Shamir’s secret sharing
There are often plots in a movie where a top secret document needs to be handed over to, let’s say five secret agents. In order to protect against the chance of an agent from being arrested or betraying the rest, the five agents each hold only part of a secret key which will reveal the contents of the documents. But there is also a hidden danger: if one the agents are really caught, how can the rest of the agents access the information in the documents? At this point, you may wonder if there is any way for the agents to still recover the original text with only a portion of the keys? In other words, is there any method that allows a majority of the five people to be present to unlock the top secret documents? In this case, the enemy must be able to manipulate more than half of the agents to know the information in the secret documents.
Wanchain uses the threshold M<=N; N=21; M=16. That is to say, at least 16 Storeman nodes must participate in multi-party calculation to confirm a transaction. Not all 21 Storeman nodes are required to participate. This is a solution to the security problem of managing private keys.
Cross-chain communication protocols refers to the different communication methods used by different chains. This is because heterogeneous cross-chain methods can’t change the mechanism of the original chains. Nakamoto and Vitalik will not modify their main chains because they need BTC and ETH interoperability. Therefore, project teams that can only do cross-chain agreements to create different protocols for each chain to “talk”, or communicate. So the essence of a cross-chain protocol is not a single standard, but a multiple sets of standards. But there is still a shared sMPC and threshold design with the Storeman nodes.
The minimum cost is quite low, as can be shown with Wanchain 3.0’s cross chain implementation. In fact it requires just two smart contracts, one each on Ethereum and Wanchain to connect the two chains. To connect with Bitcoin all that is needed is to write a Bitcoin script. Our implementation guarantees both security and decentralization, while at the same time remaining simple and consuming less computation. The specific Ethereum contract and Bitcoin scripts online can be checked out by anyone interested in learning more.
Neutrino: What kind of consensus mechanism is currently used by Wanchain? In addition, what is the consensus and incentive mechanism for cross-chain transactions, and what is the purpose of doing so? And Wanchain will support cross-chain transactions (such as BTC, ETH) on mainstream public chains, asset cross-chain transactions between the alliance chains, and cross-chain transactions between the public and alliance chains, how can you achieve asset cross-chain security and privacy?
Lini: It is now PPOW (Permissioned Proof of Work), in order to ensure the reliability of the nodes before the cross-chain protocol design is completed, and to prepare to switch to POS (as according to the Whitepaper roadmap). The cross-chain consensus has been mentioned above, with the participation of a small consensus (at least 16 nodes) in a set of 21 Storeman nodes through sMPC and threshold secret sharing.
In addition, the incentive is achieved through two aspects: 1) 100% of the cross chain transaction fee is used to reward the Storeman node; 2) Wanchain has set aside a portion of their total token reserve as an incentive mechanism for encouraging Storeman nodes in case of small cross-chain transaction volume in the beginning.
It can be revealed that Storeman participation is opening gradually and will become completely distributed and decentralized in batches. The first phase of the Storeman node participation and rewards program is to be launched at the end of 2018. It is expected that the selection of participants will be completed within one quarter. Please pay attention to our official announcements this month.
In addition, for public chains, consortium chains, and private chains, asset transfer will also follow the cross-chain mechanism mentioned above, and generally follow the sMPC and threshold integration technology to ensure cross-chain security.
When it comes to privacy, this topic will be bigger. Going back to the Wanchain Whitepaper, we have provided privacy protection on Wanchain mainnet. Simply put, the principle is using ring signatures. The basic idea is that it mixes the original address with many other addresses to ensure privacy. We also use one-time address. In this mechanism a stamp system is used that generates a one-time address from a common address. This has been implemented since our 2.0 release.
But now only the privacy protection of native WAN transactions can be provided. The protection of cross-chain privacy and user experience will also be one of the important tasks for us in 2019.
Neutrino: At present, Wanchain uses Storeman as a cross-chain trading node. Can you introduce the Storeman mechanism and how to protect these nodes?
Lini: Let me one problem from two aspects.
- As I introduced before in my explanation of sMPC, the Storeman node never holds the user’s private key, but only calculates the transaction in an anonymous and secure state, and the technology prevents the Storeman nodes from colluding.
- Even after technical guarantees, we also designed a “double protection” against the risk from an economic point of view, that is, each node participating as a Storeman needs to pledge WAN in the contract as a “stake”. The pledge of WAN will be greater than the amount of any single transaction as a guarantee against loss of funds.
If the node is malicious (even if it is a probability of one in a billion), the community will be compensated for the loss caused by the malicious node by confiscation of the staked WAN. This is like the POS mechanism used by ETH, using staking to prevent bad behavior is a common principle.
Neutrino: On December 12th, the mainnet of Wanchain 3.0 was launched. Wanchain 3.0 opened cross-chain transactions between Bitcoin, Ethereum and ERC20 (such as MakerDao’s stable currency DAI and MKR). What does this version mean for you and the industry? This upgrade of cross-chain with Bitcoin is the biggest bright spot. So, if now you are able to use Wanchain to make transactions between what is the difference between tokens, then what is the difference between a cross chain platform like Wanchain and cryptocurrency exchanges?
Lini: The release of 3.0 is the industry’s first major network which has crossed ETH and BTC, and it has been very stable so far. As mentioned above, many cross-chain, password-protected theoretical designs are very distinctive, but for engineering implementation, the whether or not it can can be achieved is a big question mark. Therefore, this time Wanchain is the first network launched in the world to achieve this. Users are welcome to test and attack. This also means that Wanchain has connected the two most difficult and most challenging public networks. We are confident we will soon be connecting other well-known public chains.
At the same time of the release of 3.0, we also introduced cross chain integration with other ERC20 tokens in the 2.X version, such as MakerDao’s DAI, MKR, LRC, etc., which also means that more tokens of excellent projects on Ethereum will also gradually be integrated with Wanchain.
Some people will be curious, since Wanchain has crossed so many well-known public chains/projects; how is it different with crypto exchanges? In fact, it is very simple, one centralized; one distributed. Back to the white paper of Nakamoto, is not decentralization the original intention of blockchain? So what Wanchain has to do is essentially to solve the bottom layer of the blockchain, one of the core technical difficulties.
Anyone trying to create a DEX (decentralized exchange); digital lending and other application scenarios can base their application on Wanchain. There is a Wanchain based DEX prototype made by our community members Jeremiah and Harry, which quite amazing. Take a look at this video below.
https://www.youtube.com/watch?v=codcqb66G6Q
Neutrino: What are the specific application use cases after the launch of Wanchain 3.0? Most are still exploring small-scale projects. According to your experience, what are the killer blockchain applications of the future? What problems need to be solved during this period? How many years does it take?
Lini:
- Wanchain is just a technology platform rather than positioning itself as an application provider; that is, Wanchain will continue to support the community, and the projects which use cross-chain technology to promote a wide range of use cases for Wanchain.
- Cross-chain applications that we anticipate include things like: decentralized exchanges, digital lending, cross chain games, social networking dAPPs, gambling, etc. We also expect to see applications using non fungible tokens, for example exchange of real assets, STOs, etc.
- We recently proposed the WanDAPP solution. Simply speaking, a game developer for example has been developing on Ethereum, and ERC20 tokens have been issued, but they hope to expand the player base of their games to attract more people. To participate and make full use of their DAPP, you can consider using the WanDAPP solution to deploy the game DAPP on other common platforms, such as EOS, TRON, etc., but you don’t have to issue new tokens on these chains or use the previous ERC20 tokens. In this way the potential user population of the game can be increased greatly without issuing more tokens on a new chain, improving the real value of the original token. This is accomplished completely using the cross-chain mechanism of Wanchain.
- For large-scale applications, the infrastructure of the blockchain is not yet complete, there are issues which must first be dealt with such as TPS, sharding, sidechains, state channels, etc. These all must be solved for the large-scale application of blockchain applications. I don’t dare to guess when it will be completed, it depends on the progress of various different technical projects. In short, industry practitioners and enthusiasts need a little faith and patience.
Neutrino community member Block Venture Capital Spring: Will Wanchain be developing any more cross chain products aimed at general users? For example will the wallet be developed to make automatic cross chain transfers with other public chains? Another issue the community is concerned about is the currency issuance. Currently there are more than 100 million WAN circulating, what about the rest, when will it be released?
Lini: As a cross-chain public chain, we are not biased towards professional developers or ordinary developers, and they are all the same. As mentioned above, we provide a platform as infrastructure, and everyone is free to develop applications on us.
For example, if it is a decentralized exchange, it must be for ordinary users to trade on; if it is some kind of financial derivatives product, it is more likely to be used by finance professionals. As for cross-chain wallets which automatically exchange, I’m not sure if you are talking about distributed exchanges, the wallet will not be “automatic” at first, but you can “automatically” redeem other tokens.
Finally, the remaining WAN tokens are strictly in accordance with the plan laid out in the whitepaper. For example, the POS node reward mentioned above will give 10% of the total amount for reward. At the same time, for the community, there are also rewards for the bounty program. The prototype of the DEX that I just saw is a masterpiece of the overseas community developers, and also received tokens from our incentive program.
Neutrino community member’s question: There are many projects in the market to solve cross-chain problems, such as: Cosmos, Polkadot, what are Wanchain’s advantages and innovations relative to these projects?
Lini: As I mentioned earlier, Cosmos and pPolkadot all proposed very good solutions in theory. Compared with Wanchain, I don’t think that we have created anything particularly unique in our theory. The theoretical basis for our work is cryptography, which is derived from the academic foundation of scholars such as Yao Zhizhi and Silvio Micali. Our main strong point is that we have taken theory and put it into practice..
Actually, the reason why people often question whether a blockchain project can be realized or not is because the whitepapers are often too ambitious. Then when they actually start developing there are constant delays and setbacks. So for us, we focus on completing our very solid and realizable engineering goals. As for other projects, we hope to continue to learn from each other in this space.
Neutrino community member Amos from Huobi Research Institute question: How did you come to decide on 21 storeman nodes?
Lini: As for the nodes we won’t make choices based on quantity alone. The S in the POS actually also includes the time the tokens are staked, so that even if a user is staking less tokens, the amount of time they stake them for will also be used to calculate the award, so that is more fair. We designed the ULS (Unique Leader Selection) algorithm in order to reduce the reliance on the assumption of corruption delay (Cardano’s POS theory). which is used for ensuring fairness to ensure that all participants in the system can have a share of the reward, not only few large token holders.
Wu Di, a member of the Neutrino community: Many big exchanges have already begun to deploy decentralized exchanges. For example, Binance, and it seems that the progress is very fast. Will we be working with these influential exchanges in the future? We we have the opportunity to cooperate with them and broaden our own influence?
Lini: I also have seen some other exchange’s DEX. Going back the original point, distributed cross-chain nodes and centralized ones are completely different. I’m guessing that most exchanges use a centralized cross-chain solution, so it may not be the same as the 21 member Storeman group of Wanchain, but I think that most exchanges will likely be using their own token and exchange system. This is my personal understanding. But then, if you are developing cross chain technology, you will cooperate with many exchanges that want to do a DEX. Not only Binance, but also Huobi, Bithumb, Coinbase… And if there is anyone else who would like to cooperate we welcome them!
Neutrino community member AnneJiang from Maker: Dai as the first stable chain of Wanchain will open a direct trading channel between Dai and BTC. In relation to the Dai integration, has any new progress has been made on Wanchain so far?
Lini: DAI’s stable currency has already been integrated on Wanchain. I just saw it yesterday, let me give you a picture. It’s on the current 3.0 browser, https://www.wanscan.org/, you can take a look at it yourself.
This means that users with DAI are now free to trade for BTC, or ETH or some erc20 tokens. There is also a link to the Chainlink, and LRC is Loopring, so basically there are quite a few excellent project tokens. You may use the Wanchain to trade yourself, but since the DEX is not currently open, currently you can only trade with friends you know.
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About Neutrino
Neutrino is a distributed, innovative collaborative community of blockchains. At present, we have established physical collaboration spaces in Tokyo, Singapore, Beijing, Shanghai and other places, and have plans to expand into important blockchain innovation cities such as Seoul, Thailand, New York and London. Through global community resources and partnerships, Neutrino organizes a wide range of online an offline events, seminars, etc. around the world to help developers in different regions better communicate and share their experiences and knowledge.
About Wanchain
Wanchain is a blockchain platform that enables decentralized transfer of value between blockchains. The Wanchain infrastructure enables the creation of distributed financial applications for individuals and organizations. Wanchain currently enables cross-chain transactions with Ethereum, and today’s product launch will enable the same functionalities with Bitcoin. Going forward, we will continue to bridge blockchains and bring cross-chain finance functionality to companies in the industry. Wanchain has employees globally with offices in Beijing (China), Austin (USA), and London (UK).
You can find more information about Wanchain on our website. Additionally, you can reach us through Telegram, Discord, Medium, Twitter, and Reddit. You can also sign up for our monthly email newsletter here.
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