Grin, as the first implementation of privacy-oriented protocol Mimblewimble along with Beam, has been one of the few highlights amid the crypto winter since its mainnet went at the beginning of the year. Started in late 2016, the cryptocoin prides itself for a community-driven project that is “launched fairly, free of ICO, pre-mine or founder’s reward”.

Though credited as a promising crypto, Grin coin’s endless supply has plagued a majority of potential investors, including a large number of Chinese miners. On March 14, 8btc, the earliest bitcoin social media in China, invited the development team of Grin, together with the CEO of BTC.com Zhuang Zhong, one of the earliest mining pools to support Grin mining, to hold an online AMA (Ask Me Anything) with the Chinese crypto community.

Questions about no maximum cap have been heatedly discussed in the AMA. Regarding this, Grin developers stressed that “supply itself is not important, but rather the predictability of its emission”. According to Gary Yu, after 10 years, Grin will have a lower inflation rate compared with U.S. dollar.

Grin: be a “better money”

Q1. What’s the main pain point Grin addressees?

Yeastplume: Basically, Grin is trying to be ‘better money’. Grin is well known as an implementation of the very new Mimblewimble protocol, but it’s also contains many learnings from an evolution of chains that’s come before it. A lot of the technologies in Grin are evolutionary improvements to other coins. For instance, many privacy coins are built on top of a Bitcoin-style blockchain, and the privacy features are built on top of that (sometimes as an option as opposed to being the default), which in some cases can lead to very large blockchain sizes. With Grin, thanks to Mimblewimble, the privacy is built directly into the core protocol in a very compact and elegant way that minimizes bloat. It also allows all sorts of other size and efficiency improvements, such as fast sync and node pruning. So I wouldn’t say Grin is trying to solve a particular set of pain points, but it is generally trying to improve on all aspects of running and using a privacy-based cryptocurrency. So I would say the main pain point addressed is lack of privacy in other coins. But also the reduced scalability in other privacy coins,（and lastly, I see it addressing the pain point of complexity）

Q2. What’s the plan and frequency of Grin network updates in following days？

Hashmap: We have reserved 4 (or 3? could be off-by-one error on my side) slots in the first 2 years (every 6 months) for potential hard forks (tweaks in Cuckaroo29 and perhaps something else consensus breaking). Each of them may or may not happen. Besides that we update the node and wallet code quite regularly, so users are advised to update to get the best grin experience.

Q3. What’s the current state of Grin Foundation and the usage of raised funds?

Lehnberg: We track our funding campaigns on the project website, and also track income and spending in detailed financial logs on our project management repository. We celebrate all our donors on our Friends of Grin page where a Hall of Fame was just introduced to give special recognition to the donors who have made very significant contributions to the project. That said, all donations are most welcome, big or small. And we are thinking about ways to give recognition to donations beyond just money, like for example companies who donate some of their employees’ time to work on Grin. So far, the only spends that have been signed off on has been to fund security audits of our code, and to fund developers. All funding decisions are discussed in the open. I expect that the funding efforts for the foreseeable future will focused on supporting protocol development, like for example to fund engineers. To clarify in case it’s not obvious: Grin has no foundation. There’s no company. There’s no legal identity or official organization. We explored foundations in the past and decided it did not make sense for us to have this. https://github.com/mimblewimble/docs/wiki/Regarding-Foundations

Q4. In terms of compliance, what will Grin do as a privacy coin?

Lehnberg: Physical cash has existed for a long time. Is cash compliant? I would say cash is neutral or indifferent to compliance. It’s not cash that needs to be compliant with a particular regulation, it’s the people and businesses that use cash. Similarly, I don’t think compliance is a matter for Grin, but for its users.

Q5. Grin started late, and chose to launch in a bear market, is there any intention behind it? In addition, Grin is only listed on some small exchanges at present. Will Grin get listing on major ones like Huobi, Binance and OKEx in the foreseeable future? In other words, do you have any plans to try and gain access to these exchanges?

Quentin Le Sceller: Ignotus Peverell started Grin in October 2016. So this new cryptocurrency has been developed for more than 2 and a half years. We did not specifically choose to launch in a bear market, it was just time for Grin to be launched. Regarding the exchanges, Grin team does not work directly with exchanges for listing. If you’d like Grin to be listed on one of these exchanges, I invite you to contact them.

Bitcoin get Mimblewimble?

Q6. There have been established privacy coins like DASH,XMR and ZEC in the market, how can you stand out from the rest?

Yeastplume: Grin is 100% community funded, there’s no pre-mine or dev tax, so I think the community has more reassurance that any decisions that are made about Grin are made for the long-term health of the coin rather than short-term gains for a small group of people

Q7. Grin and Beam have been around for about the same time and share a lot of similarities in technology. What does Grin team think about Beam which gets funds from venture capitalist?

John Tromp: We think there’s plenty room for multiple MW implementations, and although we disagree with their funding model, BEAM is making worthwhile additions to the MW design space with an original codebase, different choices of consensus critical data structures, and experimental features.

Q8. The MimbleWimble technology was first presented by the bitcoin dev team, but why don’t they adopt it themselves? Are there any difficulties in technology implementation?

Quentin Le Sceller: Originally the Mimblewimble technology was created Tom Elvis Jedusor back in August 2016. Later on Andrew Poelstra presented it at Scaling Bitcoin 2016 (so I’m not sure the question is correct in stating that MW was originally presented by Bitcoin dev). So why Bitcoin did not implemented it? We don’t know if Bitcoin will ever implement MW but I’d say that it is very unlikely in the short term. Bitcoin development is very conservative. Implementing MW in Bitcoin would likely requires major changes in the code. This would also mean that all the scripting language used in Bitcoin will not work too (as MW has no scripting language). Also confidential transactions (one of the pillars of MW) are larger than Bitcoin transactions.

Q9. Do you see other mainstream coins like BTC, ETH and BCH as competitors to Grin?

Lehnberg: We don’t see other teams and projects as competitors. Grin is focused to become better money. This is not a zero-sum game, and I personally welcome ways to be able to co-operate and work with other projects.

Grin will have a lower inflation rate compared with U.S. dollar?

Q10. How can a constant inflation model guarantee Grin’s survivability in the first years?

John Tromp: In coming years, emission is constant like in early history of all coins. Monero is also surviving well with continuous inflation. I think ppl will come to realize that putting an end to inflation in some distant future (2140 for bitcoin) has negligible effect on survivability. Hashmap: and it’s not really unlimited, it’s limited by time, what really matters is predictability of the supply. Yeastplume: Also, nobody has definitively shown that fees alone will be enough to secure a coin once block rewards have gone too low, which may even make Grin more likely to survive. Gary Yu: Simplicity is a big part of Grin’s design and a constant emission is by far the simplest. Other emission schedules seem rather arbitrary and there are no science or study can definitely show which emission schedule is optimal. There are studies that have shown that having zero emission after a while can be dangerous however. Short emissions schedules seem to unfairly reward early adopters. And look into a picture made by CryptoProfG For the 1st 10 years, Grin will have only issued about 54% more coins than Bitcoin (410=40 vs 44+24+12=26). This is certainly negligible compared to price fluctuation in 10 years, thinking about a 10% fluctuation often seen in just one day in current crypto market. After 10 years, Grin will have a lower inflation rate compare with US$. I really think Grin’s constant emission design is great!

Q11. The inflation model directly contradicts “Satoshi’s Vision”. Will this inflation model make the “bubble” bigger and burst one day? On the other hand, the unlimited cap also discourages people from hoarding coins, so will it affect Grin demand and thus lead to the excessive supply in the market, or even dying?

John Tromp: No Yeastplume: Firstly, Satoshi was an engineer or developer putting together the first iteration of a new concept. He couldn’t see into the future to know all of his assumptions were correct, nor was the inflation model handed to him on a tablet from God. As for the rest, I think those have already been answered. The supply itself is not important, but rather the predictability of its emission. So long as that’s predictable, anything can be priced in. Gary Yu: For long term, Grin has a great potential to be a much better MOE (medium of exchange) than Bitcoin, while still as a good SOV. And regarding to “Satoshi’s Vision”, the exact one is “Make better money”, not the inflation model, Grin’s solving a lot of Bitcoin’s problem, that’s why a lot of people saying Grin is Bitcoin V2.0, my personal view.

Grin mining: ASIC miners vs. GPU miners

Q12. Why Grin offer two coins for mining (Grin -29 and Grin -31)? What’s the intention of the design?

John Tromp: To maintain competition between ASIC and GPU miners; Both sides will have certain rewards.

Q13. Now there are two algorithms for Grin mining. What could GPU miners do when ASIC is rolled out in the future？

Zhuang Zhong: Ultimately, Grin hope ASIC miners could emerge, and these miners are developed under the situation that the community knows about it. Considering the uncertainty of miner development, the dev team has reserved the option of upgrading corresponding protocol.

Q14. Grin sees obvious decline in its hash power recently, so how can you guarantee it won’t be threatened 51% attack?

John Tromp: A 51% attack only makes economic sense if exchanges hold large balances that can be double spent. With Grin being so young, such large balances should be very rare and perhaps subject to extra precaution by exchanges. Over time, as ASICs are introduced, chances of pulling off a 51% attack will naturally reduce (assuming Grin remains the biggest coin using the Cuckatoo31+ PoW).

Q15. How does Grin network handle transactions and how does the nodes and miners work together? How does Grin validate the transaction and ensure its traceability when necessary? Difficulty adjustment of Grin mining and block output mechanism? What should miners notice about the difference between Grin and other GPU-mined coins ?

Zhuang Zhong: 1.There is no difference between the logic of transaction broadcast and packaging with bitcoin; 2. At present, Grin cannot provide the key for audit like other privacy coins, so it is difficult to trace them. The validation transaction is still based on the UTXO model; 3. One-minute gap for next block, based on the time taken by the last 60 blocks; 4. The Grin mining software is not mature enough as other coins at present, so we need to pay close attention to the software upgrade and the adaption of the mining pool. John Tromp: Difficulty is adjusted every block, based on the time taken by the last 60 blocks, with a factor 3 dampening factor, as expressed in function consensus: next_difficulty at https://github.com/mimblewimble/grin/blob/master/core/src/consensus.rs#L261-L308 4) The Cuckoo Cycle family of PoW is very memory intensive, requiring over 10 GB for Cuckatoo31, and over 5 GB for Cuckaroo29, for optimal efficiency. It appears to favor NVIDIA, in particular the new Turing based RTX cards.3）

Mobile wallet for Grin?

Q16. Will Grin develop a user-friendly wallet?

Yeastplume: Short answer, probably never. Grin is taking a very community-driven approach to wallets. We don’t have UI and/or usability expertise on the core team, so our focus is rather to provide tools and libraries that make life easier for anyone who wants to build wallets and other support software on top of grin… so for instance, here’s Ironbelly: https://cycle42.com/ironbelly a community-developed iOS wallet. That’s just one example there are many more out there. We also think this approach is important, because the need to parties to interact during a Grin transaction can be challenging. There are different ways of facilitating this, some of which may have privacy tradeoffs which may be acceptable to some users but not others. Rather than prescribing a particular approach, we leave it to the community to experiment with different solutions. And to add, I think seeing several community wallets is a far better sign for how popular a coin is is than having the coin developers release an ‘official’ wallet

Q17. How Grin realize anonymous pay？