Original: “Interview with Starknet founder: Look up to the stars, keep your feet on the ground” by Jack
At the recent EDCON conference in Montenegro, ZK became the hottest topic. From the 19th to the 23rd of May, during the five-day event, speakers and guests discussed topics related to ZK Rollup, zkEVM, and ZKML, both in individual presentations and roundtable discussions. In the eyes of the “Ethereum core circle,” ZK has become the ultimate new narrative that is capable of shaking up the next round of industry breakthroughs and is comparable to the 2019 DeFi innovation.
For a long time, the main challenge facing ZK has been technical implementation, which has made it a “future solution” in most people’s minds. However, this year, when the Arbitrum ecosystem has yet to heat up, ZK Rollups, as a technical alternative, have already taken off. The most obvious feeling this year is that there are suddenly more “ZK projects” of all kinds. Developers have started to FOMO ZK technology, and if a project is related to privacy, the project name will definitely contain the word “ZK,” such as ZK transfer, ZK identity, and ZK board games. This prosperous scene is undoubtedly due to the concentrated efforts of ZK Rollups such as Starknet and zkSync, as well as zkEVM projects such as Scroll and Polygon. But behind these pillars of strength is a man named Eli Ben-Ssason from Israel.
Eli (@EliBenSasson) is one of the earliest researchers to combine ZK technology with cryptography. He is the founder of Zcash and StarkWare and the creator of zk-STARK. The latter is an important technical cornerstone of today’s Starknet and the entire ZK encryption track. BlockBeats met this legendary figure during the EDCON conference in Montenegro and in a conversation that lasted nearly an hour, Eli showed strong technical confidence. He revealed to BlockBeats his views on the STARK, SNARK, and Rollup tracks, as well as his expectations for the Starknet ecosystem.
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On optimistic fraud proofs, zk-STARK, and SNARK
Many people are familiar with Eli as the co-founder of StarkWare, but few know that he is also the creator of zk-SNARK, a key technical standard. Long before Ethereum, Eli began combining ZK technology to solve the blockchain scaling problem and had in-depth discussions with Vitalik, who was then a writer for Bitcoin Magazine. StarkWare is also one of the few projects in which Vitalik has participated as an investor.
Eli Ben-Sasson gave a speech at the 2023 StarkWare Sessions conference, image source from StarkWare
As a tech-driven entrepreneur, Eli has absolute confidence in ZK technology and the mathematical principles behind it. So how does he view “ZK rival” Optimistic Rollup? What are his thoughts on the future of zk-STARK and zk-SNARK?
BlockBeats: Hello Eli, first please briefly introduce to readers why you entered the cryptocurrency field and why you founded Zcash and StarkWare?
Eli: I used to be a computer science professor doing research in theoretical computer science. People in mainland China may have heard of Yao Qizhi from Tsinghua University, an important promoter of theoretical computer science, Turing Award winner, and inventor of secure multi-party computation. I entered this research field many years after him.
In 2008, I started doing some research related to zero-knowledge proofs (ZKP). In May 2013, ten years ago, I attended a Bitcoin conference in San Jose and realized that the blockchain field was the best application scenario for my theoretical research, mathematics, and so on. I was very sure that I was the first person to realize that proofs of general computation and blockchain can be combined very well. Ethereum had not yet appeared ten years ago. When I first met Vitalik, he was not the founder of Ethereum but a content author for Bitcoin Magazine. We discussed many issues related to proofs, proofs of validity, and zero-knowledge proofs.
One of my early co-authored papers was called “Zerocash: Decentralized Anonymous Blockingyments from Bitcoin,” which discussed how to use zero-knowledge proofs to protect payments on Bitcoin. This became the Zcash project, and we have been developing this technology ever since. In 2018, we proposed better technical improvements and called it STARK, which helps to scale Ethereum or general blockchains. In 2018, we co-founded StarkWare, with founders including myself, Uri Kolodny, Alessandro Chiesa, and Michael Riabzev. Nowadays, our proofs of validity are widely regarded as the best way to scale Ethereum.
BlockBeats: You mentioned that you had early contact with Vitalik, who was one of the early investors in StarkWare.
Eli: Yes, Vitalik is one of StarkWare’s early investors. This is one of his few investments to date, and we are very proud of it.
I remember Vitalik becoming a core investor around the fall of 2018. We attended a conference together, which was organized by Tsinghua University, I think, but it was definitely in Shenzhen. I remember us walking around a very beautiful seafood market, discussing things like StarkWare, his investments, and a bunch of things. So the details of this decision were reached in China.
BlockBeats: How did you see that there would definitely be scalability issues with blockchain before Ethereum started considering using ZK proofs as a scaling solution?
Eli: I believe readers in the Chinese community must be familiar with Alipay and WeChat Pay. Their transaction speeds may have reached one million transactions per second. Now, blockchain needs to do NFTs, games, voting, elections, and governance. To make all of these happen, the current technology is not good enough. There are about 10 to 20 transactions per second on Bitcoin and Ethereum. This requires other technologies that do not reduce blockchain security, but can expand the scope or reach of blockchain, which is what Starknet does.
BlockBeats: Arbitrum founder Professor Ed Felten also started solving scalability issues around 2014, but he decisively chose interactive fraud proof, which was later widely regarded as the more feasible optimistic fraud proof. Why did you decide to use ZK as a solution from the beginning?
Eli: This is a better technology and it really works. In fact, in the core Ethereum team, everyone knows that Optimistic Rollups did not turn on their core technology. Neither Arbitrum nor Optimistic have fraud proofs. The reason they didn’t turn on is that it doesn’t work at all.
On the contrary, we have never submitted a state update without a STARK validity proof. Even if our system performance reaches 10 times that of Ethereum, we only use less than 1% of Ethereum resources. Optimistic Rollups is a good idea, but it doesn’t work, and it’s not turned on precisely because it doesn’t work. There is a big difference between something that should work but doesn’t work and hasn’t been turned on, and a technology that really works and can be proven.
BlockBeats: But although Vitalik invested in StarkWare, he later supported Optimism. There seems to be a growing consensus in the crypto field that scalability issues should first be addressed with Optimistic, and then move towards ZK, as ZKP or ZK Rollup is much more difficult to implement technically than Optimistic. What do you think about this?
Eli: I like the Optimism team, they are outstanding members of the community, but the technology doesn’t work. It’s like why can’t we attach feathers to people and have them flap their wings to build airplanes? It’s more meaningful, which is why Leonardo da Vinci painted people with wings. But it doesn’t work mathematically and economically. I like and appreciate their intelligence and truly great community members, but it doesn’t change the fact that it’s a technology that can’t work very well.
BlockBeats: But as an ordinary user, Optimism and Arbitrum are indeed practical solutions for now.
Eli: Of course, but what needs to be realized is that your asset security is based on trusting a single operator, and it works very effectively. Here’s another possibility that works well. You can bridge your assets to any computer you trust very much. It can be a centralized exchange or anything similar, and then you will get amazing TPS throughput, but you are entrusting all your funds to the computer controlled by that person. If it fails, goes offline, or acts maliciously, all your funds will be lost.
Arbitrum, Optimism, and Binance have the same security assumptions, and Binance is a good product for users and may even be better than Arbitrum, but it’s important for users not to be fooled into thinking they have a higher level of security when transferring assets. If someone says they won’t use Binance because it’s controlled by a centralized process, they want to go decentralized, they want to put their assets on Arbitrum or Optimism, but it’s actually the same thing.
BlockBeats: So when users use Optimism or Arbitrum, they are actually using a centralized trading platform?
Eli: They are using a centralized system, and worse, it’s based on a codebase that was not designed to be operated by a single operator from the beginning. So I think it provides you with less legal protection than Binance.
BlockBeats: Going back to ZKP, you have created zk-STARK in addition to the widely recognized zk-SNARK. Why did you set two different technical standards for ZK technology, and why did StarkWare ultimately choose zk-STARK?
Eli: SNARKs technology, the Groth-16 type of preprocessed SNARKs, uses elliptic curves and can be prepared for production earlier, but I think it is a less good technology in terms of efficiency and security. It’s like having a technology that isn’t that good, but it comes out first, like a steam engine that isn’t as good as a gasoline engine, but it comes out first. I think it’s somewhat similar.
As for why we chose zk-STARK, it was an easy choice. It has the most secure and future-proof underlying technology, relying on battle-tested mathematics and encryption. It is worth noting that it is post-quantum secure, which other systems cannot achieve. It has the fastest and most efficient proof, and because of this, it reaches the highest level of all proof technologies.
Comparison of zk-STARK and zk-SNARK technical details, image source: Horizon Acadamy
BlockBeats: Many ZK Rollup and zkEVM projects currently use zk-SNARK. What is your view on the future of zk-SNARK?
Eli: I think it will gradually be phased out. It may be left for personal shielded transactions, where users may not care about the inefficiency of proof time in certain cases. And there are indeed very short proofs, about 200 bytes or so. So they may have some use in the privacy area for personal shielded transactions, but once they reach higher throughput, that’s all they can do. All the proof-of-stake projects in the Polygon system, from Hermez, Miden to Polygon Zero and so on, are using STARKs, which we invented. Some projects are currently using SNARKs, but eventually they will all switch to STARKs. So, currently, the largest number of blockchain validity proof projects are using STARKs.
About Starknet, Cairo, and zkEVM
What many people find difficult to understand is that as an Ethereum L2, Starknet itself is not compatible with Ethereum EVM, and developers need to use the new language Cairo to develop contracts. This seems to take away many of the advantages of EVM compatible L1 and Ethereum equivalent L2, namely, to minimize development costs and to launch the ecosystem quickly in a short period of time. But in Eli’s view, these issues become less important in the face of the enormous potential brought by Cairo. More importantly, the Starknet ecosystem has its own solutions to these problems.
BlockBeats: Why did StarkWare create two different projects, StarkEx and Starknet? Why couldn’t they be combined?
Eli: StarkEx and Starknet serve two different purposes. When you’re talking about a very specific kind of high-throughput transaction with a very specific kind of property, such as minting and trading NFTs, then you can get better performance and throughput from a system that’s specifically built for that, and that’s StarkEx. We started from a very specific use case and stress-tested the whole technology around it, and we’re very proud of that.
Starknet, on the other hand, was built more intricately, so it naturally came later, and it serves a different purpose, allowing you to do general computation, like Ethereum, but that kind of general computation means that its performance won’t be as good as specific performance for one use case. So, it’s a trade-off between generality and efficiency.
BlockBeats: So, achieving high transaction TPS in specific use cases is very important for the StarkWare team?
Eli: Yeah, it’s very important for us to achieve that goal. A lot of teams “run their own project on Twitter”, they put out some nice numbers and expect people to be fooled into thinking that it’s an effective system. But we’re proud of the high TPS system we have been running for years. It’s all about improving throughput and reducing transaction costs.
What I mean to say is that so far, our system has processed almost $1 trillion worth of transactions, more than 450 million transactions, and issued more than 100 million NFTs. No other L2 can do that. Our daily TPS is 50% higher than Ethereum, and our weekly TPS is 30% higher than Ethereum, for a whole week. No other system can reach that level, and we’ve never used more than 1% of Ethereum Gas, even when our TPS increased by 30%.
BlockBeats: StarkEx is a very specific use case, and as a technology-driven project, StarkWare seems to have a very clear positioning for its business model from the beginning.
Eli: I like to say “look up at the stars and keep your feet on the ground.” We’re very math-, engineering-, and technology-savvy, and it’s easy to be attracted to the next cool scientific project and like to show off some trendy new things, which is very tempting for me. But we put aside the cool stuff that can’t meet users’ immediate needs and instead focus very hard on providing what users and customers really need. As a scientist, the whole team knows that I’m very regretful because I can’t do things like elliptic curve Fast Fourier Transform (ECFFT), and many quirky technologies that we know can improve performance by 10 times or even 100 times.
Image source: StarkWare
BlockBeats: Next I’d like to talk about Cairo. As an Ethereum L2, Starknet is not compatible with the Ethereum EVM, and developers must use Cairo to build applications. This seems to make Starknet lose many of the advantages of the “EVM-compatible ecosystem.” Why choose to build your own language?
Eli: Yes, I have a few things to say about Cairo. First of all, it is an advanced, next-generation smart contract programming language. It supports some new features from the very beginning, such as smart wallets or account abstraction, which are built into the Cairo language. This is a programming language inspired by Rust, and many developers who have tried Solidity and use it, especially those who know Rust, will say that they prefer to program in Cairo rather than Solidity. So it is already a very, very good programming language.
The second thing I want to say is that the reason for using a dedicated language to create STARK proofs or general validity proofs is similar to why you want to write smart contracts in Solidity. You need to use Solidity not because it has a better developer experience than Python, Rust, or C++, but because when you move to a new framework with blockchain infrastructure, you have to use a different programming language. Solidity is good because it can be compiled efficiently to the Ethereum virtual machine. Let me give you another example. If you want to write really good graphics that take full advantage of the GPU, you should write in CUDA because it is a language that can maximize GPU performance.
It’s the same with STARK proofs. With a different virtual machine comes a different set of constraints about what makes something valid or invalid. If you want to achieve the performance that STARK proofs can achieve, such as putting one million NFTs in a block on Ethereum, you need to use the programming language more efficiently. We can mint ten million NFTs in a proof on Immutable X, and I can’t imagine any EVM-based or any zkEVM-based solution coming close to what we can fit into a single blockchain proof. I can challenge the entire world of zkEVM and they won’t be able to do it. This is why you need a different computing model and a different programming language.
BlockBeats: But many ecosystem projects that have adopted the Rust language, like Polkadot, have generally given me feedback on operating costs because it is very expensive to hire or train an engineer who knows how to develop contracts using Rust. On the other hand, if the team develops projects on Ethereum or an EVM-compatible L1, it is very cheap. How do you view this situation? Is this a problem for the Starknet ecosystem?
Eli: This may be a problem, but developers are flocking towards Cairo and STARK. The number of developers and teams is increasing every day, and I think they see the potential. Many people understand the scalability issue and ask themselves what the best and most forward-looking solution is, and what really opens up global demand for scalability. I think many of them have come to the right conclusion, which is to go down the path of Starknet and Cairo 1.0.
Here’s an analogy. Typically, you would write your software’s first version in Python, but when you want to achieve scalability, you need to write in other very efficient languages like C++, WASM, Rust, etc. I think the same thing will happen with Cairo, where you might deploy Solidity code to Kakarot, but it’s like writing a high-frequency trading engine in Python, which you shouldn’t do. You need to write in another language, which will be Cairo.
BlockBeats: There are now some projects developing zkEVMs based on Starknet.
Eli: Yes, there are very good projects building ZK-EVMs on StarNet. The first is called Warp, made by the NetherMine team, which is very good. The second is called Kakarot, which is a forming community.
Kakarot is a ZK-EVM built on Cairo. So I am very sure that most of the ZK-EVMs will be deployed on Starknet. If you already have the idea of moving your Solidity or EVM code to L2, an effective Rollup, your best bet is to do it on Kakarot or Warp. So this again shows the power of Cairo and Starknet.
ZK Rollup Competition and Starknet Ecosystem Development
BlockBeats also mentioned the competition between ZK Rollups and the development of the Starknet ecosystem in the interview. As the most technically demanding field in the entire crypto industry, it seems difficult for ordinary users to distinguish between the advantages and disadvantages of zkSync and Starknet. For most people, the actual situation is that whoever is better at “coming up with something” will be favored. From this perspective, StarkWare’s idea of driving core innovation with technology seems to have given Starknet a problem. How does Eli himself view the competition between ZK Rollups? What are his expectations for the development of the Starknet ecosystem?
BlockBeats: In the current ZK Rollup race, Starknet and zkSync are definitely leading the pack, and there seems to be strong competition between the two. In your opinion, what is the difference between Starknet and zkSync, and what are the advantages of Starknet?
Eli: You have to ask yourself, where are the best technical steps? Where is the most likely place to gather the most developers and provide the best, safest technology? We demonstrated our ability before zkSync, they are good at telling stories, but there is a big mismatch between the stories they tell and the developer experience. I have a suggestion, I encourage developers reading this article to try developing or deploying something on zkSync and then try developing and deploying something on Starknet, you will feel a distinct difference.
Let me tell you a story, someone asked on Reddit who could do something that could handle 300,000 transactions. We did it on the mainnet, with TPS at around 3,000. A week or two later, the zkSync team came out and said we have 3,000 TPS, but that 3,000 TPS has never been measured, proven or demonstrated, but it’s a good story. There are many people in this industry who are happy to tell stories, and there are those who show facts, and we are proud of our ability to show facts.
BlockBeats: There are also user feedbacks that the gas for transferring assets or interacting on ZK Rollup is currently high, why is that?
Eli: Currently, due to high demand, Starknet is congested. We will release 12 versions within two weeks, which will greatly increase TPS and solve most of the demand. Then in the next version, when we fully integrate Volition for off-chain data processing, prices will be greatly reduced, which may happen in one or two months.
BlockBeats: Regarding ecological developers, some people have indeed responded that Starknet is more balanced in terms of ecological development than zkSync.
Eli: Yes, this is the result of a better and deeper technical understanding. We have been working in this field for a long time, deploying content in production environments, and honing the system. We know what we’re doing. But we’re not good at telling stories, we don’t hype it up very often. We’re like Tesla, Tesla doesn’t have a marketing department, our product is our marketing.
StarkWare Sessions 2023 conference scene, image source: StarkWare
BlockBeats: But in the Web3 field, teams that understand marketing seem to be more popular. Many technology-driven projects have encountered problems in their ecological development, haven’t they?
Eli: No, I don’t think this is what will happen next. I think this because that’s how Ethereum developed. One day, there will be a very successful app that realizes the ability of Starknet. I don’t know what that app is now. If you ask me to guess, I think it’s not a product that currently exists on L1 and can be easily copied and pasted to L2.
So I think everyone will see and talk about it because it’s a brand new application that can’t be implemented on L1 or even other L2s. This will be a turning point, and developers will flock to it. That’s why we focus most of our attention here. We came to EDCON this time to get in touch with more developers and invite them to join our ecosystem. Because among them, someone will create something wonderful that I can’t predict.
BlockBeats: Do you have any directional suggestions for developers who are preparing to develop in the Starknet ecosystem? What can Starknet provide for them?
Eli: I can’t answer that question for them. Even if I give an answer, they shouldn’t listen to me, they should decide for themselves. I think some things are amazing. There are many truly amazing things that can be done on Starknet, such as building database infrastructure, advanced Oracle services, Proof of Humanity, social networks, etc. They should research and find out what they think is missing or what they think is the most interesting.
Starknet is the next step in the evolution of blockchain, and this is a very important step. If you are a developer, Starknet will be ready for users, and we are building it for the end user. I think we have a very clear path forward, and there are still many tools to build for more developers, and many things to do. There are many opportunities to stand out and work hard to earn a reputation for yourself.
BlockBeats: Finally, is there anything else you would like to say to our readers?
Eli: If there were a time machine, you might want to go back to the early days of Ethereum, where almost anything you wanted to build would be very successful, such as the first prediction market, the first wallet, and so on. But the game is not over yet, and there is a next-generation opportunity, and I believe the winner of this generation will be Starknet. So besides having a time machine, you can also learn about Starknet now, it’s time.