Exclusive Interview with the Founder of Starknet: Looking Up at the Stars, Keeping Our Feet on the Ground

Interview with Founder of Starknet: Balancing Dreams and Reality

Computer scientist Eli Ben-Sasson, creator of zk-STARK, revealed his views on STARKs, SNARKs, and the Rollup track, as well as his expectations for the Starknet ecosystem.

Interviewee: Eli Ben-Sasson, co-founder of StarkWare

Author: Jack

At the recent Ethereum EDCON conference in Montenegro, ZK became the hottest topic. From the 19th to the 23rd, whether it was individual speeches or roundtable discussions, the guests’ topics were mostly centered around vocabulary such as ZK Rollup, zkEVM, and ZKML. In the eyes of the “Ethereum core circle”, ZK has become the ultimate new narrative that can leverage the next round of industry outbreaks, comparable to the 2019 DeFi innovation.

For a long time, technical implementation has been the main challenge facing ZK, which has also made it a “future solution” in the minds of most people. However, this year, when the Arbitrum ecosystem has not yet heated up, ZK Rollups, as a technical alternative, have knocked on the door. The most obvious feeling this year is that there are suddenly more “ZK projects” of all kinds. Developers start to FOMO ZK technology, ZK transfer, ZK identity, and ZK board games. As long as it is related to privacy, the project name will definitely have the word “ZK”. This prosperous scene is of course due to the concentrated efforts of ZK Rollups such as Starknet and zkSync, as well as projects such as Scroll and Polygon.

Behind these mainstays is a big man from Israel named Eli Ben-Sasson.

Eli (@EliBenSasson) was one of the first researchers to combine ZK technology with encryption technology. He is the founder of Zcash and StarkWare and the creator of zk-STARK. The latter technology standard is the important technical cornerstone of today’s Starknet and the entire encrypted ZK track. During the EDCON conference, BlockBeats met this legendary figure. In a conversation that lasted nearly an hour, Eli showed strong technical confidence. He revealed his views on STARKs, SNARKs, and the Rollup track, as well as his expectations for the Starknet ecosystem.

About optimistic fraud proof, zk-STARK and SNARK

Many people know Eli as the co-founder of StarkWare, but few know that he is also the creator of the zk-STARK critical technology standard. Even before Ethereum, Eli began combining ZK technology to solve blockchain scalability issues and had in-depth discussions with Vitalik, who was still an author for Bitcoin Magazine at the time. StarkWare was also one of the few projects that Vitalik participated in investing in.

Eli Ben-Sasson speaks at StarkWare Sessions 2023, image source: StarkWare

As a technology-driven entrepreneur, Eli has absolute confidence in ZK technology and its underlying mathematical principles. 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 our readers why you entered the cryptocurrency field, and why you founded Zcash and StarkWare?

Eli: I was a computer science professor doing theoretical computer science research. People in mainland China may have heard of Andrew Yao, a major promoter of theoretical computer science, a Turing Award winner, and the inventor of secure multiparty computation. I entered this field many years after him.

In 2008, I started doing research related to zero-knowledge proofs (ZKPs). In May 2013, ten years ago, I attended the Bitcoin conference held 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 the proof 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 yet the founder of Ethereum, but a content author for Bitcoin Magazine. We discussed a lot of issues related to proof, validity proof, and zero-knowledge proof.

One of my early joint papers was called “Zerocash: Decentralized Anonymous Blockingyments from Bitcoin”, which talked about how to use zero-knowledge proof to protect payments on Bitcoin. This later became the Zcash project, and we have been developing this technology ever since. In 2018, we proposed better technological 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. Today, our validity proof is widely regarded as the best way to scale Ethereum.

BlockBeats: You mentioned that you had contact with Vitalik very early on, and I remember he started investing in and supporting StarkWare very early on.

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 that.

I remember Vitalik became a core investor around the fall of 2018. I attended a meeting with him, which was apparently organized by Tsinghua University, but it was definitely in Shenzhen. I remember we were walking around a very nice seafood market, discussing things like StarkWare, his investments, and a lot of other things. So the details of this decision were made in China.

BlockBeats: You started considering using ZK proofs as a scaling solution before Ethereum. How did you see that blockchain would inevitably have a scalability problem?

Eli: I believe readers in the Chinese community must be familiar with Alipay and WeChat Pay. Their transaction speed may have reached one million transactions per second. Now, blockchain needs to do NFT, games, voting, elections, and governance. In order to make all of these happen, the current technology is not good enough. On Bitcoin and Ethereum, there are probably 10 to 20 transactions per second. This requires other technologies, some technologies that do not compromise the security of the blockchain, but expand the scope or reach of the blockchain, and that’s what Starknet does.

BlockBeats: Arbitrum founder Professor Ed Felten also started solving the scalability problem around 2014, but he decisively chose Interactive Fraud Proof, which was later widely regarded as a 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 Ethereum core team, everyone knows that Optimistic Rollups did not turn on their core technology. Neither Arbitrum nor Optimistic has fraud proof. The reason they didn’t turn it on is because 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 because it doesn’t work, it hasn’t been turned on. There is a big difference between something that should but doesn’t work, and something that does work and can be proven.

BlockBeats: But although Vitalik invested in StarkWare, he then supported Optimism. There seems to be an increasing consensus in the crypto space that scalability issues should start with Optimistic and then move to ZK, because ZKP or ZK Rollup is much harder 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 don’t we put feathers on people and make them flap their wings to build airplanes? It’s more meaningful, which is why Leonardo da Vinci drew people with wings. But it doesn’t work mathematically or economically. I really appreciate and admire their intelligence and truly great community members, but it doesn’t change the fact that it’s a technology that can’t work well.

BlockBeats: But as an ordinary user, Optimism and Arbitrum are indeed practical solutions for the time being.

Eli: Of course, but what needs to be realized is that your asset security is based on trusting a single operator, and then it works very effectively. Here’s another possibility that works very well. You can bridge your assets to any computer that you trust very much. It can be a centralized exchange or anything similar, and then you get amazing TPS throughput, but you are entrusting all of your funds to that computer controlled by that person. If it fails, goes offline, or acts maliciously, all of your funds will disappear.

Arbitrum, Optimism, and Binance have the same security assumptions, and Binance is a good product for users, perhaps even better than Arbitrum, but it’s important for users not to be fooled into thinking that they have a higher level of security when transferring assets. If someone says I won’t use Binance because it’s controlled by a centralized process, I want to go decentralized, I want to put my assets on Arbitrum or Optimism, 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 wasn’t designed to be operated by a single operator from the beginning. So I think it gives you less legal protection than Binance.

BlockBeats: Speaking of ZKP, you have created zk-STARK in addition to the widely recognized zk-SNARK. Why set two different technical standards for ZK technology? And why did StarkWare ultimately choose zk-STARK?

Eli: With SNARKs technology, Groth-16 type pre-processing SNARKs, which uses elliptic curves, it can be ready for production earlier, but I think it is a relatively inferior technology in terms of efficiency and security. It’s like there is a technology that is not so good, but it appears first, like the steam engine is not as good as the gasoline engine, but it appears first, which is somewhat similar to this situation.

As for why choose zk-STARK, it is a choice that requires no thought. It has the most secure and future-proof basic technology, relying on battle-tested mathematics and encryption technology. It is worth mentioning that it is post-quantum secure, which other systems cannot achieve. It has the fastest and most efficient proofs, which makes it the highest level of all proof technologies.

Comparison of zk-STARK and zk-SNARK technology details, image source: Horizon Academy

BlockBeats: Many current ZK Rollup and zkEVM projects use zk-SNARK. What is your view on the future of zk-SNARK?

Eli: I think it will gradually be phased out. It may remain for personal shielded transactions, in which case users may not care about the inefficiency of proof time. And there are indeed very short proofs, about 200 bytes or so. So they may have some use in the privacy field, for personal shielded transactions, but once they reach larger throughput, this is the only way. All blockchain validity proof projects with the largest number of transactions are now using STARKs, from Hermez, Miden to Polygon Zero, and so on. Some projects are currently using SNARKs temporarily, but will eventually switch to STARKs. So now the largest number of blockchain validity proof projects are using STARKs.

About Starknet, Cairo, and zkEVM

What is difficult for many people to understand is that as an Ethereum L2, Starknet itself is not compatible with the Ethereum EVM, and developers need to use the new Cairo language for contract development. This seems to have deprived Starknet of many advantages of EVM-compatible L1 and Ethereum-equivalent L2, that is, to minimize development costs and to quickly launch the ecosystem in a short period of time. But in Eli’s view, these issues become less important in the face of the huge potential brought by Cairo. More importantly, the Starknet ecosystem already has its own solution to this.

BlockBeats: Why did StarkWare create two separate projects, StarkEx and Starknet? Why not combine them?

Eli: StarkEx and Starknet serve two different purposes. When you’re talking about a very specific kind of high-throughput transaction, like minting and trading NFTs, then you can get better performance and throughput from a system that’s built specifically for that purpose, which is StarkEx. We started with a very specific use case and tested the entire technology in the field, and we’re very proud of that.

Starknet, on the other hand, is a more complex build, so it naturally came later, and it serves a different purpose, allowing you to do general computation, like Ethereum, but that general computation means that its performance won’t be as good as the specific performance for a specific use case. So, it’s a trade-off between generality and efficiency.

BlockBeats: So achieving high transaction TPS in specific applications is very important for the StarkWare team?

Eli: Yes, it’s very important for us to achieve that goal. Many teams “run their own projects on Twitter” and release some nice numbers, hoping that people will be fooled into thinking that it’s an effective system. But we’re proud of our high TPS system that has been running for years. It’s all about improving throughput and lowering transaction costs.

What I want to say is that so far, our system has processed nearly $1 trillion in transactions, over 450 million transactions, and issued over 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 achieve this level, and we’ve never used more than 1% of Ethereum Gas, even when our TPS has 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 of its business model from the beginning.

Eli: I often like to say “look up at the stars, but keep your feet on the ground.” We are very knowledgeable about math, engineering, and technology, and are easily 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 content that can’t meet users’ immediate needs, and instead we focus very hard on providing users and clients with what they really need. As a scientist, the whole team knows that I am very sorry that I can’t do things like elliptic curve fast Fourier transform (ECFFT), and many other strange technologies that we know can improve performance by 10 or even 100 times.

BlockBeats: Next, I’d like to talk about the Cairo language. As an Ethereum L2, Starknet is not compatible with Ethereum EVM, so developers must use the Cairo language to build applications. This seems to have lost many of the advantages of the “EVM compatible ecology” for Starknet. Why choose to build your own language?

Eli: Yes, I’d like to say a few things about Cairo. First, it is an advanced, next-generation smart contract programming language. It supports some new features from the beginning, such as smart wallets, or account abstractions, which are built into the Cairo language. It is a Rust-inspired programming language, and many developers who try Solidity and use it, especially those who know Rust, will say they prefer to program with Cairo rather than Solidity. So it’s a very, very good programming language in and of itself.

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 very similar to the reason for wanting to write smart contracts in Solidity. You need to use Solidity not because it has a better developer experience than Python, Rust, or C++, for example. On the contrary, its developer experience is worse, but when you move to a new framework with a blockchain infrastructure, you have to use a different programming language, and Solidity is good because it can be compiled efficiently into the Ethereum virtual machine. Here’s another example. If you want to write really good graphics using a GPU, you should write it in CUDA, because that is a language that can take full advantage of GPU performance.

It’s the same with STARK proof. With a different virtual machine, there is a different set of constraints about what makes something valid or invalid. If you want to achieve the performance that STARK proof can achieve, such as putting a million NFTs in a single block on Ethereum, you have 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 approach coming close to what we can put in a single blockchain proof. I can challenge zkEVM all over the world, and they won’t be able to do it. That’s why you need a different computational model and a different programming language.

BlockBeats: Many eco-projects that use Rust language, such as Polkadot, have generally given me feedback on the issue of operating costs, because the cost of hiring or training an engineer who knows how to develop contracts with Rust language is very high. On the other hand, if the team develops projects on Ethereum or L1 compatible with EVM, it is very cheap. What do you think of this situation? Is this a problem for the Starknet ecosystem?

Eli: This may be a problem, but developers are rushing to Cairo and STARK. The number of developers and teams is increasing every day, and I think they see the potential. Many people understand the problem of scalability and ask themselves what is the best and most forward-looking solution, and what truly opens up the scalability of global demand. I think many of them have come to the right conclusion, which is to take the road of Starknet and Cairo 1.0.

Here’s an analogy. Usually you write the first version of your software with Python, but when you want to implement scalability, you need to write with other very efficient languages such as C++, WASM, Rust, etc. I think the same thing will happen in Cairo. You may deploy Solidity code to Kakarot, but it’s like writing a high-frequency trading engine with Python, which is not appropriate. You need to write with another language, which will be Cairo.

BlockBeats: There are now some projects developing zkEVM based on Starknet.

Eli: Yes, there are very good projects building ZK-EVMs on StarNet. The first one is called Warp, made by the NetherMine team, which is excellent. The second one is called Kakarot, which is a forming community.

Kakarot is a ZK-EVM built on Cairo. So I am very sure that most ZK-EVMs will be deployed on Starknet. If you already have the idea of porting your Solidity code or EVM code to L2, an effective Rollup, your best way is to do it on Kakarot or Warp. So this again demonstrates 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 itself in the interview. As the most technically demanding field in the entire encryption industry, ordinary users seem to have a hard time distinguishing the advantages and disadvantages between zkSync and Starknet. For most people, the actual situation is who is better at “doing things”. From this perspective, StarkWare’s core driving concept of technological innovation seems to have posed a challenge to Starknet. 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 absolute leaders, 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 abilities 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 try developing and deploying something on Starknet, you will feel a distinct difference.

Let me tell you a story, someone on Reddit asked who could do something that can perform 300,000 transactions, and we did it on the mainnet, with TPS of about 3000. A week or two later, the zkSync team came out and said, we have 3000TPS, but this 3000TPS has never been measured, proven, or demonstrated, but it is a good story. There are many people in this industry who are willing to tell stories, and there are people who show facts. We are proud of our ability to show facts.

BlockBeats: There is also feedback from users that the gas for asset transfer or interaction on ZK Rollup is currently high, why is this?

Eli: Currently, due to high demand, there is congestion on Starknet. 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, the price will be greatly reduced, which may happen in one or two months.

BlockBeats: Speaking of ecosystem developers, some people do react that Starknet is more balanced than zkSync in terms of ecological development.

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 systems. We know what we are doing. But we are not good at telling stories and rarely hype up. We are like Tesla, Tesla has no marketing department, our product is our marketing.

Live scene of StarkWare Sessions 2023, sourced from StarkWare

BlockBeats: But in the Web3 field, teams that understand marketing seem to be more popular. Many technology-driven projects have encountered problems in ecological development, don’t they?

Eli: No, I don’t think that’s going to happen next. I think that because that’s how Ethereum developed. One day, there will be a very successful app that understands the capabilities of StarkNet. What that app is, I don’t know now. If I had to guess, I don’t think it’s a product that currently exists on L1 and can be easily copied and pasted to L2.

So I think it will be something that everyone will see and talk about because it’s a completely 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’re focusing most of our attention here. We came to EDCON this time to reach out to more developers and invite them to join our ecosystem. Because among them, there will be someone who creates something wonderful that I can’t predict.

BlockBeats: Do you have any directional advice for developers who are preparing to develop on the StarkNet ecosystem? What can StarkNet offer 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, building database infrastructure on StarkNet, like advanced Oracle services, Proof of Humanity, social networks, and so on. There are many truly amazing things to do, and they should research and find out what they think is missing, or what they think is the most interesting thing.

StarkNet is the next step in the evolution of blockchain, and this is a very important step. If you’re a developer, StarkNet will be ready for users to use, and we’re building it for end users. I think we have a very clear path forward, and there are still many tools to be built and many things to be done for more developers. There are many opportunities for you to stand out and work hard to win your own reputation.

BlockBeats: Finally, do you have anything else you’d like to say to readers?

Eli : If there were a time machine, you might want to go back to the early days of Ethereum and build almost anything you wanted and be very successful, such as the first prediction market or the first wallet. But the game is not over, there is another opportunity for the next generation, and I think the winners of this generation will be Starknet. So now, besides having a time machine, you can go and learn about Starknet, it’s time.