This article is the transcript of a speech delivered by Ethereum co-founder Vitalik Buterin at Shanghai Blockchain Week on October 23, 2025. In this speech, Vitalik reviewed the half-century development of cryptography, beginning with the origins of signature and encryption algorithms, and explained how cryptography has driven the evolution of blockchain technology. He focused on the breakthroughs in scalability, security, and privacy achieved by zero-knowledge proofs (ZK) and fully homomorphic encryption (FHE), demonstrating how these new technologies enable blockchain systems to be simultaneously efficient, cost-effective, and developer-friendly. The speech delved into the potential of ZK in privacy-preserving computing, hardware trusted execution, and Web3 infrastructure, and proposed a new security philosophy: "Not your silicon (hardware), not your private key." Vitalik emphasized that as the cost of ZK technology decreases and its performance improves, the future development of blockchain will shift from "why do we need ZK" to "why not use ZK." He called on developers around the world to actively participate in the construction of the ZK ecosystem, from underlying cryptographic research to decentralized application development, to jointly shape an era of trusted computing based on cryptographic verification. Vitalik: Hello everyone, welcome to this blockchain event. In the past 10 years, the blockchain and cryptography industries have developed a lot. Blockchain technology was very early in its infancy, and the value proposition of blockchain now is very different from 10 years ago. The topic of my speech today is: Thinking about the long-term future of blockchain and cryptography. If blockchain, ZK, FHE, and all these other technologies are (first) scalable, secondly developer-friendly, and thirdly inexpensive, and if these technologies don't have many drawbacks, what can we do with them? Cryptography is actually divided into many parts. The existing parts are first signatures and second encryption. Encryption is the difference between HTTP and HTTPS. You should remember that 20 years ago, there was no HTTPS. The technology existed, but no one used it. But now, 20 years later, every website, every app, and every application is built on HTTPS and signatures. The second part is signatures. Why didn't we have this 20 years ago? Why do we have it now? Because the cost of signing and encryption is now almost zero. In fact, these technologies existed in theory 50 years ago. Before 1976 and 1978, there were important papers, such as Diffie-Hellman and RSA. It can be said that they invented the first modern signature and encryption algorithms. Around the 1980s and 1990s, starting in 1989, digital signature functionality became available. PCP was introduced around 1992, and now with various new technologies, by 2015, this technology had become abundant, ubiquitous, cheap, and simple to use, so people no longer needed to worry about its shortcomings. The Significance of Zero-Knowledge Proofs (ZK) Over the past decade, I've been working on several new cryptographic technologies, including zero-knowledge proofs (ZK), fully homomorphic encryption (FHE), and a very early-stage, new technology. Currently, you can prove over 2 million hashes in one second, making this technology incredibly efficient, increasingly secure, and providing a fantastic developer experience. Fully homomorphic encryption is expected to improve tenfold between 2023 and 2025. We now also have Blobs, which help with the secure expansion of L2. We currently have six Blobs, and we plan to reach 500 within two to three years. The gas limit on L1 increased from 30 million to 45 million this year, but we plan to increase it further, perhaps by 10x or 100x. Do you think the cost of this technology has become very low, and the developer UX has improved? The blockchain as a whole is also experiencing similar progress. What are the consequences of "abundance"? If you're currently considering ZK technology, you might be asking: Why is ZK necessary? Can we avoid it? In fact, the question often arises about blockchain: Why do we need blockchain? Can we avoid the need for blockchain? When a technology is new and expensive, people may not necessarily trust it, which is normal. But five years from now, I suspect many people's attitude towards blockchain, ZK, and new technologies will be: "Why not ZK? Why not blockchain?" ZK has had a huge impact. We now have a project, a website called ethproofs.org, where you can see many ZK EVMs. They can now prove Ethereum L1 in real time. Two years ago, this was completely impossible. Two years ago, everyone thought it would take five or ten years. But now it is possible. Currently, about 50 GPUs can prove almost all Ethereum blocks in real time. This is in line with our new gas limit (block size) of 45 million instead of 30 million. So, as we expand over the long term, we can actually build a more scalable and decentralized network. This is because we don't need every node to directly verify all transactions on the blockchain. We can use ZK for most nodes, and a ZK proof can be verified in a millisecond, which is incredibly fast. Another advantage of ZK is privacy. So, this year, we can have a project slogan: "We need to consider all aspects of Ethereum privacy, including on-chain transaction privacy, off-chain transaction privacy, and various applications." We can start working on this now. Two years ago, we could only do a little bit, but now we can do much more than before. Another important issue is the relationship between cryptography, blockchain, and hardware. In the blockchain field, we have a saying: "Not your keys, not your coins." This means that if you don't control your wallet's private keys, and someone else controls them, you can't verify the security of your coins. I believe that by 2030, we'll add another saying: "Not your silicon (hardware), not your keys." This is because everything in the blockchain relies on cryptography, and cryptography relies on private keys and algorithms. Algorithms need to run in hardware, and private keys need to be stored in hardware. Therefore, if you can't trust your hardware, you can't trust anything that happens on it. I've recently discovered that this problem applies to many fields. Blockchain has digital assets and digital identities, but the IoT also has this problem. If every device has a computer inside, how can you trust it? Healthcare also faces this issue, and privacy is crucial in this field. We recently started an interesting project. If you come to DEVCON or Singapore, you might see a small device that lets you see air quality, including CO2 levels, AQI, and many other indicators. This device will allow us to better understand what's happening in the air, which will be crucial in the future of healthcare. However, it also raises significant privacy issues. In ten or twenty years, the amount of information we know about the physical world may be 1,000 times greater than it is today. How can we protect privacy? How can we ensure security? So, we're currently developing a future version of this device, incorporating cryptographic technology. This will allow us to simultaneously determine what we want to know about the data without exposing the privacy of everyone, everywhere. ZK is very useful, as is SAT (Boolean Satisfiability Problem). First, we know cryptography is important, and we're now proving that it can actually be used. Second, open source and verifiable hardware are also crucial. In fact, the blockchain sector faces the same challenges as many other fields. How can you participate in the ZK ecosystem? All the areas I just mentioned are experiencing significant growth. How can you participate? I believe there are three answers: First, start a business. You can develop or support applications that use ZK, FHE, and blockchain technologies like ZKID. Second, research and develop and optimize underlying cryptographic technologies. We have a Lean team within the Ethereum Foundation, and there are many opportunities for collaboration. They're also available on ethproofs.org, so you can contact the Ethereum team. Thirdly, you can use existing applications based on these technologies, such as Scroll, Taiko, Lighter (a high-frequency DEX), Intmax, Aztec, and others. There are also ZK voting applications, such as ZKPassport, which has been around for about two years. There's also Aragon, which announced earlier this year that it would use ZK voting, as well as several wallets. There are already many ways to participate in these areas. I think the question we should be thinking about five or ten years from now is that many current technologies, like HTTPS and Signal, use simple cryptography like signing and encryption, but you don't know they exist. These technologies are incredibly cheap and can be used directly without having to worry about cost or user experience. If ZK and fast blockchains like L1, L2, and FHE can achieve this level of efficiency, then everything will use ZK. If so, what can be done with this technology? The answer is not simple. We need to start experimenting now, and with each passing year, we can develop more and more applications. We'll probably learn a little more about this answer. I'm very happy to be participating in this technological development process with everyone, and I hope to continue doing so for the next 10 years.
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