Written by: Sanqing, Foresight News
With the surge in the privacy sector prices, the “privacy narrative” has once again returned to the market's view. Funds are looking for targets labeled “privacy” on charts, and the community is discussing whether “privacy will become the next main theme.” However, if the perspective only stays on the market fluctuations of a particular privacy public chain or a single cryptocurrency, it is easy to miss a more critical turning point. At the 2025 Ethereum Argentina Developer Conference, Ethereum founder Vitalik Buterin, in a roughly thirty-minute roadmap speech, once again placed privacy within the future technological and governance framework of Ethereum.
What does “privacy” really refer to?
In daily life, when talking about privacy, it mostly refers to “don't let others casually view my chat records, salary, address.” On public chains like Ethereum, the situation is exactly the opposite, with the default setting being: as long as it's on the chain, it is public to everyone.
Everyday privacy and privacy in the context of Ethereum are like two branches on the same tree, with the latter being broken down into finer and more technical details. Discussing privacy in the context of blockchain primarily involves handling several very specific types of information.
The first is the assets and transaction records. What addresses do you have, what assets are there at each address, how much money has been transferred between these addresses, and how frequently, all of this is clear on the blockchain. Anyone can see it by opening a blockchain explorer.
Secondly, identity and relationships. A single address appears to be a random string, but through transaction relationships and temporal patterns, analysts can often infer which addresses belong to the same user, which addresses interact with the same group of counterparties over a long period, thereby piecing together your “on-chain social circle” and funding paths.
Thirdly, behavior trajectory and preferences. What time periods you prefer to interact, which protocols you commonly use, whether you favor high-risk products, and which new launches or airdrops you frequently participate in, all contribute to a “behavioral resume.” Who can use this resume and for what purpose is a practical question.
Fourth is the network and device information. When wallets, browsers, and RPC services are in operation, they may encounter your IP address, rough geographical location, and device fingerprint. If this is further linked to an on-chain address, the data is no longer just an “anonymous address” but rather a clue to your identity gradually converging with the real world.
From “Don't be evil” to “Can't be evil”
In his speech at this conference, Vitalik once again summarized Ethereum's goals using a familiar analogy. He mentioned that centralized exchanges like FTX operate on the principle of “everyone trusts a certain person or company,” but the ledger and risk exposure are not visible to the outside world. A slogan commonly used by early internet giants was “Don't be evil,” meaning the company promises not to do harm.
The goal of blockchain is different. What Ethereum hopes to achieve is “Can't be evil,” designing the system through cryptography and consensus mechanisms so that even if individual participants have malicious intentions, it is difficult for them to succeed.
In this framework, “transparency” addresses issues from the first half. Public ledgers and verifiable states can prevent assets from being misappropriated without anyone knowing, which is one of the repeatedly emphasized values of blockchain. However, if all information is pushed towards extreme transparency, another type of risk will arise: in the hands of a party that possesses all behavioral data and has the analytical capability, this data could transform into an overwhelming intelligence advantage, used for profiling, stratification, differential treatment, and even creating new centers of power in terms of scrutiny and regulation.
Therefore, the true meaning of “do no evil” must be limited at both ends. One end is that assets and states cannot be quietly rewritten; the other end is that information and permissions cannot be infinitely concentrated in the hands of a few subjects. Privacy is the key tool for the latter. It is not opposed to transparency, but rather adds boundaries to transparency: the part that must be public should be made public, while the remaining information is controlled within the limits of “minimum necessary disclosure.”
Vitalik: Privacy is Ethereum's shortcoming.
Vitalik explicitly listed privacy as something that is not suitable for blockchain when outlining what blockchain is “suitable for and not suitable for.”
In his view, the advantages of Ethereum are very clear. For example, payments and financial applications, DAOs and governance, ENS and decentralized identity, censorship-resistant content publishing, and the ability to prove that something actually happened at a certain point in time or has scarcity.
At the same time, the shortcomings are also clear: a lack of privacy, difficulty in supporting extremely high throughput and extremely low latency computing, and an inability to directly perceive information from the real world, etc. The privacy issue is not an experience defect of individual DApps, but rather a limitation explicitly stated at the current architectural level.
This means that in the narrative of the official Ethereum roadmap, privacy is no longer just a high-end feature piled on top, but one of the inherent known flaws of this architecture. The way to solve this problem is not as simple as just adding a privacy sidechain. What Vitalik describes is another path. By using a more diverse combination of cryptographic tools and protocols, privacy is abstracted into a foundational capability.
In the speech, the components mentioned such as Swarm and Waku serve the roles of decentralized storage and messaging, respectively, combined with modules of “programmable cryptography” like zero-knowledge proofs and homomorphic encryption. These pieces are not meant to serve an isolated project but rather act as a toolbox for all developers. The goal is to leave space for more refined privacy design without sacrificing the public settlement attributes of the mainnet.
It can be summarized as: the future Ethereum is more of a combination of “transparent settlement layer + programmable privacy layer,” rather than simply oscillating between complete transparency and complete black box.
LeanEthereum: Laying the Foundation for “Provably Hidden”
In a longer-term plan, Vitalik proposed the concept of “Lean Ethereum”, hoping to adjust the various components of Ethereum to a more compact and theoretically optimal form through a series of replacements and simplifications, with many aspects directly related to privacy.
One is the virtual machine and hash function that are friendly to zero-knowledge proofs. Currently, deploying complex ZK systems on Ethereum is costly and has a high barrier to entry. One important reason is that the underlying virtual machine and state structure were not designed with “proof-friendly” as a prerequisite, somewhat akin to running a heavy-duty truck on a regular road. Lean Ethereum attempts to make the capability of “proving something is legitimate without exposing all the details” a cost-controlled routine operation by adjusting basic elements such as the instruction set, state data structure, and hash algorithm, rather than an expensive privilege that only a few protocols can afford to bear.
The second point is post-quantum cryptography and formal verification. Once a privacy system is compromised, it is often difficult to “remedy” it afterwards. For example, if a widely adopted encryption scheme is broken by quantum computing in the future, historical data may collectively lose protection in a short period of time. Ethereum has proactively considered quantum threats in its long-term roadmap and promotes formal verification of key components, essentially reserving security boundaries for future privacy contracts, privacy rollups, and privacy infrastructure.
User-side privacy: blind signing is both a security issue and a privacy issue.
Outside of the protocol layer and the architecture layer, another focus that the Ethereum Foundation continuously emphasizes in this roadmap and related agenda is user experience and security. This aspect is highly related to privacy as well.
In the Trillion Dollar Security presentation, the foundation's security team directly referred to the current widespread phenomenon of “blind signing” as a “plague”. When users initiate an operation in their wallet, a signature window pops up, displaying a long string of incomprehensible hexadecimal data along with a contract address. Users find it difficult to determine what permissions this signature will grant and what information it may expose, but if they wish to complete the operation, they ultimately have no choice but to press “Confirm”. This situation simultaneously triggers two landmines: security and privacy.
On the security front, users may unknowingly grant the permission to “withdraw all assets at any time” to an unknown contract during what seems to be a regular interaction. On the privacy front, users are unaware of what behavioral data will be exposed by this signature, do not know which party is collecting, storing, and analyzing this data, and have no way of knowing whether this data will be used for profiling, risk control, or even targeted phishing. For users, this is like handing over a pass token in a black box; for the side that controls the infrastructure, the related actions are extremely transparent.
Such issues are difficult to completely alleviate through “simply raising security awareness.” A more realistic approach is to promote transformation from the standards and product level. For example, by unifying wallet specifications and contract interfaces, the consequences of transactions can be presented in a human-readable manner; more complex data exchanges should be encapsulated in proofs or encrypted channels, rather than requiring users to directly expose details. Additionally, with the evolution of light clients, account abstraction, network and RPC layer privacy protection, on-chain interactions may still maintain auditability and accountability under the premise of “not completely exposing oneself.”
Beyond the market: The focus of privacy narratives is shifting.
From a market perspective, the phased increase in privacy-related assets indicates that the label of “privacy” still possesses sufficient narrative tension. However, compared to the previous cycle, the focus in the privacy track is slowly shifting from “betting on a certain privacy chain” to “betting on who is solidly building privacy infrastructure.”
On one end, there are dedicated privacy networks and privacy assets centered around technologies like zero-knowledge proofs, continuing the path of “hiding transaction details on-chain as much as possible”; on the other end, there is a complete set of infrastructure and toolsets built around privacy within the Ethereum ecosystem, including ZKRollup, privacy middleware, privacy-friendly wallets, and more secure contract interaction frontends.
In Vitalik's roadmap, Ethereum does not attempt to turn everything into an “untraceable black box,” but rather emphasizes “controlled transparency” and “minimum necessary disclosure.” The settlement layer remains public, with the verification logic guaranteed by cryptography and contracts, while specific business data is protected in layers according to different scenarios through zero-knowledge proofs, encrypted communication, and access control.
