Many people don't understand why @VitalikButerin promoted Kohaku and donated 256 ETH. If you think it's just a charitable donation, you're sorely mistaken: it involves the evolutionary logic of three models: "absolute privacy," "optional privacy," and "privacy equals security." Let's discuss it:
1) Absolute Privacy Mode
"Absolute privacy" is a feature that Tornado Cash, Railgun, Aztec, and Monero originally had. The core logic is to create a completely black-box "privacy pool". Once funds are deposited, all transaction information, including sender, receiver, and amount, is encrypted and cannot be seen by the outside world, including regulators!
This means that if illicit funds and legitimate funds are mixed together and pass through this privacy channel, the privacy tool will become a money laundering tool and will therefore be subject to regulatory sanctions. So at present, the absolute privacy solution can only remain at the tool service level. To expand, it is necessary to explore solutions that embrace regulation.
2) Optional privacy mode
"Optional privacy" is a compromise solution that @Zcash has been exploring recently with its dual-track system of transparent and masked addresses. The core logic is to allow users to actively choose: either use a fully masked address, which can be compared to absolute privacy, or use a transparent address to meet the needs of regulators.
This is certainly a step forward, as it adds an extra layer of intent to the tool. If the subject is an individual, they can choose absolute privacy; if the subject is an institution that embraces regulation and has an audit process, they will naturally choose optional privacy.
However, it is not easy to promote such solutions, because using a blocked address is tantamount to putting up a label of "protesting too much" when there is optional transparent privacy. It stigmatizes privacy and makes it a privilege of a very small number of people, rather than a standard feature for the general public.
3) Privacy as Security Mode
Vitalik and the Ethereum Foundation's series of actions all have one purpose: to upgrade optional privacy to a standard feature of "privacy is security." This is what V has always emphasized: Privacy is not a feature, it's a prerequisite for security!
This concept presents a challenge: how to ensure privacy while avoiding regulatory scrutiny? In other words, default privacy + optional disclosure = decentralized privacy protection and compliance with regulatory requirements.
Therefore, Kohaku's design follows a path combining Stealth cryptography, elliptic curve cryptography, and ZK proofs, among other technical solutions, to achieve a balance between privacy protection and optional disclosure. Kohaku is more like a modular privacy embedding layer that can directly serve wallets, popularizing privacy through application-layer habit migration.
But that's not enough. Vitalik is well aware that the major challenge to the privacy narrative lies in the "off-chain environment." On-chain technologies like decentralized verification infrastructure and ZK and FHE are used to achieve a balance, but in the off-chain environment, protecting user metadata privacy and the decentralized message transmission layer become bottlenecks.
Therefore, the donations to @session_app and @SimpleXChat were made to explore how to achieve end-to-end encrypted communication in a decentralized environment, thereby completing the entire privacy pipeline of on-chain + off-chain.
The ability to register without a phone number using Session, coupled with SimpleX's ability to remove even the ID, reinforces the fact that privacy (off-chain: IP address, communication objects, etc.; on-chain: transaction links, interaction details, etc.) is part of the underlying security framework.
Therefore, following Vitalik's directive approach, the privacy track can provide a platform for many technical projects to leverage his expertise, including the general-purpose ZK aggregation verification layer @boundless_xyz, the embeddable intent-based privacy transaction layer @anoma, and the cryptographic holy grail-level FHE solution @zama, among others.
