1. The Last-Mile Problem Vitalik Finally Fixed
On stage in Buenos Aires, Vitalik Buterin opened with a confession: Ethereum has world-class cryptography, a battle-tested L1, and more zk papers than most countries have roads—yet using it still feels like doing your taxes in a command-line terminal.

Kohaku—Japanese for “amber,” the stuff that traps and preserves—is the Foundation’s answer. It is not another mixer, not another L2, but a wallet-level privacy toolkit: a Lego box of modular SDKs and a reference browser-extension wallet (built on Ambire) that turns discretionary privacy into a default setting.

2. Inside the Kohaku Wallet: Multi-Key, Risk-Rated, IP-Invisible

• Multi-key architecture – everyday spending key, vault key, recovery key; no single mnemonic to rule them all.

• Risk-based approvals – $10 goes through instantly, $100 k forces a second factor and a 24-hour delay.

• Plug-and-play privacy – transactions can be routed through Railgun or Privacy Pools without leaving the wallet; no new trusted setup required.

• Network cloaking – native integration with mixnets (NYM) and soon zk-RPC so that even balance lookups never expose the user’s IP.

The goal is to make “private” the default radio-button instead of a hidden advanced tab.

3. Why This Matters: A Shared Infrastructure Instead of 1 000 Re-inventions
Until now, every rollup team had to reinvent stealth addresses, recovery flows and compliance hooks. Kohaku offers a common library—think of it as ERC-4337 but for privacy. If adopted, wallets can stop competing on who builds the best anonymity stack and start competing on UX, fiat on-ramps and cute fox logos.

It also drags Ethereum into the regulatory daylight. Association lists and view-keys are baked in, letting issuers prove “we are not laundering” without revealing the world’s balances. Whether that is the perfect balance or a slippery slope is now a live, testable debate rather than a Twitter flame-war.

4. The Privacy Arcade: Nine Projects That Filled the Hall
While Kohaku stole the keynote, the adjacent “Privacy Zone” felt like a sci-fi bazaar. The heavy-hitters:

• Aztec – zkRollup with programmable private state; public testnet live, Noir language shipping.

• Railgun – DAO-governed privacy pool across Ethereum, Arbitrum, Polygon; “Private Proof-of-Innocence” exports view-keys for auditors.

• 0xbow – Privacy Pools with an Association-Set Provider that screens deposits against sanctioned addresses in zero-knowledge.

• Fileverse – end-to-end-encrypted Google-Docs-on-IPFS; access rights handled by UCAN tokens.

• Holonym – “Human.tech” stack: prove you’re over 18, a citizen, or not a bot without doxxing yourself.

• Fluidkey – generates a fresh stealth address for every incoming payment; $400 M TVL already routed through it.

• Rarimo – zk-passport + unlinkable social-recovery wallet (Unforgettable); vote anonymously on Snapshot.

• ZKPassport – standalone protocol turning government NFC chips into zk proofs of nationality or age.

• NYM – mixnet that anonymises packet metadata, already plugged into Kohaku’s roadmap.

5. Institutional Reality Check: Privacy as a Prerequisite, Not a Feature
Danny Ryan (ex-EF researcher) put it bluntly: “Pension funds don’t care about your ape JPEGs. They care that their portfolio allocations can’t be front-run. No privacy, no mandate, no inflow.”

Coin Center’s Val Keenburgh framed the stakes even sharper: “Anything transparent is eventually captured; anything captured ceases to be neutral.” For Wall Street, privacy is not ideology—it is a fiduciary duty.

6. The Philosophical Pivot: Freedom, Order, Progress
Vitalik’s April essay “In Defence of Privacy” argued that privacy is the triad that keeps society alive:

• Freedom – room to experiment without eternal social scoring.

• Order – markets and democracies need non-public negotiations to function.

• Progress – medical research, AI datasets and credit scoring all require selective disclosure, not glass-house transparency.

Buenos Aires turned that essay into working code.

7. What Happens Next
Kohaku’s reference wallet ships in Q1 2026; the SDK is already on GitHub under Apache-2.0. Major teams—MetaMask, Rabby, Keystone—have commits in the repo. If the merge-into-existing-privacy-tools strategy wins, Ethereum will have done for private payments what ERC-20 did for tokens: make them boring, standard and everywhere.

The amber has hardened. Now we watch who gets trapped inside—and who walks out free.

1. The Last-Mile Problem Vitalik Finally Fixed
On stage in Buenos Aires, Vitalik Buterin opened with a confession: Ethereum has world-class cryptography, a battle-tested L1, and more zk papers than most countries have roads—yet using it still feels like doing your taxes in a command-line terminal.

Kohaku—Japanese for “amber,” the stuff that traps and preserves—is the Foundation’s answer. It is not another mixer, not another L2, but a wallet-level privacy toolkit: a Lego box of modular SDKs and a reference browser-extension wallet (built on Ambire) that turns discretionary privacy into a default setting.

2. Inside the Kohaku Wallet: Multi-Key, Risk-Rated, IP-Invisible

• Multi-key architecture – everyday spending key, vault key, recovery key; no single mnemonic to rule them all.

• Risk-based approvals – $10 goes through instantly, $100 k forces a second factor and a 24-hour delay.

• Plug-and-play privacy – transactions can be routed through Railgun or Privacy Pools without leaving the wallet; no new trusted setup required.

• Network cloaking – native integration with mixnets (NYM) and soon zk-RPC so that even balance lookups never expose the user’s IP.

The goal is to make “private” the default radio-button instead of a hidden advanced tab.

3. Why This Matters: A Shared Infrastructure Instead of 1 000 Re-inventions
Until now, every rollup team had to reinvent stealth addresses, recovery flows and compliance hooks. Kohaku offers a common library—think of it as ERC-4337 but for privacy. If adopted, wallets can stop competing on who builds the best anonymity stack and start competing on UX, fiat on-ramps and cute fox logos.

It also drags Ethereum into the regulatory daylight. Association lists and view-keys are baked in, letting issuers prove “we are not laundering” without revealing the world’s balances. Whether that is the perfect balance or a slippery slope is now a live, testable debate rather than a Twitter flame-war.

4. The Privacy Arcade: Nine Projects That Filled the Hall
While Kohaku stole the keynote, the adjacent “Privacy Zone” felt like a sci-fi bazaar. The heavy-hitters:

• Aztec – zkRollup with programmable private state; public testnet live, Noir language shipping.

• Railgun – DAO-governed privacy pool across Ethereum, Arbitrum, Polygon; “Private Proof-of-Innocence” exports view-keys for auditors.

• 0xbow – Privacy Pools with an Association-Set Provider that screens deposits against sanctioned addresses in zero-knowledge.

• Fileverse – end-to-end-encrypted Google-Docs-on-IPFS; access rights handled by UCAN tokens.

• Holonym – “Human.tech” stack: prove you’re over 18, a citizen, or not a bot without doxxing yourself.

• Fluidkey – generates a fresh stealth address for every incoming payment; $400 M TVL already routed through it.

• Rarimo – zk-passport + unlinkable social-recovery wallet (Unforgettable); vote anonymously on Snapshot.

• ZKPassport – standalone protocol turning government NFC chips into zk proofs of nationality or age.

• NYM – mixnet that anonymises packet metadata, already plugged into Kohaku’s roadmap.

5. Institutional Reality Check: Privacy as a Prerequisite, Not a Feature
Danny Ryan (ex-EF researcher) put it bluntly: “Pension funds don’t care about your ape JPEGs. They care that their portfolio allocations can’t be front-run. No privacy, no mandate, no inflow.”

Coin Center’s Val Keenburgh framed the stakes even sharper: “Anything transparent is eventually captured; anything captured ceases to be neutral.” For Wall Street, privacy is not ideology—it is a fiduciary duty.

6. The Philosophical Pivot: Freedom, Order, Progress
Vitalik’s April essay “In Defence of Privacy” argued that privacy is the triad that keeps society alive:

• Freedom – room to experiment without eternal social scoring.

• Order – markets and democracies need non-public negotiations to function.

• Progress – medical research, AI datasets and credit scoring all require selective disclosure, not glass-house transparency.

Buenos Aires turned that essay into working code.

7. What Happens Next
Kohaku’s reference wallet ships in Q1 2026; the SDK is already on GitHub under Apache-2.0. Major teams—MetaMask, Rabby, Keystone—have commits in the repo. If the merge-into-existing-privacy-tools strategy wins, Ethereum will have done for private payments what ERC-20 did for tokens: make them boring, standard and everywhere.

The amber has hardened. Now we watch who gets trapped inside—and who walks out free.