Privacy isn’t a switch. It’s a design decision. “We really need to treat data as toxic waste by default.” That was Vitalik at Devcon Mumbai. It can sound anti-transparency. I read it differently: as a design principle. Collect less, store less, expose less. Public blockchains chose one default: everything visible. For small flows that’s mostly harmless. For institutions it’s a real problem. According to Primus’s docs, a visible position size and timing can reveal a trading desk’s strategy and invite front-running. The usual framing is binary: expose data to make it verifiable, or keep it private and lose the ability to use it onchain. Primus’s docs describe this tension directly: the most valuable off-chain data is also the most sensitive, and today it often can’t be both used and protected. One response is to build a new privacy chain. Primus argues that’s unrealistic, since liquidity, users and integrations don’t migrate overnight. Their alternative is a pluggable layer added to ecosystems that already exist. That’s their argument, and privacy-chain builders would disagree with it. Two tools sit in that layer, per the docs: - zkTLS: verify that data is authentic without revealing it - FHE: compute on encrypted data without decrypting it One answers "is it true?" The other answers “can it be used without being exposed?” Primus’s own post on Vitalik’s talk makes the point simply: privacy is not about hiding everything. I’d go one step further. Privacy isn’t a switch, it’s a decision made per piece of information: what must stay private, and what must be provable. To be clear, a philosophy isn’t proof of a working product. Any specific design still has to show what is actually hidden, who runs the computation, and how its claims get verified. I’ll dig into specific designs in follow-up posts. My take: for institutional finance, the useful question isn’t “private or transparent?” It’s “private from whom, and provable to whom?” Where do you think onchain finance gets this wrong most often: what it hides, or what it can prove? @primus_labs