Prove It Without Showing It

To rent an apartment, you hand a stranger six months of bank statements. To join a members-only community, you upload your ID. To claim an airdrop, you give up your phone number to show you're a person. Each time, you reveal far more than the question asked. The landlord only needed to know you earn enough.

Most checks are yes-or-no questions

Does this person earn more than a set amount each month? Are they over 18? Is their account more than a year old? Were they on site at 8am? Did they pass the exam? Answering any of these shouldn't require handing over the whole file.

Zero-knowledge proofs answer the question and nothing else. The user's device produces a small cryptographic proof that the statement is true. Your app checks the proof. The underlying data stays with the user.

Three ways I build it

zkTLS with Reclaim: facts from websites people already use

Your user's bank, payroll provider, exchange or social account already knows the fact you need. With Reclaim's zkTLS, the user logs into that site as usual and produces a proof that it showed what they claim: income above a threshold, an account older than two years, a completed order. You receive a proof of the claim, never the statement or the password. I verify it in your backend, or on-chain on EVM chains or Starknet, and gate an action on it: a loan offer, an airdrop claim, an access pass. zkTLS Proofs with Reclaim.

Noir and Garaga: proofs made in the browser

When the secret lives on the user's device, such as a location, a date of birth or a membership credential, I write a Noir circuit for exactly what's being proven and generate the proof in the browser with NoirJS and Barretenberg, benchmarked on ordinary phones. Garaga generates a Cairo verifier on Starknet, so a contract can act on the proof directly. Uses include a private clock-in that proves a staff member was inside the geofence without sending their coordinates, anonymous voting, proving an exam pass without revealing the score, and sealed-bid tenders. Browser ZK Proofs with Noir & Garaga.

Custom circuits, and reviews of existing ones

For protocols with their own needs, I write circuits in Noir or Circom from a precise statement of public and private inputs, measure proving time and verification gas, and generate verifiers in Solidity or in Cairo through Garaga. I also review existing circuits for missing constraints, the class of bug that lets anyone forge a valid proof. ZK Circuits & Verifiers.

Privacy for money too

Public blockchains show every balance to anyone with an address. Privacy pools and shielded balances fix that for businesses: resting funds move into a shielded pool, deposits are screened through an association set so funds stay provably clean, and an auditor key can give your accountant a view. WeSelling, my own business software, lets businesses move resting USDC into a Tongo pool on Starknet, and it states plainly what that privacy covers and what it doesn't.

What I won't skip

A circuit with a missing constraint can accept a forged proof, and nobody notices until someone exploits it. Every circuit I write comes with tests that deliberately try to forge proofs with bad inputs, and documentation an auditor can follow. Before any code, we write down what's proven, what stays private, and from whom.

Answer the question. Keep the file.

What it costs

zkTLS proofs with Reclaim start at $350. Browser proofs with Noir and Garaga start at $750. Custom circuits start at $600. Privacy pools and shielded payments start at $700. Each has three packages on its gig page.

Tell me about your business and I'll tell you what I'd build first: start here or book a free call.