A lender or landlord asks for proof of income. The recipient proves a total and shows no single payment.

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Use

The verifier checks it with the challenge it issued:
A real proof over four testnet payments is at examples/testnet/income. It reveals which outputs were counted and each note’s nullifier, and nothing else.

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Requiring separate payments and separate payers

--min-payers needs payer tags from the payers. That makes the total one that came from several wallets.

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How it works

For each counted output the verifier reads the note commitment from the chain and builds a one-leaf Merkle tree from it. The recipient makes an Action proof against that tree, with the value commitment fixed by the verifier to ValueCommit_0(floor). The circuit’s 64-bit range checks on the note’s value and on the hidden output’s v − floor give v ≥ floor, and floor ≥ 1 forces the anchor check. One SpendAuthSig by rk covers every item. The proof shows the sum of the floors, not the amounts.

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Limits

  • It proves at least the sum of the floors the recipient chose.
  • Payments appear as outputs with nullifiers, so the verifier knows how many were counted.
  • Whoever gives the lender the proof chose the payments; a lender who needs a full history asks for a viewing key, which is the thing receipts avoid.
Code: crates/zceipt-core/src/income.rs. Test: roundtrip.rs::proof_of_income_shows_a_total_not_the_amounts.