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Vouch · shielded pool $1.7B · claims proven 0 · viewing keys surrendered 0 · Ironwood · block 3,491,040

Oil painting: in a gaslit iron-and-glass hall, a notary raises a single card sealed in red wax while a crowd watches. Everything else in the hall is covered.

Prove whatyou hold.Reveal nothing else.

Zcash gives you one disclosure tool: a viewing key that reveals everything you have ever received, permanently. Vouch proves a single fact instead: enough to clear an exit, open a credit line or back a reserve.

Verify a proof

Built on Zcash · Ironwood pool · Solana

THE ONLY TOOL YOU HAVE

A viewing key is all or nothing.

Zcash hides everything by design. The only disclosure tool it gives you is a viewing key, and a viewing key is all-or-nothing: hand one to a lender, an accountant or an OTC desk and they see every payment you have ever received, permanently, including the ones that have nothing to do with them.

So nobody discloses. And because nobody discloses, more than $1.7 billion of shielded ZEC cannot be borrowed against, pledged, underwritten or presented to a counterparty. The money is there. There is no way to show it is there.

Oil painting: a bank clerk opens a ledger and an endless ribbon of pages pours onto the floor while onlookers read them.
A viewing key: every page, to anyone holding it, forever.

$1.7B

of ZEC sealed in the shielded pool when Ironwood activated.

0

ways to prove any of it without showing all of it.

1

disclosure tool, and it reveals everything, forever.

Oil painting: on a lender's desk, an overstuffed portfolio spills every paper its owner has; beside it lies one small card sealed in red wax, and the lender reaches for the card.

SIDE BY SIDE

Two ways to answer the same question.

A lender asks whether you hold at least 500 ZEC. You can hand over a viewing key and open every payment you have ever received, or you can send one line that answers only that question.

Vouch proves exactly one fact — you hold at least 500 ZEC — to one named lender, until one named date. Your balance, your notes, your addresses, your history and your counterparties stay exactly where they are.

Viewing key11 disclosures

You share a viewing key.

Everything opens, permanently.

Balance
4,018.20417300 ZEC
Every payment received
1,284 notes since March 2021
Every amount
to the zatoshi
Every memo
“inv 4471 — thanks, see you Thursday”
Every counterparty
312 distinct senders
Every address
u1d88rz8hu…dmskmt
Every date
back to the wallet’s birthday
Unrelated income
salary, OTC fills, gifts
Next week’s payments
visible on arrival
Next year’s payments
still visible
Revocation
impossible — forever
Vouch proof1 disclosure

You send a Vouch proof.

One line opens. The rest never will.

Holds ≥ 500 ZEC at block 3,491,040

Balance
Balance: withheld
Payments
Payments: withheld
Amounts
Amounts: withheld
Memos
Memos: withheld
Counterparties
Counterparties: withheld
Addresses
Addresses: withheld
Dates
Dates: withheld
Other income
Other income: withheld
Future payments
Future payments: withheld
History
History: withheld

The viewing-key column is an illustrative holder, not a real wallet. The proof column is exactly what a threshold proof carries.

FOUR STEPS

A proof is a transaction that is never sent.

  1. Oil painting: a gloved hand stops a brass chronometer at one moment.

    01

    Pin a moment

    The prover takes a snapshot of the chain at one finalised block. Every proof is “as of” that block, which is what makes it checkable and what makes it expire honestly. For “unmoved since”, the notes must also be in the tree at an earlier block the verifier names.

  2. Oil painting: a clerk on a ladder threads a path through an archive of pigeonholes.

    02

    Locate the notes

    With keys derived from your seed, the prover finds your notes in that snapshot, builds a path from each one to it, and shows each is unspent without revealing it. This ties the claim to real, on-chain money.

  3. Oil painting: a letter is signed, then placed in a drawer instead of the post.

    03

    Sign without sending

    The prover reads your seed from a local file and signs with the spending key it derives. The seed never leaves your machine. The result is transaction-shaped and is never broadcast.

  4. Oil painting: a notary presses a brass seal into red wax on a single card.

    04

    Produce the proof

    Claim, audience, expiry and evidence are packed into one file. For a threshold, the amount is proven to clear the bar without being revealed.

NO BROADCASTNothing is broadcast. The prover reads your seed from a local file, builds and signs the transaction on your machine, and discards it. The seed never leaves your machine.

WHY IT MATTERS

One fact is enough to act on.

Oil painting: at a bank counter a borrower hands over one sealed card; his own strongbox stays closed at his feet.
01 / 03Exits

Exits that clear

A swap rail learns the coins predate block H and have not moved since.

And that they are the exact notes in the deposit, not a wallet history.

Oil painting: a shopkeeper and a customer shake hands over a sealed card; her purse stays closed.
02 / 03Collateral

Collateral without custody

A lender learns the position clears their bar, and sees it if the same coins come back twice.

The ZEC never leaves Zcash and nobody else holds it.

Oil painting: a trader studies a sealed card beside an hourglass that has nearly run out.
03 / 03Reserves

Reserves that go stale on time

A treasury proves its total across many proofs, no note counted twice.

A Solana token mints only within it, and only while the proof is fresh.

THE STACK

Built on what already works.

Oil painting: a world's-fair ground at dusk, divided by a river. Pavilions on one bank are joined to a glass pavilion on the other only by telegraph wires; there is no bridge.
No bridge crosses the river. Only a signed message does.
  1. 1 · Ironwood Pavilion
  2. 2 · The Prover’s Workshop
  3. 3 · The Verifier’s Hall
  4. 4 · Attestor’s Signal Tower
  5. 5 · Solana Pavilion

$1.7B

sealed into Ironwood at activation.

28 Jul 2026

Ironwood activates. Orchard is now the legacy pool; Vouch targets Ironwood.

6

verifier checks: format, expiry, revocation, audience, anchor, proof.

0

keys transmitted. The prover runs on the holder’s machine.

Components

09 pieces · 1 verifier, compiled twice

Zcash side

On the holder’s machine, and in anyone’s browser.

  • 01pof-coreRustClaim types, the proof envelope, encoding. No I/O, no network.
  • 02pof-anchorRust CLIRebuilds both roots from public compact blocks; checks the note-commitment root against lightwalletd.
  • 03pof-zkRust · Halo2The delegation circuit, twice: with the threshold added, and with the notes revealed for exit certificates. No trusted setup.
  • 04pof-proveRust CLIReads wallet state, pins the anchors, drives the circuit: a proof, an exit certificate or a reserves batch.
  • 05pof-verifyRust → WASMSix checks, cheapest first. One implementation, compiled twice.

The crossing

The one trusted hop.

  • 06pof-attestRust serviceRuns pof-verify and signs the verdict for chains that cannot read Zcash. Serves rails: certificates, deposit match, webhooks.

  • Trust-minimised, not trustless.

    A Solana program cannot check a Zcash fact by itself: wrong curve, no access to Zcash state. So verification by a Solana program goes through an open-source attestor that runs the same verifier and signs the result. Anyone can run one; a Zcash light client on Solana would remove it.

Solana side

Sees a signed verdict. Never a key, never a note.

  • 07pof-gateAnchorTurns a signed attestation into a replay-protected fact on Solana.
  • 08pof-creditAnchorExample consumer: opens a credit line against a threshold receipt.
  • 09pof-reserveAnchorTurns an attested reserves batch into a feed; a token mints only within it, while it is fresh.
Oil painting: at night a crowd faces a glowing pavilion; above its door hangs a single card sealed in red wax, and every other window is curtained.

Prove one thing. Keep the rest.

Verify a proofRequest a proof