Accepting a proof

#Choose where to verify

#1 · Ask for a proof

Build a request at /request: the threshold, your identifier, an expiry, and optionally a period (so reuse shows), an unmoved-since block, a response deadline, and a binding to the holder’s Solana account. Hand the link to the holder.

#2 · Verify with the CLI

curl -s $SITE/api/anchors     > anchors.json
curl -s $SITE/api/revocations > revocations.json
pof-verify check proof.pof --audience pof-credit:usdc-pool-1 \
           --anchors anchors.json --revocations revocations.json \
           --epoch 202610 --seen registry.json --dormant-since 4410000
# Valid · 500.00000000 ZEC at least · anchor 3491040
echo $?   # 0 valid · 1 invalid · 2 expired · 3 malformed · 4 could not run

With --json it prints the full result, including the tags to append to your registry. It reads local files only, so it can gate CI or a batch job.

#3 · Verify in the browser

pof-wasm is the same Rust crate compiled with wasm-bindgen. Its verifying keys are embedded (a native test proves they equal a fresh keygen), so it warms up in about 300 ms and verifies in about 90 ms. The boundary is pure: bytes, the anchor table and the revocation list in; a verdict out.

import init, { verify } from '/wasm/pof_wasm.js'

await init()
const anchors = await (await fetch('/api/anchors')).text()
const revoked = JSON.stringify((await (await fetch('/api/revocations')).json()).secrets)
const now = BigInt(Math.floor(Date.now() / 1000))
const result = JSON.parse(verify(bytes, 'pof-credit:usdc-pool-1', now, anchors, revoked))
if (result.verdict.kind !== 'Valid') refuse(result.verdict)

Run it in a Web Worker, as the site does, so the warm-up never blocks the page.

#4 · Verify on Solana

A Solana program cannot verify a Halo2 proof over Pallas or read Zcash state. So pof-attest runs the verifier and signs a domain-separated 139-byte message, and pof-gate checks that signature through instruction introspection:

ix 0  Ed25519SigVerify111111111111111111111111111   verify(attestor, message, signature)
ix 1  pof-gate::submit_attestation(subject, message)
        1. parse and domain-check; verdict = Valid; claim kind known
        2. slot within max_age_slots; expires_at in the future
        3. count distinct allowlisted keys that signed exactly this message in
           earlier Ed25519 instructions whose offsets all point into themselves
        4. count ≥ threshold (k of n)
        5. create ClaimReceipt PDA [b"receipt", subject]   ← one proof, one receipt

A consumer program reads the receipt, checks the audience, the claim value, the expiry and that the signer is the beneficiary, then calls mark_consumed by CPI, signed by the beneficiary and by the consumer program’s own [b"consumer"] PDA. pof-credit is the worked example: see Credit lines.

Read the trust model before you rely on it, and run your own attestor.

#Integration checklist

• Load only the anchors you trust (mainnet only, if you only accept mainnet).
• Fetch the revocation list at decision time, not once at start-up.
• Name a period in your requests and keep a registry of accepted tags, or reuse is invisible to you.
• Set --tip-height and --max-anchor-age when “unspent” must be recent.
• Treat anything but Valid as a refusal, and show the holder the verdict’s reason.
• Ask for a fresh proof at each decision: a proof is “as of” one block.