Real-world assets,
provably backed on-chain.
Bind an off-chain asset list to an on-chain portfolio with a custodian-signed attestation. Counterparties verify the binding cryptographically — without ever seeing the assets themselves.
How it works
1.Agree on the asset list off-chain
You and your custodian settle the exact list of assets that back the portfolio — outside the blockchain, in whatever format your compliance regime requires.
2.Compute the canonical hash
Both sides independently hash the list via POST /api/custody · action:hash-assets. If your hashes match, you have a shared reference the chain can commit to.
3.Custodian signs, you submit
Custodian signs a build-message payload with their enrolled ed25519 key. You submit the signature via rwa_custody_attestor::submit_attestation.
4.Anyone verifies, no asset list required
Any counterparty calls POST /api/custody · action:verify with the attestation object id. They learn "yes, this portfolio is backed by an asset list this custodian signed" — nothing about which assets, nothing about the value.
Who this is for
- Tokenized-treasury issuers
- Bind on-chain treasury bill wrappers to the actual custody holdings without revealing the position list.
- Real estate / receivables platforms
- Prove that a portfolio is backed by an underlying loan or property pool without disclosing borrower identities.
- Fund managers issuing on-chain shares
- Give LPs cryptographic proof of NAV backing at any point in time — auditor-ready artifacts, no share leakage.
- Custodians serving crypto-native clients
- Sign attestations once. Every counterparty verification is a stateless off-chain call — no ongoing operational burden.
Under the hood
Move contract
rwa_custody_attestor.move — Sui Move, 340 LOC, 11/11 tests passing. Ed25519 signature verification, canonical SHA-256 asset-list hash, nonce + expiry gating.
Portable artifacts
Every attestation is downloadable as a canonical JSON that any counterparty can verify off-chain via a single POST request — no wallet connection required.
Composable API
/api/custody exposes hash-assets, build-message, verify, list-attestations. Off-chain flow is stateless.
Privacy by construction
Only the SHA-256 hash and custodian pubkey hit the chain. Asset list, position sizes, counterparty identities: all off-chain, all confidential.
Contract audited internally, mainnet deploy pending
rwa_custody_attestor.move is written, tested (11/11), and awaiting external audit sign-off as a Tranche 2/3 deliverable. The off-chain API + JSON artifact downloader are already live so integration work can start today.
Onboard as a custodian
Enrol your ed25519 signing key, run through the hash-assets flow with a test payload, then start issuing attestations. We'll walk you through the whole loop in a 30-min call.
Book onboarding call