Introduction
Hashi is the Sui native Bitcoin orchestrator. It secures native BTC for use
on Sui and represents that BTC onchain as hBTC. This documentation is the
canonical description of Hashi's design, how it operates, and how to
use, integrate, and run it.
What is Hashi?
Hashi is a protocol that lets you move BTC onto Sui and back without handing your coins to a single custodian. A committee drawn from the Sui validator set holds the BTC in a shared pool and signs Bitcoin transactions together using a threshold Multi-Party Computation (MPC) protocol. No single member holds the signing key, and the key moves to each new committee as the Sui validator set changes.
A second, independent signer called the Guardian co-signs every withdrawal from inside a cloud enclave. Every deposit address requires both the committee and the Guardian to spend it, so a compromised committee cannot move funds on its own. See Guardian and Bitcoin Address Scheme for the details.
How does Hashi manage Bitcoin on Sui?
Hashi supports 2 flows, deposit and withdraw:
- Deposit: Every Sui address has its own unique Bitcoin deposit address.
You send BTC to yours, then tell Hashi about the transaction on Sui. After
the committee confirms the deposit on Bitcoin, Hashi mints an equal amount
of
hBTCto your Sui address. - Withdraw: You submit
hBTCand a destination Bitcoin address on Sui. Hashi burns thehBTC, builds a Bitcoin transaction from its pool, signs it with the committee and the Guardian, and broadcasts it.
Deposits are free and withdrawals pay only the Bitcoin miner fee. There is no protocol fee. See User Flows for the end-to-end picture and Fees for the numbers.
What is hBTC?
hBTC is a fungible Coin<BTC> on Sui that Hashi mints on deposit and burns
on withdrawal. Each hBTC corresponds to BTC that the committee and Guardian
hold in the Hashi pool. Because hBTC is a standard Sui coin, you can use it
in any Sui app, for example as collateral in a lending protocol.
hBTC is the only coin Hashi creates. There is no HASHI governance, utility,
or airdrop token. Committee members govern the protocol by voting onchain with
their validator stake weight. Treat any HASHI token offering, presale, or
airdrop as an imitation.
Where do I start?
The documentation has 5 sections. Choose the one that matches what you want to do:
- hBTC: Move BTC in and out. Start with User Flows, then follow Deposit BTC, Withdraw BTC, and Cancel a Withdrawal, and check the hBTC FAQ.
- Protocol: How Hashi works. Start with the architecture pages, then read the Deposit and Withdraw lifecycles, Reconfiguration, governance, security, and Fees.
- Integration: Build on Hashi with the TypeScript SDK.
- Validators: Join the committee and run a node. Start with the Run a Hashi Node and keep Hashi Node Backups nearby.
- Reference: Onchain configuration parameters, plus the Move package, the gRPC API, and the Rust API.