Sig Network is a signing network that gives a Midnight contract its own account on Ethereum. Users keep their balances and identities shielded on Midnight, and their activity settles on Ethereum against existing liquidity at the prices Ethereum venues already quote.
Sig Network is the signing network behind Nightmode, and its tooling is open to any team building on Midnight.
Privacy without migration
Developers that want to build applications with privacy features have usually had to switch chains to get it. Rebuilding and redeploying on a privacy chain is a big hurdle. It means leaving behind the liquidity and users an application has already built. Few teams with a working product will make that trade, so privacy remains something users ask for and rarely receive.
Sig Network removes the barrier of rebuilding and redeploying on a new chain. An application stays on Ethereum and places its private logic and its users’ records on Midnight. Midnight becomes a privacy layer that existing applications can reach, rather than a destination they have to migrate to.
'Midnight was built so that privacy and accountability can sit in the same application. Sig Network carries that to applications already running on Ethereum, with user balances and identities shielded on Midnight and a complete record the application can disclose when required'.
Gareth Christian-Lim, Director of Growth, Midnight Foundation
How it works
Sig Network holds the private key to an Ethereum account on behalf of a Midnight contract and signs only what that contract requests.
- The Midnight contract executes the logic. A Compact circuit validates the user’s request, burns their shielded claim and queues a single Ethereum transaction.
- Sig Network signs. A threshold of independent signers produces a standard Ethereum signature. No individual signer can act alone.
- Ethereum settles. The transaction executes from the contract’s account, and the outcome is attested back to Midnight, where the user’s balance is updated.
Nothing is bridged or wrapped. The assets remain on Ethereum throughout, in an account the Midnight contract controls. What passes between the two networks is a signature.
To Ethereum, that account looks like any other. It receives deposits, swaps on Uniswap, supplies to Aave and sends withdrawals. Amounts and timing on this public leg remain visible, as they would for any Ethereum account. The record of individual user activity and balances stays shielded on Midnight, so personally identifying information and transaction histories are not visible on Ethereum.
What teams can build
- Private trading on public venues. Orders net against each other inside a pool on Midnight, and only the net amount trades on Uniswap, from a single account at Uniswap’s price.
- Shielded yield. The pool aggregates funds and lends on Aave through a single account, which means the lending income on Ethereum cannot be linked back to individual depositors.
- Private positions on public markets. Users take positions on a prediction or perpetuals venue through a pool. The venue sees the pool, and the pool holds the record of each client.
- Shielded deposits and withdrawals. Funds arrive from any wallet or exchange at a one-time address and leave to a fresh one, with no address reused along the way. Suited to wallets and payment applications.
Teams can adopt this in stages. The starting point is a private pool that shields data while moving assets to an application that people already use. From there, logic can move onto Midnight one layer at a time, beginning with strategy and routing and later extending to lending. Every layer that remains on Ethereum keeps its access to Ethereum liquidity, and each team decides where that line falls.
'Teams shouldn’t have to rebuild an application to make it private. Keep your app on the chain it’s on and add Midnight’s privacy without redeploying. Start with a private pool in front of something your users already trust, then bring more of the logic onto Midnight when it makes sense for you.'
David Millar-Durrant, CEO, Sig Network
Compliance written into the contract
Personal and financial data stays off the public network. The contracts behind each application still carry the compliance controls a regulated institution would need to build any of the use cases above. Because the pool is an ordinary Ethereum account, the screening tools regulated venues already use apply to it without change. Each application also holds its own accounts, so its funds never sit alongside those of parties it does not trust.
The Midnight contract sets the terms. It defines which deposits it accepts and credits only those that pass screening. What users disclose to take part, and who may ask for it, are fixed in the same contract. The application keeps a complete record on its Midnight ledger, and through selective disclosure, asset issuers can fully reconcile ownership without information leaking on chain.
Start building
Sig Network is live on Midnight stagenet, supporting deposits, Uniswap swaps, Aave supply and withdrawals to any address on Ethereum.
Developers can import the Signet module into Compact and queue Ethereum transactions directly from their circuits. The repository example includes a complete ERC-20 vault covering deposit, withdrawal, swap and supply, along with deploy tooling and integration tests. For teams that prefer Rust, MinoCrab is an experimental embedded language that compiles the same contracts with standard Rust tooling.
- Read the Sig Network documentation
- Explore the example contracts
- Try the demo application
- Watch the Nightmode demo with Sig Network
Check out the ecosystem catalog to learn more about the partners across the Midnight ecosystem.