The Bridge

The bridge is a set of vault contracts on Ethereum — Base and Linea are planned — and a light client on STRATO that can verify what happened on those chains.

Deposit

1. You send USDC to the vault on the source chain, naming your STRATO address and trading account.
2. The vault escrows the USDC and emits a deposit event.
3. That event is proven to the light client on STRATO — a proof that the source chain really did record the deposit.
4. The minter credits USDλ to your account against the proven deposit.

Nobody vouches for the deposit; a contract checks the proof. Producing that proof needs the source chain's block to be final — about 13 minutes on Ethereum — so a new account is not left waiting. A zero-fee house filler fronts the deposit the moment it is seen on the source chain, about a minute in: it credits your account from its own USDλ, then is reimbursed when the trustless proof settles at finality. You trade in a minute; the proof squares up the filler behind the scenes.

Withdraw

1. You sign a withdrawal inside the exchange, naming an amount and your owner address.
2. The withdrawal is included in a block, and the block is proven and settled on STRATO. The proof attests that your balance covered it.
3. The USDλ is redeemed and the vault on the destination chain releases USDC to your address.

There is no approval step on the exchange's side. The vault releases USDC against a proven withdrawal and against nothing else.

Why this is safer than a typical bridge

Most bridges have a set of signers who attest that a deposit happened; if enough of them collude, they can mint what was never deposited. Here the minting contract accepts only a light-client proof of the source chain. The set of addresses that can mint USDλ is fixed at deployment and can only shrink, so the guarantee a holder verifies once holds forever.