QBC on the QVM, minted only against locked native QBC.

Escrow, not wrapping by promise

Locking consumes a native UTXO into the L1 escrow pallet and adds its amount to an on-chain total, TotalLocked. The QVM bridge contract mints only for a lock nonce the committee has confirmed, only once per nonce, and only if the new QVM supply stays at or below the escrow total the committee attests with it. Burning destroys the QVM tokens in the same transaction that records the request; L1 then releases the same amount as a new UTXO, never more than the escrow holds. Both chains use 8 decimals, so 1 unit is 1 unit.

A 2-of-3 attester committee, not a trustless bridge

Three independent attesters, each on a different machine with its own keys, watch finalized L1 locks and confirmed QVM burns. Two matching votes are needed to mint or release, and votes for different parameters never combine. This is a committee today: two colluding attesters could approve a false mint or release, and L1 releases are bounded only by the escrow total and the outflow limit below. Replacing the committee with on-chain proofs is future work, not a feature of this bridge.

Limits and safety switches

• Each lock is one whole UTXO between 1 and 1,000,000 QBC. To bridge part of a balance, send yourself that amount first to create a UTXO of that size.
• L1 releases are capped per rolling window of 26,182 blocks (about 24 hours). A release over the cap waits for the next window; the current cap is shown in the status panel.
• The L1 side can be paused by the chain's 2-of-3 governance multisig. On the QVM, the guardian or any attester can pause minting and burning instantly, and only the guardian can unpause, 48 hours later.
• Committee changes on the QVM need approval from the current committee, or the guardian after a 48 hour delay.

Fees and timing

• The bridge takes no fee. QVM transactions use a gas price of 0. The L1 lock is relayed for you, and the relay pays the L1 transaction fee.
• L1 to QVM: attesters act only on GRANDPA-finalized L1 blocks (blocks every 3.3 seconds), then vote on the QVM.
• QVM to L1: attesters wait for QVM confirmations, then vote on L1, and the release is subject to the outflow cap.
• Exact end-to-end times depend on finality and on the attesters, so the page tracks each step from on-chain state rather than promising a duration.