Soft Confirmations

Issued by the sequencer, soft confirmations in Citrea provide soft-finality for transactions in a block, offering users rapid feedback while the rollup awaits finalization on the DA layer. They represent interim state updates within the Citrea rollup.

Structure

Each soft confirmation encapsulates essential information about a block:

• Rollup Block Information: The information of corresponding rollup block.

• Previous Hash: The hash of the preceding soft confirmation, forming a chain of blocks that prevents replay attacks and ensures correct ordering.

• DA Block Information: The height, hash, and the transaction commitment data of the associated DA block on Bitcoin.

• L1 Fee Rate: The fee rate on Bitcoin L1, relevant for calculating transaction costs.

• Transactions: Transaction data included in the block.

• State Root: The root hash of the rollup state after applying the transactions in this soft confirmation.

• Signature: The sequencer's signature on the soft confirmation data.

• Public Key: The sequencer's public key used to verify the signature.

• Deposit Data: Information about deposit transactions from the BitVM-based Clementine bridge.

• Timestamp: The timestamp of the block, recording when it was produced by the sequencer.

The structure above is signed and distributed to the network.

Soft confirmations form the basis for sequencer commitments, which are published to the DA layer for finalization.