The zkBob solution is based on several interrelated smart contracts. The main purpose of the contract subsystem is to store the current Merkle tree state inside the base blockchain. Each zkBob transaction changes the Merkle tree, so it should be processed by a smart contract. See the subsystem below, where the Pool contract is the primary contract for processing transactions.
- Operator contract helps the Pool contract to determine whether transactions can be accepted from a sender. It is used in the multi-relayer configuration to serialize the transaction sequence from the different nodes and minimize transaction collisions.