The biggest challenges came from building the new private trading mode. We faced bugs while encrypting orders and then correctly decrypting them before execution, as even small encoding mismatches caused transaction failures. Managing off-chain trade data using Merkle trees also introduced errors when generating and verifying proofs, especially when syncing tree roots with the on-chain state. Additionally, writing and debugging the zk-SNARK circuits to validate private trade batches without revealing individual positions was complex and required multiple iterations. We overcame these by adding extensive test cases, building custom debug tools for tree verification, and closely integrating circuit simulation with the Solidity contract logic