How do proof systems function?
Cross-chain proof systems verify that a token transfer has occurred on a source chain before authorising a corresponding credit on a destination chain. Each proof format carries distinct trust assumptions and verification latency characteristics that determine its suitability for gaming platform transfer contexts. Merkle proof systems verify transfer inclusion through hash path reconstruction against a known state root. Zero-knowledge proof systems compress transfer validity into a compact proof that the destination chain verifies without accessing the underlying transfer data. Optimistic systems assume transfer validity and open a challenge window before finalising the destination chain action. https://crypto.games/ proof system selection determines how quickly a deposit confirmed on one chain produces a credited balance on another, and how securely that credit is protected against unverified transfer claims submitted to the destination chain verification contract.
How are transfers verified on the chain?
- Deposit event capture – Verification begins when a deposit transaction confirms on the source chain and the bridge contract emits an event log entry recording the depositor address, token contract address, transfer amount, and block number. The proof generation process draws directly from this confirmed on-chain event rather than off-chain transfer records.
- Merkle proof construction – A proof is constructed linking the deposit event to the source chain block’s receipt root through a sequential hash path. The destination chain contract recomputes this path and compares the resulting root against the stored source chain receipt root, confirming deposit inclusion without requiring full block data at the destination.
- Zero-knowledge proof generation – Zero-knowledge systems process deposit event data through a proof circuit, producing a validity proof without exposing transfer parameters to the destination chain. The destination contract runs the verification algorithm against the submitted proof, confirming transfer validity through mathematical verification rather than data reconstruction.
- Light client state root synchronisation – Destination chain verification contracts must hold accurate source chain state roots corresponding to the block height referenced by each proof. Light client contracts update stored roots by processing relayed block headers, making state root synchronisation a prerequisite for deposit proof acceptance at the destination contract.
- Duplicate transfer prevention – The destination chain contract records the source chain transaction hash of every verified transfer. Before processing any new proof, the contract checks the submitted hash against this record. A hash already present causes the verification call to revert, preventing duplicate credits regardless of how many times the same proof is submitted.
- Destination chain credit execution – The destination contract executes the credit action for the verified deposit as soon as the verification process has been completed. By reading the credit amount and recipient address directly from the verified proof parameters, the credit is guaranteed to reflect the confirmed source chain deposit accurately without relying on the data from the submission call.
Using cross-chain proof systems, it is possible to connect deposit confirmation on source chains with credit execution on destination chains via layers of verification. The proof format selection, the state root synchronization, and the duplicate prevention all play important roles in determining how accurate the verification of gaming platform transfers across connected chain environments will be.