Setting the scene

What we have:

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What we need:

• The verification on Gnosis Chain chain of USDC total supply on Optimism.

How Hashi enables the Event verification:

• With HashiAPI: a offchain component used to retrieve the Storage Proof of a specific storage slot (the one holding the USDC total supply).

• With HashiProver: a onchain contract provided by Hashi which can verify the block proof provided by HashiAPI. HashiProver must be deployed on the target chain (Gnosis Chain in this case) and can be used in a custom contract which can use the Event proof verification provided by HashiProver itself.

• The proof will be verified using the latest block header that was relayed to Hashi from Optimism to Gnosis Chain (check the Hashi explorer).

Steps followed in this example:

• Fetch the storage proof for the USDC total supply on Optimism.

• Deploy a custom contract on Gnosis Chain that will verify the event proof using HashiProver.

• Submitting the proof to the custom contract.