Here is an example of some helper contracts that would make it easy for a single trusted party to offer an IOU:

https://gist.github.com/anonymous/6befb1d7b9a421207134ce6c1f9662c7

One contract would sit on the ethereum chain and simply emit an event that would alert a web3 script that could then generate the signed data for claiming the token on the nekonium chain, technically you dont need a contract for this but when it comes to redeeming the ETH funds this is the contract that allows a user to do that without a transaction from the trusted party, just their signature of the specific claim data.

The other contract is the token for the nekonium chain which allows anyone to generate your iou given the signed data of the claim from the trusted party. It contains a burn function that emits an event for the trusted party to be alarted to publish the claim for ETH on the other contract.

I have not put fees into this system but it would be trivial to add.

Some means of publishing the signed data would also be needed but with this system it would be relatively easy for anyone to audit the behaviour of the trusted party by comparing the emitted events of one contract against the claims on the other contract on the other chain.

All signatures are a hash of the data for the claim including an id and the contract address. This should prevent replay attacks if the contracts are simply deployed on each chain although in the event of a chain split having additional replay protection might be needed.



Feel free to donate nekonium tokens if you like my ideas: 0x0283b7d0d2224dd22f6bcecf4eb0cebdf8f5d282