Being cross chain, can you explain off chain chain module? How to setup and submit blocks from Chain A to Chain B

[patidarmanoj10]

Being cross chain, can you explain off chain chain module? How to setup and submit blocks from Chain A to Chain B

[maxrobot]

Hi,

There is no default off-chain module or relay required in the Ion framework.

Ion aims to facilitate trustless interoperability, where blocks passed from another chain can be validated to see if they were really included in the other chains ledger/blockchain.

Let me give more context.

Given two Ethereum chains A and B. In order to pass state from A to B, blocks from chain A would be encoded and used as an input arguments of a function in a validation contract on chain B.

The validation contract on chain B would be specific to the consensus mechanism used on chain A, i.e. if chain A uses Clique PoA then it must be able to validate these blocks. If a block is validated then it is persisted in a block storage contract where users can query the state transitions that occurred in this block.

This is at a high-level how the Ion framework is designed.

However, there is no relay that performs the passing of blocks/state automatically. Rather it is expected that users would decide how they wish to submit blocks between chains dependent on their use case.

For testing and development purposes the Ion-CLI has a number of features to assist in encoding blocks and interacting with smart contracts. It is not designed to be a relay that submits blocks automatically, but feel free to add this feature.

For more details on Ion and our vision please check out this post, here, and the Ion wiki here.

I hope that answers your question :) else ask more!

[patidarmanoj10]

Thanks for answering in details. It clears my confusions. I was wondering if all blocks need to submit in chain B to validator tx xyz exist in Chain A? Chain A has 1000 blocks and only two block contains some tx which is suppose to validated in chain B.

[patidarmanoj10]

Also, If bad actors submitting their own fake blocks in chain B which actually does not exist in chain A but structure of the block is valid. Trie , root, RLP looks okay but it doesnt blong to chain A. or we assume only whitelisted validators are submitting blocks?

[Shirikatsu]

If bad actors submitting their own fake blocks in chain B which actually does not exist in chain A but structure of the block is valid

Ion is separated into validation and storage layers. Submitted blocks are only accepted if it passes correctness verification in the validation layer. This layer is responsible for checking the consensus result of the originating chain to ensure that the block being submitted has been committed to the chain before storing it.

I was wondering if all blocks need to submit in chain B to validator tx xyz exist in Chain A?

This all depends on the validation layer.

In Clique PoA consensus, validator votes are tallied and changes to the validator set are made after a threshold. This therefore requires the validation layer to replicate this to ensure that votes are collected properly to reflect validator set changes. When new blocks are submitted, the signature on the block is checked against the known set of validators before storage.

Other validation mechanisms (that replicate source chain consensus/finality) may or may not require sequential block submission.

[Fergly]

However, there is no relay that performs the passing of blocks/state automatically. Rather it is expected that users would decide how they wish to submit blocks between chains dependent on their use case.

Hi @Shirikatsu, do you envisage any issues with using a Chainlink oracle job to achieve trustless automation of passing of the validation blocks? Thanks.

[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 5 days