Use sovereign accounts of sending chains to pay relayer rewards

[svyatonik]

In bridges-v1 we are using into_account_truncating on RewardsAccountParams structure to compute AccountId that will be used to pay relayer rewards.

This is not XCM-friendly. Also it means that the sending chain (e.g. asset hub) needs to maintain two accounts at bridge hub - one for paying XCM fees and another to pay relayer rewards. Let's remove RewardsAccountParams and use SA of sending chain for both purposes.

[bkontur]

@svyatonik
Can I take it or are you working on that?
I've just added claim rewards stuff to Ro/Wo demo scripts :) paritytech/polkadot-sdk@559b954

[svyatonik]

@bkontur No, I'm not working on that now - please take it if you want :)

[bkontur]

xcm fees will be also paid from SA of asset hub on BridgeHub,
so it is ok to use the same SA account for claiming rewards?

[svyatonik]

I think - it is fine. That's the point of this issue. But if you have some concerns - please share. I may be wrong here

[bkontur]

no concerns, it simplify stuff, and it also make sense that SA of AssetHub manages rewards.
just wonder if it is ok from security-audit point of view.

[svyatonik]

just wonder if it is ok from security-audit point of view.

I'm not the right person to answer that :) We may impl-then-ask or ask-then-impl. But from my PoV, I see no problems with that.

[acatangiu]

@bkontur let's prioritize this post initial launch and get it in a subsequent patch release