Implementing the xcall specification for BSC

[pragyanshrestha-ibriz]

Overview

Implementation for xcall service for BSC and ICON

Assumptions

• It is only considered for Icon Bridge
• We do not need to implement the xcall specification from scratch and can use the one already existing in the BTP Repo
• Only Java SCORE and Solidity will be considered for this piece of work

Potential Changes

• Implement dapps / some other service handlers to test

[izyak]

XCall Contract

• Current btp xcall contract is not stricly implemented with reference to IIP-52 on the fee part.
• Whether they are not strictly implementing xcall or they want to change the standard is not clear. There is a PR for the IIP-52, which has not been approved or merged into IIP-52.
• Fee handling has been changed recently on btp xcall
• Basically, need to be clear about the fee structure for xcall before implementation and restrictions on contracts that can call xcall.
• Based on the current implementation of xcall in btp
  • xcall does not restrict any services to use it. Provided the user has provided protocol fee for xcall and relay fee. Other services interact with xcall and not bmc after that.
  • Currently, on icon-bridge fee is taken on the BTS Contract. If xcall is left open for any service to use, based on our current implementation of BMC, we won't get relay fee, but our relay has to incur the transactions. If the structure of BMC has to change for this, the estimation will change.

[pragyanshrestha-ibriz]

Putting this Epic on hold to further analyse the implementation of IBC.