cosmos-sdk/docs/spec/ibc/ibc.md

IBC Specification

This is a living document and should be edited as the IBC spec and implementation change

Engineering Philosophy

The goal is to get the simplest implementation working end-to-end first. Once the simplest and most insecure and most feature-less use-case is implemented we can start adding features. Let's get to the end-to-end process first though.

MVP One

The initial implementation of IBC will include just enough for simple coin transfers between chains, with safety features such as ACK messages being added later.

IBC Module

• handles message processing

type IBCOutMsg struct {
  IBCTransfer
}

type IBCInMsg struct {
  IBCTransfer
}

type IBCTransfer struct {
  Destination sdk.Address
  Coins       sdk.Coins
}

Relayer

Packets

• Connect to 2 Tendermint RPC endpoints
• Query for IBC outgoing IBCOutMsg queue (can poll on a certain time interval, or check after each new block, etc)
• For any new IBCOutMsg, build IBCInMsg and post to destination chain

CLI

• Load relay process
• Execute IBCOutMsg

MVP2

• IBCUpdate is added, making it able to prove the header.

IBC Module

type IBCOutMsg struct {
  IBCTransfer
}

type IBCInMsg struct {
  IBCTransfer
  Proof           merkle.IAVLProof
  FromChainID     string
  FromChainHeight uint64
}

// update sync state of other blockchain
type IBCUpdateMsg struct {
  Header tm.Header
  Commit tm.Commit
}

type IBCTransfer struct {
  Destination sdk.Address
  Coins       sdk.Coins
}