IBC Protocol

The web wallet must be able to transfer token amounts to other chains via the Inter-Blockchain Communication Protocol (IBC).

We need to be able to support the following:

  • Fungible token transfer (ICS020) from Namada to other Anoma chains
  • Fungible token transfer (ICS020) from Namada to Cosmos

What the UI will need to display to the user:

  • Select a chain (chain ID) as destination
  • Enter a channel ID for destination (e.g., channel-0)
  • Specify a receiver address
  • Specify a token
  • Specify an amount to transfer

The web wallet will need to construct a MsgTransfer struct, which will get wrapped in a normal, signed transaction and broadcasted to the source ledger (this struct is passed into the Tx data):

#![allow(unused)]
fn main() {
MsgTransfer {
	source_port: String,
	source_channel: String,
	token: Option<Coin>,
	sender: Signer,
	receiver: Signer,
	timeout_height: Height,
	timeout_timestamp: Timestamp
}
}

A populated MsgTransfer with a disabled block-height timeout (instead using a timestamp timeout), may look like the following:

#![allow(unused)]
fn main() {
MsgTransfer {
	source_port: PortId("transfer"),
	source_channel: ChannelId("channel-0"),
	token: Some(Coin {
		denom: "atest1v4ehgw36x3prswzxggunzv6pxqmnvdj9xvcyzvpsggeyvs3cg9qnywf589qnwvfsg5erg3fkl09rg5",
		amount: "1.23456"
	}),
	sender: Signer( "atest1v4ehgw36xvmrgdfsg9rrwdzxgfprq32yxvensdjxgcurxwpeg5mrxdpjxfp5gdp3xqu5gs2xd8k4aj"
	),
	receiver: Signer( "atest1d9khqw36xu6njwp4x5eyz334g4zrjvz9gyungv6p8yurys3jxymrxvzy89pyzv2pxaprzsfedvglv2"
	),
	timeout_height: Height {
		revision: 0,
		height: 0
	},
	timeout_timestamp: Timestamp {
		time: Some(Time(PrimitiveDateTime {
			date: Date {
				year: 2022,
				ordinal: 124
			},
			time: Time {
				hour: 14,
				minute: 15,
				second: 33,
				nanosecond: 0
			}
		}))
	}
}
}

NOTE Unlike with tx_transfer, the amount we pass with the Token is not submitted in micro-units, but as a regular f32 value. No conversion is needed in the web wallet.

Once this transaction is unwrapped and validated, apply_tx will invoke IBC.dispatch() (see: https://github.com/anoma/anoma/blob/master/wasm/wasm_source/src/tx_ibc.rs).

When this is executed on the source chain, the balance will be deducted on the source account, so we need to reflect this in the interface. If the transaction succeeds, query the balance for that token and display to the user.

Testing

Instructions for setting up local Namada chains, along with the Hermes relatyer (ibc-rs) can be found here:

https://hackmd.io/@heliax/BJ5Gmyxrq

The wallet UI will need to be configured to connect to the source chain from which you want to transfer tokens. The user will have to enter a valid channel ID in the interface, in addition to an established address on the destination chain (the receiver).

Configuration

The wallet web app should accept a configuration per-environment that will contain not only the default network, but the possible destination networks that the user can transfer tokens to. We need the following information for each, at a minimum:

  • A user-friendly alias naming the network
  • Destination URL
  • Destination Port
  • A non-default portId, if necessary, though in most cases, the default of transfer would likely be used.

Resources

Cosmos relayers: