Action: Ics20Withdrawal

The Ics20Withdrawal action allows a user to transfer funds from Penumbra to another chain using over an existing IBC connection. The action contains the following fields.

• amount — a transparent value consisting of an amount (u128)

• denom — the asset metadata of the asset being transferred, only the base_denom is used

• destination_chain_address — the address on the destination chain to send the transfer to

• return_address — an ephemeral address where funds are returned; this will be the sender of the fungible token packet data

• timeout_height — a chain height at which the transfer expires

• timeout_time — a timestamp at which the transfer expires

• source_channel — the IBC channel used for the withdrawal

Ics20Withdrawal::check_stateless verifies that the timeout_time is not zero.

Ics20Withdrawal::check_stateful verifies that

• the source channel exists and is not closed.

• there is a connection and nonfrozen client for the channel.

• the latest height of the receiving chain is less than the timeout_height.

Ics20Withdrawal::execute does two different things depending on whether the funds being transferred are local to Penumbra or if they were originally transferred in from an external chain. In the case where Penumbra is the source, the total ICS-20 balance for the specified asset is increased by the transfer amount and the total supply is unchanged (see Finding ref↗). In the external case, the total ICS-20 balance for the specified asset is decreased by the transfer amount and the total token supply for the asset is decreased by the same. Then the packet is sent to the destination chain.