Transferring assets over IBC

It is possible to make ibc transfers using the Namada cli with the command namadac ibc-transfer. The assumed pre-requisites are that a channel has been created and Hermes is running with the proper config on two nodes.

In order to conduct an IBC transfer using Namada's ibc-transfer command, we will need to know the base-dir and node of each instance (and other transfer parameters). base-dir is the base directory of each node, see base-dir for more information. node is the rpc_addr of the relayer. You can run

grep "rpc_addr" ${HERMES_CONFIG}

to find the address.

export BASE_DIR_A="${HERMES}/data/namada-a/.namada"
export LEDGER_ADDRESS_A="$(grep "rpc_address" ${BASE_DIR_A}/${CHAIN_A_ID}/setup/validator-0/.namada/${CHAIN_A_ID}/config.toml)"

The channel ID for this chain will depend on the order in which one created the channel. Since we have only opened one channel, the channel-id is channel-0, but as more are created, these increase by index incremented by 1. The channel-id should be communicated by the relayer.

Assuming that the open channel is channel-0, you can save it in an environment variable by running

export CHANNEL_ID="channel-0"

The inter-blockchain transfers from Chain A can be achieved by

namadac --base-dir ${BASE_DIR_A}
    ibc-transfer \
        --amount ${AMOUNT} \
        --source ${SOURCE_ALIAS} \
        --receiver ${RECEIVER_RAW_ADDRESS} \
        --token ${TOKEN_ALIAS} \
        --channel-id ${CHANNEL_ID} \
        --node ${LEDGER_ADDRESS_A}

Where the above variables in ${VARIABLE} must be substituted with appropriate values. The raw address of the receiver can be found by namadaw --base-dir ${BASE_DIR_B} address find --alias ${RECEIVER}.

E.g.

namadac --base-dir ${BASE_DIR_A}
    ibc-transfer \
    --amount 100 \
    --source albert \
    --receiver atest1d9khqw36g56nqwpkgezrvvejg3p5xv2z8y6nydehxprygvp5g4znj3phxfpyv3pcgcunws2x0wwa76 \
    --token nam \
    --channel-id channel-0 \
    --node http://127.0.0.1:27657

Once the transaction has been submitted, a relayer will need to relay the packet to the other chain. This is done automatically by the relayer running Hermes. If the packet is never successfully relayed, the funds are returned to the sender after a timeout. See more information in the specs (opens in a new tab).

Transferring assets back from Cosmos-SDK based chains

When a transfer has been made to a Cosmos-SDK based chain, the ibc transfer is conducted as above. However, when transferring back from the cosmos-based chain, clearly the namadac ibc-transfer command will not work. Instead, you want to use gaiad (opens in a new tab).

gaiad tx ibc-transfer transfer transfer ${CHANNEL_ID} ${RECEIVER_RAW_ADDRESS} ${AMOUNT}${IBC_TOKEN_ADDRESS} --from ${COSMOS_ALIAS} --node ${COSMOS_RPC_ENDPOINT} --fees 5000uatom

for example:

gaiad tx ibc-transfer transfer transfer channel-0 atest1d9khqw368qcyx3jxxu6njs2yxs6y2sjyxdzy2d338pp5yd35g9zrv334gceng3z9gvmryv2pfdddt4 10ibc/281545A262215A2D7041CE1B518DD4754EC7097A1C937BE9D9AB6F1F11B452DD --from my-cosmos-address --node https://rpc.sentry-01.theta-testnet.polypore.xyz:443 --fees 5000uatom

Shielding transfer

Before namadac ibc-transfer, you need to generate a proof of the following IBC transfer for the shielding transfer to the destination Namada. The command namadac ibc-gen-shielded generates the proof and outputs a file including required data. In this case, Chain B is the destination chain.

namadac --base-dir ${BASE_DIR_B} ibc-gen-shielded \
  --output-folder-path ${OUTPUT_PATH} \
  --target ${payment_addr_b} \
  --token apfel \
  --amount 100 \
  --port-id transfer \
  --channel-id channel-0 \
  --node ${LEDGER_ADDRESS_B}

Then, you can send the token from the source chain by setting the proof in the ICS-20 packet's memo field. The following example is to send tokens from the source Namada (Chain A). The ${memo_path} should be the file path created by namadac ibc-gen-shielded on the destination chain.

namadac --base-dir ${BASE_DIR_A} ibc-transfer \
  --source ${spending_key_a} \
  --receiver ${payment_addr_b} \
  --token apfel \
  --amount 100 \
  --channel-id channel-0 \
  --memo-path ${memo_path} \
  --node ${LEDGER_ADDRESS_A}

When the source chain is a Cosmos-SDK based chain, the memo should be set as string with --memo option.

memo=$(cat ${memo_path})
gaiad tx ibc-transfer transfer \
  ${CHANNEL_ID} \
  ${RECEIVER_PAYMENT_ADDRESS} \
  ${AMOUNT}${IBC_TOKEN_ADDRESS} \
  --from ${COSMOS_ALIAS} \
  --memo ${memo} \
  --node ${COSMOS_RPC_ENDPOINT} \
  --fees 5000uatom

You can do unshielding transfers over IBC without generating a proof.

namadac --base-dir ${BASE_DIR_A} ibc-transfer \
  --source ${spending_key_a} \
  --receiver ${RECEIVER_RAW_ADDRESS} \
  --token nam \
  --amount 100 \
  --channel-id channel-0 \
  --node ${LEDGER_ADDRESS_A}