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Exercise 1

Transfer BTC to Ethereum (as a wrapped asset) and back via Axelar Network CLI.

Level#

Intermediate

Disclaimer#

warning

Axelar Network is a work in progress. At no point in time should you transfer any real assets using Axelar. Only use testnet tokens that you're not afraid to lose. Axelar is not responsible for any assets lost, frozen, or unrecoverable in any state or condition. If you find a problem, please submit an issue to this repository following the template.

Prerequisites#

  • Complete all steps from Setup
  • Have a Ethereum wallet setup with MEW and have an Ethereum address funded with some Ether (You can also choose to use the Chrome plugin)

Useful links#

What you need#

Joining the Axelar testnet#

Follow the instructions in Setup to make sure your node is up to date and you received some test coins to your validator account.

Instructions to mint and burn tokens#

These instructions are a step by step guide to run commands to move an asset from a source to a destination chain and back. The assets are minted as wrapped ERC-20 assets on the destination chain. The commands are submitted to the Axelar Network that's responsible for (a) generating deposit/withdrawal addresses, (b) routing and finalizing transactions, and (c) minting/burning the corresponding assets.

To perform these tests, you'll need some test Bitcoins on the Bitcoin testnet, and a destination Ethereum address on the Ethereum Ropsten Testnet.

Mint ERC20 Bitcoin tokens on Ethereum#

  1. Create a deposit address on Bitcoin (to which you'll deposit coins later)
axelard tx bitcoin link ethereum {ethereum Ropsten dst addr} --from validator -y -b block-> returns deposit address

e.g.,

axelard tx bitcoin link ethereum 0xc1c0c8D2131cC866834C6382096EaDFEf1af2F52 --from validator -y -b block

Look for successfully linked {bitcoin deposit address} and {ethereum Ropsten dst addr}

  1. External: send a TEST BTC on Bitcoin testnet to the deposit address specific above, and wait for 6 confirmations (i.e. the transaction is 6 blocks deep in the Bitcoin chain).
  1. Confirm the Bitcoin outpoint
axelard tx bitcoin confirmTxOut "{txID:vout}" "{amount}btc" "{deposit address}" --from validator -y -b block

e.g.,

axelard tx bitcoin confirmTxOut 615df0b4d5053630d24bdd7661a13bea28af8bc1eb0e10068d39b4f4f9b6082d:0 0.00088btc tb1qlteveekr7u2qf8faa22gkde37epngsx9d7vgk98ujtzw77c27k7qk2qvup --from validator -y -b block

Wait for transaction to be confirmed (~10 Axelar blocks, ~50 secs). Eventually, you'll see something like this in the node terminal:

bitcoin outpoint confirmation result is

You can search it using docker logs -f axelar-core 2>&1 | grep -a -e outpoint.

  1. Trigger signing of the transfers to Ethereum
axelard tx evm sign-pending-transfers ethereum --from validator -y -b block-> returns commandID of signed tx-> wait for sign protocol to complete (~10 blocks)

Look for commandID and its value in the output: 

"key": "commandID","value": "d5e993e407ff399cf2770a1d42bc2baf5308f46632fcbe209318acb09776599f"

You can search it using docker logs -f axelar-core 2>&1 | grep -a -e command.

  1. Get the command data that needs to be sent in an Ethereum transaction in order to execute the mint
axelard q evm command ethereum {commandID}

e.g.,

axelard q evm command ethereum 28a523a4d5836df2cdc3af5beffc10ca946e62497d609521504462e043a38fdc

The command data will be displayed as output.

  1. Send the Ethereum transaction wrapping the command data to execute the mint

Open your Metamask wallet, go to Settings -> Advanced, then find Show HEX data and enable that option. This way you can send a data transaction directly with the Metamask wallet. Keep in mind not to transfer any tokens, you just need to input the data from the above commandID and send it to the Gateway smart contract (see Testnet Release). While doing this please make sure the gas price in Metamask is updated once you paste in the data.

Alternatively you can open your MEW wallet, and navigate to the "Send Transaction" page, with the advanced options open, too. Now, you need to send a transaction to the Gateway smart contract with 0 Ether, and with data field being the command data you retrieved in the previous step. Your screen should look similar to following and you can just send the transaction to execute and mint your tokens.

(Note that the "To Address" is the address of Axelar Gateway smart contract, which you can find here, and the "Add Data" field is the command data you got from the previous step)

You can now open Metamask, select "Assets" then "Add Token" then "Custom Token" and then paste the token contract address (see axelarate-community/TESTNET RELEASE.md and look for Ethereum token contract address field).

Burn ERC20 wrapped Bitcoin tokens and obtain native Satoshi#

To send wrapped Bitcoin back to Bitcoin, run the following commands:

  1. Create a deposit address on Ethereum
axelard tx evm link ethereum bitcoin {destination bitcoin addr} satoshi --from validator -y -b block-> returns deposit address

e.g.,

axelard tx evm link ethereum bitcoin tb1qg2z5jatp22zg7wyhpthhgwvn0un05mdwmqgjln satoshi --from validator -y -b block

Look for the Ethereum deposit address as the first output in this line (0x5CFE...):

"successfully linked {0x5CFEcE3b659e657E02e31d864ef0adE028a42a8E} and {tb1qq8wnre6rzctec9wycrl2dq00m3avravslahc8v}"
note

Make sure to link a Bitcoin address that is controlled by you, e.g. if you link it to an address controlled by Axelar your withdrawal will be considered a donation and added to the pool of funds

  1. External: send wrapped tokens to deposit address (e.g. with Metamask). You need to have some Ropsten testnet Ether on the address to send transactions. Wait for 30 Ethereum block confirmations. You can monitor the status of your deposit using the testnet explorer: https://ropsten.etherscan.io/

  2. Confirm the Ethereum transaction

axelard tx evm confirm-erc20-deposit ethereum {txID} {amount} {deposit addr} --from validator -y -b block

Here, amount should be specific in Satoshi. (For instance, 0.0001BTC = 10000) e.g.,

axelard tx evm confirm-erc20-deposit ethereum 0x01b00d7ed8f66d558e749daf377ca30ed45f747bbf64f2fd268a6d1ea84f916a 10000 0x5CFEcE3b659e657E02e31d864ef0adE028a42a8E --from validator -y -b block

Wait for transaction to be confirmed. Eventually, you'll see something like this in the node terminal:

Ethereum deposit confirmation result is {result}

You can search it using docker logs -f axelar-core 2>&1 | grep -a -e "deposit confirmation".

You're done! In the next step, a withdrawal must be signed and submitted to the Bitcoin network.

tip

In this release, we're triggering these commands about once a day. So come back in 24 hours, and check the balance on the Bitcoin testnet address to which you submitted the withdrawal.