wasmd/docs/ledger.md

Ledger Nano Support

Using a hardware wallet to store your keys greatly improves the security of your crypto assets. The Ledger device acts as an enclave of the seed and private keys, and the process of signing transaction takes place within it. No private information ever leaves the Ledger device. The following is a short tutorial on using the Cosmos Ledger app with the Gaia CLI or the Lunie.io web wallet.

At the core of a Ledger device there is a mnemonic seed phrase that is used to generate private keys. This phrase is generated when you initialize you Ledger. The mnemonic is compatible with Cosmos and can be used to seed new accounts.

::: danger Do not lose or share your 24 words with anyone. To prevent theft or loss of funds, it is best to keep multiple copies of your mnemonic stored in safe, secure places. If someone is able to gain access to your mnemonic, they will fully control the accounts associated with them. :::

Gaia CLI + Ledger Nano

The tool used to generate addresses and transactions on the Cosmos Hub network is gaiacli. Here is how to get started. If using a CLI tool is unfamiliar to you, scroll down and follow instructions for using the Lunie.io web wallet instead.

Before you Begin

• Install the Cosmos app onto your Ledger
• Install Golang
• Install Gaia

Verify that gaiacli is installed correctly with the following command

gaiacli version --long

➜ cosmos-sdk: 0.34.3
git commit: 67ab0b1e1d1e5b898c8cbdede35ad5196dba01b2
vendor hash: 0341b356ad7168074391ca7507f40b050e667722
build tags: netgo ledger
go version go1.11.5 darwin/amd64

Add your Ledger key

• Connect and unlock your Ledger device.
• Open the Cosmos app on your Ledger.
• Create an account in gaiacli from your ledger key.

::: tip Be sure to change the keyName parameter to be a meaningful name. The ledger flag tells gaiacli to use your Ledger to seed the account. :::

gaiacli keys add <keyName> --ledger

➜ NAME: TYPE: ADDRESS:     PUBKEY:
<keyName> ledger cosmos1... cosmospub1...

Cosmos uses HD Wallets. This means you can setup many accounts using the same Ledger seed. To create another account from your Ledger device, run;

gaiacli keys add <secondKeyName> --ledger

Confirm your address

Run this command to display your address on the device. Use the keyName you gave your ledger key. The -d flag is supported in version 1.5.0 and higher.

gaiacli keys show <keyName> -d

Confirm that the address displayed on the device matches that displayed when you added the key.

Connect to a full node

Next, you need to configure gaiacli with the URL of a Cosmos full node and the appropriate chain_id. In this example we connect to the public load balanced full node operated by Chorus One on the cosmoshub-2 chain. But you can point your gaiacli to any Cosmos full node. Be sure that the chain_id is set to the same chain as the full node.

gaiacli config node https://cosmos.chorus.one:26657
gaiacli config chain_id cosmoshub-2

Test your connection with a query such as:

`gaiacli query staking validators`

::: tip To run your own full node locally read more here.. :::

Sign a transaction

You are now ready to start signing and sending transactions. Send a transaction with gaiacli using the tx send command.

gaiacli tx send --help # to see all available options.

::: tip Be sure to unlock your device with the PIN and open the Cosmos app before trying to run these commands :::

Use the keyName you set for your Ledger key and gaia will connect with the Cosmos Ledger app to then sign your transaction.

gaiacli tx send <keyName> <destinationAddress> <amount><denomination>

When prompted with confirm transaction before signing, Answer Y.

Next you will be prompted to review and approve the transaction on your Ledger device. Be sure to inspect the transaction JSON displayed on the screen. You can scroll through each field and each message. Scroll down to read more about the data fields of a standard transaction object.

Now, you are all set to start sending transactions on the network.

Receive funds

To receive funds to the Cosmos account on your Ledger device, retrieve the address for your Ledger account (the ones with TYPE ledger) with this command:

gaiacli keys list

➜ NAME: TYPE: ADDRESS:     PUBKEY:
<keyName> ledger cosmos1... cosmospub1...

Further documentation

Not sure what gaiacli can do? Simply run the command without arguments to output documentation for the commands in supports.

::: tip The gaiacli help commands are nested. So $ gaiacli will output docs for the top level commands (status, config, query, and tx). You can access documentation for sub commands with further help commands.

For example, to print the query commands:

gaiacli query --help

Or to print the tx (transaction) commands:

gaiacli tx --help

:::

Lunie.io

The Lunie web wallet supports signing with Ledger Nano S. Here is a short intro to using your Ledger with Lunie.io.

Connect your device

• Connect your Ledger device to your computer, unlock it with the PIN and open the Cosmos app.
• Open https://lunie.io in your web browser (latest version of Google Chrome preferred)
• Click “Sign in”.
• Choose “Sign in with Ledger Nano S”

Confirm your address

Run this command to display your address on the device. Use the keyName you gave your ledger key. The -d flag is supported in version 1.5.0 and higher.

gaiacli keys show <keyName> -d

Confirm that the address displayed on your Ledger matches that shown on Lunie.io before proceeding. Now you can use your Ledger key to sign transctions on Lunie.

To learn more about using Lunie, here is a tutorial on staking and delegating ATOMs using the Lunie web wallet.

The Cosmos Standard Transaction

Transactions in Cosmos embed the Standard Transaction type from the Cosmos SDK. The Ledger device displays a serialized JSON representation of this object for you to review before signing the transaction. Here are the fields and what they mean:

• chain-id: The chain to which you are broadcasting the tx, such as the gaia-13003 testnet or cosmoshub-2: mainnet.
• account_number: The global id of the sending account assigned when the account receives funds for the first time.
• sequence: The nonce for this account, incremented with each transaction.
• fee: JSON object describing the transaction fee, its gas amount and coin denomination
• memo: optional text field used in various ways to tag transactions.
• msgs_<index>/<field>: The array of messages included in the transaction. Double click to drill down into nested fields of the JSON.

Support

For further support, start by looking over the posts in our forum

Feel welcome to reach out in our Telegram channel to ask for help.

Here are a few relevant and helpful tutorials from the wonderful Cosmos community:

• Ztake - How to Redelegate Cosmos Atoms with the Lunie Web Wallet
• Cryptium Labs - How to store your ATOMS on your Ledger and delegate with the command line