Creating a Private Key

To participate in a blockchain network, such as issuing transactions, you need to create a private key. This private key allows you to secure your account and perform transactions using your unique key.

In Nine Chronicles, the blockchain technology is powered by Libplanet. Through the Libplanet.Tools project, you can use the planet CLI to create a private key.

Installing the planet CLI

First, refer to the README documentation for Libplanet.Tools to install the planet CLI.

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This tutorial uses version 5.0.0 of the planet CLI.

Using planet key

Let’s create a private key using the planet key command. First, run the planet key command to see the list of managed keys.

planet key

You should see something like this:

Key ID                               Address                                   
------------------------------------ ------------------------------------------

Since no keys exist yet, the list is empty. Next, let’s check out the options available by running the planet key --help command.

planet key --help

You’ll see the following output:

Usage: planet key [command]
Usage: planet key [--path <String>] [--help]

List all private keys.

Commands:
  create      Create a new private key.
  remove      Remove a private key.
  import      Import a raw private key or Web3 Secret Storage.
  export      Export a raw private key (or public key).
  generate    Generate a raw private key without storing it.
  sign        Sign a message.
  derive      Derive public key and address from private key.

Options:
  --path <String>    Specify key store path to list.
  -h, --help         Show help message

Now, let’s use the planet key create command to generate a new private key.

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When creating a private key for actual use, make sure to use a strong passphrase.

planet key create

You’ll be prompted to enter a passphrase:

Passphrase: ***************
Retype passphrase: ***************
Key ID                               Address                                   
------------------------------------ ------------------------------------------
1fd94a3e-2273-489b-bd44-b62036e2c07d 0xb4179Ad0d7565A6EcFA70d2a0f727461039e0159

After entering a passphrase, a new private key is created. The key is represented by a Key ID and an Address within the planet CLI. Next, let’s export the private and public keys from this Key ID. Run planet key export --help to see the available options.

planet key export --help

You’ll see the following output:

Usage: planet key export [--passphrase <PASSPHRASE>] [--passphrase-file <FILE>] [--public-key] [--bytes] [--json] [--path <String>] [--help] key-id

Export a raw private key (or public key).

Arguments:
  0: key-id    A key UUID to export. (Required)

Options:
  -p, --passphrase <PASSPHRASE>    Take passphrase through this option instead of prompt.  Mutually exclusive with --passphrase-file option.
  --passphrase-file <FILE>         Read passphrase from the specified file instead of taking it through prompt.  Mutually exclusive with -p/--passphrase option.  For standard input, use a hyphen (`-').  For an actual file named a hyphen, prepend `./', i.e., `./-'.  Note that the trailing CR/LF is trimmed.
  -P, --public-key                 Export a public key instead of private key.
  -b, --bytes                      Print raw bytes instead of hexadecimal.  No trailing LF appended.
  --json                           Export a Web3 Secret Storage Formatted json
  --path <String>                  Path to key store to export from.
  -h, --help                       Show help message

Let’s retrieve the private key using the --passphrase option with the passphrase you previously entered.

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For demonstration purposes, we will expose the private key here, but never expose your private key in any other context.

planet key export 1fd94a3e-2273-489b-bd44-b62036e2c07d --passphrase=***************

The output will be:

9fe5f7c309495d284ca36b948fdeca0e65b21a019e2f8a03efd849df88fab102

Now, let’s export the public key using the --public-key option.

planet key export 1fd94a3e-2273-489b-bd44-b62036e2c07d --passphrase=*************** --public-key

The output will be:

033dafc7bf6d603578a8c51b04430b738aeeead8a012e1dcbd8c75cf18a625cf14

Here’s a summary of the key information we’ve generated:

Key ID: 1fd94a3e-2273-489b-bd44-b62036e2c07d
Private Key: 9fe5f7c309495d284ca36b948fdeca0e65b21a019e2f8a03efd849df88fab102
Public Key: 033dafc7bf6d603578a8c51b04430b738aeeead8a012e1dcbd8c75cf18a625cf14
Address: 0xb4179Ad0d7565A6EcFA70d2a0f727461039e0159

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Great work! You’ve just learned how to create and manage a private key using the planet CLI. Next, we’ll use this key to create a genesis block.