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Creating Accounts from Mnemonics⚓︎

BEGINNER

This tutorial shows how to create accounts for the NEM blockchain using a mnemonic phrase, also known simply as mnemonic.

This approach is commonly used by HD wallets to manage multiple accounts from a single seed.

Prerequisites⚓︎

If you have not done so already, start with Setting Up a Development Environment.

Full Code⚓︎

The following is the complete code listing for this tutorial. A detailed, step-by-step explanation follows in the next section.

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import os

from symbolchain.Bip32 import Bip32
from symbolchain.facade.NemFacade import NemFacade

# Initialize the facade for the testnet network
facade = NemFacade('testnet')

# Use an existing mnemonic if provided, otherwise generate a random one
bip32 = Bip32(NemFacade.BIP32_CURVE_NAME)
mnemonic = os.getenv('MNEMONIC')
if mnemonic:
    print('Loading mnemonic phrase from environment variable...')
else:
    print('Generating random mnemonic phrase...')
    mnemonic = bip32.random()
print(f'Mnemonic phrase: {mnemonic}')

# Load password from environment variable or use default
password = os.getenv('PASSWORD', 'correcthorsebatterystaple')
print(f'Password: {password}')

# Derive a root Bip32 node from the mnemonic and a password
root_node = bip32.from_mnemonic(mnemonic, password)

# Derive a child Bip32 node for the account at index 0
account_index = 0
child_node = root_node.derive_path(facade.bip32_path(account_index))

# Convert the Bip32 node to a signing key pair
key_pair = facade.bip32_node_to_key_pair(child_node)

# Derive the address from the public key
address = facade.network.public_key_to_address(key_pair.public_key)

# Output the account details
print(f'Address: {address}')
print(f'Public key: {key_pair.public_key}')
print(f'Private key: {key_pair.private_key}')

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import { Bip32 } from 'symbol-sdk';
import { NemFacade } from 'symbol-sdk/nem';
import process from 'process';

// Initialize the facade for the testnet network
const facade = new NemFacade('testnet');

// Use an existing mnemonic if provided, otherwise generate a random one
const bip32 = new Bip32(NemFacade.BIP32_CURVE_NAME);
let mnemonic = process.env.MNEMONIC;
if (mnemonic) {
    console.log('Loading mnemonic phrase from environment variable...');
} else {
    console.log('Generating random mnemonic phrase...');
    mnemonic = bip32.random();
}
console.log('Mnemonic phrase:', mnemonic);

// Load password from environment variable or use default
const password = process.env.PASSWORD || 'correcthorsebatterystaple';
console.log('Password:', password);

// Derive a root Bip32 node from the mnemonic and a password
const rootNode = bip32.fromMnemonic(mnemonic, password);

// Derive a child Bip32 node for the account at index 0
const accountIndex = 0;
const childNode = rootNode.derivePath(facade.bip32Path(accountIndex));

// Convert the Bip32 node to a signing key pair
const keyPair = NemFacade.bip32NodeToKeyPair(childNode);

// Derive the address from the public key
const address = facade.network.publicKeyToAddress(keyPair.publicKey);

// Output the account details
console.log('Address:', address.toString());
console.log('Public key:', keyPair.publicKey.toString());
console.log('Private key:', keyPair.privateKey.toString());

Download source

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//JAVA 21+
//DEPS org.symbol:symbol-sdk:3.3.3

import org.symbol.sdk.Bip32;
import org.symbol.sdk.CryptoTypes;
import org.symbol.sdk.facade.NemFacade;
import org.symbol.sdk.nem.Address;
import org.symbol.sdk.nem.KeyPair;

public final class CreateFromMnemonic {
    // Initialize the facade for the testnet network
    private final NemFacade facade = new NemFacade("testnet");


    public static void main(final String[] args) {
        new CreateFromMnemonic().run();
    }

    private void run() {
        // Use an existing mnemonic if provided,
        // otherwise generate a random one.
        final Bip32 bip32 = new Bip32(NemFacade.BIP32_CURVE_NAME);
        String mnemonic = System.getenv("MNEMONIC");
        if (null != mnemonic) {
            System.out.println(
                "Loading mnemonic phrase from environment variable...");
        } else {
            System.out.println("Generating random mnemonic phrase...");
            mnemonic = bip32.random();
        }
        System.out.printf("Mnemonic phrase: %s%n", mnemonic);

        // Load password from environment variable or use default
        final String password = System.getenv().getOrDefault(
            "PASSWORD", "correcthorsebatterystaple");
        System.out.printf("Password: %s%n", password);

        // Derive a root Bip32 node from the mnemonic and a password
        final Bip32.Bip32Node rootNode = bip32.fromMnemonic(
            mnemonic, password);

        // Derive a child Bip32 node for the account at index 0
        final int accountIndex = 0;
        final Bip32.Bip32Node childNode = rootNode.derivePath(
            facade.bip32Path(accountIndex));

        // Convert the Bip32 node to a signing key pair
        final KeyPair keyPair = NemFacade.bip32NodeToKeyPair(childNode);

        // Derive the address from the public key
        final CryptoTypes.PublicKey publicKey = keyPair.getPublicKey();
        final Address address = facade.network.publicKeyToAddress(
            publicKey);

        // Output the account details
        System.out.printf("Address: %s%n", address);
        System.out.printf("Public key: %s%n", publicKey);
        System.out.printf("Private key: %s%n",
            keyPair.getPrivateKey());
    }
}

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Code Explanation⚓︎

Initializing the Facade⚓︎

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# Initialize the facade for the testnet network
facade = NemFacade('testnet')

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// Initialize the facade for the testnet network
const facade = new NemFacade('testnet');

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    // Initialize the facade for the testnet network
    private final NemFacade facade = new NemFacade("testnet");

The provides access to NEM's cryptographic operations and network utilities. It is initialized with a network name (testnet or mainnet) to ensure that network-specific values, such as addresses, are generated correctly.

Defining a Mnemonic⚓︎

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# Use an existing mnemonic if provided, otherwise generate a random one
bip32 = Bip32(NemFacade.BIP32_CURVE_NAME)
mnemonic = os.getenv('MNEMONIC')
if mnemonic:
    print('Loading mnemonic phrase from environment variable...')
else:
    print('Generating random mnemonic phrase...')
    mnemonic = bip32.random()
print(f'Mnemonic phrase: {mnemonic}')

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// Use an existing mnemonic if provided, otherwise generate a random one
const bip32 = new Bip32(NemFacade.BIP32_CURVE_NAME);
let mnemonic = process.env.MNEMONIC;
if (mnemonic) {
    console.log('Loading mnemonic phrase from environment variable...');
} else {
    console.log('Generating random mnemonic phrase...');
    mnemonic = bip32.random();
}
console.log('Mnemonic phrase:', mnemonic);

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        // Use an existing mnemonic if provided,
        // otherwise generate a random one.
        final Bip32 bip32 = new Bip32(NemFacade.BIP32_CURVE_NAME);
        String mnemonic = System.getenv("MNEMONIC");
        if (null != mnemonic) {
            System.out.println(
                "Loading mnemonic phrase from environment variable...");
        } else {
            System.out.println("Generating random mnemonic phrase...");
            mnemonic = bip32.random();
        }
        System.out.printf("Mnemonic phrase: %s%n", mnemonic);

The example checks for an existing mnemonic in the MNEMONIC environment variable. If the variable is set, the mnemonic is loaded from it. Otherwise, a new random mnemonic is generated using .

NEM uses the BIP39 standard, which represents mnemonics as 24 English words selected from a standardized word list. These words encode the entropy (randomness) used to create all derived private keys.

Store your mnemonic phrase securely

The mnemonic phrase can be used to regenerate all derived accounts and private keys. Anyone with access to it can control your accounts, and losing it means losing access permanently.

Never share your mnemonic with anyone, and always store it in a secure location.

Deriving the Root Node⚓︎

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# Load password from environment variable or use default
password = os.getenv('PASSWORD', 'correcthorsebatterystaple')
print(f'Password: {password}')

# Derive a root Bip32 node from the mnemonic and a password
root_node = bip32.from_mnemonic(mnemonic, password)

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// Load password from environment variable or use default
const password = process.env.PASSWORD || 'correcthorsebatterystaple';
console.log('Password:', password);

// Derive a root Bip32 node from the mnemonic and a password
const rootNode = bip32.fromMnemonic(mnemonic, password);

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        // Load password from environment variable or use default
        final String password = System.getenv().getOrDefault(
            "PASSWORD", "correcthorsebatterystaple");
        System.out.printf("Password: %s%n", password);

        // Derive a root Bip32 node from the mnemonic and a password
        final Bip32.Bip32Node rootNode = bip32.fromMnemonic(
            mnemonic, password);

After defining the mnemonic, converts the mnemonic and a password into a root node, which serves as the starting point for deriving child accounts.

The password (sometimes called a "25th word") is an optional string that extends the mnemonic seed. It can be left empty or set to any value. When used, it adds another layer of security. Different passwords with the same mnemonic produce completely different accounts.

Password security

The password is part of the account derivation. Both the mnemonic and password are required to regenerate the accounts. If you lose either one, you lose access to all derived accounts.

In this example, the password is loaded from the PASSWORD environment variable. If not set, the snippet uses a default one.

Deriving the Child Account⚓︎

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# Derive a child Bip32 node for the account at index 0
account_index = 0
child_node = root_node.derive_path(facade.bip32_path(account_index))

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// Derive a child Bip32 node for the account at index 0
const accountIndex = 0;
const childNode = rootNode.derivePath(facade.bip32Path(accountIndex));

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        // Derive a child Bip32 node for the account at index 0
        final int accountIndex = 0;
        final Bip32.Bip32Node childNode = rootNode.derivePath(
            facade.bip32Path(accountIndex));

The root node can generate multiple accounts, each with its own unique keys and address. This allows a single mnemonic to manage many accounts while keeping them cryptographically isolated.

Deriving an account requires specifying an account index. generates the derivation path (a standardized string that specifies which account to derive) for that index, and follows that path to create the account.

In this example, the account at index 0 is derived. Additional accounts can be derived by using different indices (e.g., 1, 2, 3, ...). Each index produces a completely different account.

Creating the Account⚓︎

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# Convert the Bip32 node to a signing key pair
key_pair = facade.bip32_node_to_key_pair(child_node)

# Derive the address from the public key
address = facade.network.public_key_to_address(key_pair.public_key)

# Output the account details
print(f'Address: {address}')
print(f'Public key: {key_pair.public_key}')
print(f'Private key: {key_pair.private_key}')

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// Convert the Bip32 node to a signing key pair
const keyPair = NemFacade.bip32NodeToKeyPair(childNode);

// Derive the address from the public key
const address = facade.network.publicKeyToAddress(keyPair.publicKey);

// Output the account details
console.log('Address:', address.toString());
console.log('Public key:', keyPair.publicKey.toString());
console.log('Private key:', keyPair.privateKey.toString());

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        // Convert the Bip32 node to a signing key pair
        final KeyPair keyPair = NemFacade.bip32NodeToKeyPair(childNode);

        // Derive the address from the public key
        final CryptoTypes.PublicKey publicKey = keyPair.getPublicKey();
        final Address address = facade.network.publicKeyToAddress(
            publicKey);

        // Output the account details
        System.out.printf("Address: %s%n", address);
        System.out.printf("Public key: %s%n", publicKey);
        System.out.printf("Private key: %s%n",
            keyPair.getPrivateKey());

Once the child node is derived, it is converted into a usable key pair and address.

  1. Key pair creation: extracts the private key and public key from the child node. The private key must remain secret, while the public key can be safely shared.

  2. Address derivation: converts the public key into an address, a shorter, human-readable, network-specific identifier for the account.

Output⚓︎

The output shown below corresponds to a typical run of the program.

Generating random mnemonic phrase...
Mnemonic phrase: hamster diagram private dutch cause delay private meat slide toddler razor book happy fancy gospel tennis maple dilemma loan word shrug inflict delay *****
Password: correcthorsebatterystaple
Address: TBONKWCOWBZYZB2I5JD3LSDBQVBYHB757VN3SKPP
Public key: 462EE976890916E54FA825D26BDD0235F5EB5B6A143C199AB0AE5EE9328E08CE
Private key: 0000000000000000000000000000000000000000000000000000000000000000

Each time the code runs without environment variables, it generates a different random mnemonic and account. If the same mnemonic and password are provided, the same account is always derived for the given account index.

Conclusion⚓︎

This tutorial showed how to:

Step Related documentation
Create a random mnemonic
Derive an account from a mnemonic , , and
Get the key pair of the account ,