Private Keys

To send transactions to a blockchain network, you need a private key to sign these transactions, and the private key should contain enough funds to cover the gas price for the transaction.

You can sign transactions with private keys you created outside SettleMint with e.g. MetaMask or other wallet solutions. SettleMint however provides an option to create and manage private keys within the platform.

When you deploy a blockchain node it contains a signing proxy that captures the eth_sendTransaction call, uses the appropriate key from the private key section to sign it, and sends it onwards to the blockchain node. You can use this proxy directly via the nodes JSON-RPC endpoints (https://eth.wiki/json-rpc/API) and via tools like Hardhat (https://hardhat.org/config/#json-rpc-based-networks) configured to use the "remote" default option for signing.

Create a private key

Platform UI

Navigate to your application, click Private keys in the left navigation, and then click Create a private key. This opens a form.

Follow these steps to create the private key:

1. Choose a private key type:

   • Accessible ECDSA P256: Standard Ethereum-style private keys with exposed mnemonic
   • HD ECDSA P256: Hierarchical Deterministic keys for advanced key management
   • HSM ECDSA P256: Hardware Security Module protected keys for maximum security

2. Choose a name for your private key

3. Select the nodes on which you want the key to be active

4. Click Confirm to create the key

SDK CLI

# Create Accessible ECDSA P256 key
settlemint platform create private-key accessible-ecdsa-p256 my-key \
  --application my-app \
  --blockchain-node node-123

# Create HD ECDSA P256 key
settlemint platform create private-key hd-ecdsa-p256 my-key \
  --application my-app

# Create HSM ECDSA P256 key
settlemint platform create private-key hsm-ecdsa-p256 my-key \
  --application my-app

SDK JS

import { createSettleMintClient } from '@settlemint/sdk-js';

const client = createSettleMintClient({
  accessToken: 'your_access_token',
  instance: 'https://console.settlemint.com'
});

// Create private key
const createKey = async () => {
  const result = await client.privateKey.create({
    name: "my-key",
    applicationUniqueName: "my-app",
    privateKeyType: "ACCESSIBLE_ECDSA_P256", // or "HD_ECDSA_P256" or "HSM_ECDSA_P256"
    blockchainNodeUniqueNames: ["node-123"] // optional
  });
  console.log('Private key created:', result);
};

Manage private keys

Platform UI

1. Navigate to your application's Private keys section
2. Click on a private key to:
   • View details and status
   • Manage node associations
   • Check balances
   • Fund the key

SDK CLI

# List all private keys
settlemint platform list private-keys --application <app-name>

# View specific key details
settlemint platform read private-key <private-key-unique-name>

# Restart a private key
settlemint platform restart private-key <private-key-unique-name>

SDK JS

// List private keys
const listKeys = async () => {
  const keys = await client.privateKey.list("your-app-name");
};

// Get key details
const getKey = async () => {
  const key = await client.privateKey.read("key-unique-name");
};

// Restart key
const restartKey = async () => {
  await client.privateKey.restart("key-unique-name");
};

Fund the private key

For networks that require gas to perform a transaction, your private key should contain enough funds to cover the gas price.

1. Click the private key in the overview to see detailed information
2. Open the Balances tab
3. Click Fund
4. Scan the QR code with your wallet/exchange to fund the key

Note

Ensure your private key has sufficient funds before attempting transactions on networks that require gas fees.