Use Web Crypto API to create public and private key pairs and convert them to strings

js-public-private-key-generation.js

// Generated by ChatGPT: https://chat.openai.com/share/eef660d9-eaf2-494e-8175-54290254c73f

// Function to generate a key pair
async function generateKeyPair() {
  try {
    const keyPair = await window.crypto.subtle.generateKey(
      {
        name: 'RSA-OAEP',
        modulusLength: 2048,
        publicExponent: new Uint8Array([0x01, 0x00, 0x01]),
        hash: 'SHA-256',
      },
      true,
      ['encrypt', 'decrypt']
    );

    return keyPair;
  } catch (error) {
    console.error('Key generation error:', error);
  }
}

// Function to export key as a PEM string
async function exportKeyAsPEM(key, type) {
  try {
    const exportedKey = await window.crypto.subtle.exportKey(type === 'PUBLIC' ? 'spki' : 'pkcs8', type === 'PUBLIC' ? key.publicKey : key.privateKey);
    const exportedAsString = arrayBufferToBase64(exportedKey);

    const pemString = `-----BEGIN ${type} KEY-----\n${exportedAsString}\n-----END ${type} KEY-----\n`;

    return pemString;
  } catch (error) {
    console.error('Key export error:', error);
  }
}

// Function to convert ArrayBuffer to Base64
function arrayBufferToBase64(buffer) {
  const binary = String.fromCharCode.apply(null, new Uint8Array(buffer));
  return btoa(binary);
}

// Example usage
(async () => {
  const keyPair = await generateKeyPair();

  const publicKeyPEM = await exportKeyAsPEM(keyPair, 'PUBLIC');
  const privateKeyPEM = await exportKeyAsPEM(keyPair, 'PRIVATE');

  console.log('Public Key (PEM):', publicKeyPEM);
  console.log('Private Key (PEM):', privateKeyPEM);
})();