js-public-private-key-generation-with-private-key-decryption.js

// Written by ChatGPT: https://chat.openai.com/share/5a3241a3-d4ab-4d85-96c5-9aafdff8e483

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

  return keyPair;
}

// Function to encrypt a string with the public key
async function encryptString(publicKey, plaintext) {
  const encodedText = new TextEncoder().encode(plaintext);
  const encryptedData = await crypto.subtle.encrypt(
    {
      name: 'RSA-OAEP',
    },
    publicKey,
    encodedText
  );

  return encryptedData;
}

// Function to decrypt data with the private key
async function decryptString(privateKey, encryptedData) {
  const decryptedArrayBuffer = await crypto.subtle.decrypt(
    {
      name: 'RSA-OAEP',
    },
    privateKey,
    encryptedData
  );

  const decryptedText = new TextDecoder().decode(decryptedArrayBuffer);
  return decryptedText;
}

// Example usage
(async () => {
  try {
    // Generate key pair
    const keyPair = await generateKeyPair();

    // Get public and private keys
    const publicKey = keyPair.publicKey;
    const privateKey = keyPair.privateKey;

    // Text to encrypt
    const plaintext = 'Hello, Web Crypto API!';

    // Encrypt using the public key
    const encryptedData = await encryptString(publicKey, plaintext);

    // Decrypt using the private key
    const decryptedText = await decryptString(privateKey, encryptedData);

    console.log('Original Text:', plaintext);
    console.log('Encrypted Data:', new Uint8Array(encryptedData));
    console.log('Decrypted Text:', decryptedText);
  } catch (error) {
    console.error('Error:', error);
  }
})();