web-crypto-ecdh.js

// Generated by ChatGPT: https://chat.openai.com/share/6c78c3f4-213d-48e6-9f79-b85ef3a7adc7

// Helper functions for converting between ArrayBuffer and base64
function arrayBufferToBase64(buffer) {
  const bytes = new Uint8Array(buffer);
  return btoa(String.fromCharCode.apply(null, bytes));
}

function base64ToArrayBuffer(base64) {
  const binaryString = atob(base64);
  const bytes = new Uint8Array(binaryString.length);
  for (let i = 0; i < binaryString.length; i++) {
    bytes[i] = binaryString.charCodeAt(i);
  }
  return bytes.buffer;
}

async function generateAndImportKeys() {
  try {
    // Generate an ECDH key pair
    const keyPair = await crypto.subtle.generateKey(
      {
        name: "ECDH",
        namedCurve: "P-256",
      },
      true, // Whether the key is extractable (private key)
      ["deriveKey", "deriveBits"] // Key usages
    );

    // Convert public key to string
    const publicKeyBuffer = await crypto.subtle.exportKey("spki", keyPair.publicKey);
    const publicKeyString = arrayBufferToBase64(publicKeyBuffer);
    console.log("Public Key String:", publicKeyString);

    // Convert private key to string
    const privateKeyBuffer = await crypto.subtle.exportKey("pkcs8", keyPair.privateKey);
    const privateKeyString = arrayBufferToBase64(privateKeyBuffer);
    console.log("Private Key String:", privateKeyString);

    // Convert the public key string back to CryptoKey
    const importedPublicKey = await crypto.subtle.importKey(
      "spki",
      base64ToArrayBuffer(publicKeyString),
      {
        name: "ECDH",
        namedCurve: "P-256",
      },
      false,
      []
    );
    console.log("Imported Public Key:", importedPublicKey);

    // Convert the private key string back to CryptoKey
    const importedPrivateKey = await crypto.subtle.importKey(
      "pkcs8",
      base64ToArrayBuffer(privateKeyString),
      {
        name: "ECDH",
        namedCurve: "P-256",
      },
      false,
      ["deriveKey", "deriveBits"]
    );
    console.log("Imported Private Key:", importedPrivateKey);
  } catch (error) {
    console.error("Error generating or importing keys:", error);
  }
}

// Call the async function
generateAndImportKeys();