Function testDecapsulateKey

test/parallel/test-webcrypto-encap-decap-ml-kem.js:138–228

({ name, publicKeyPem, privateKeyPem, results })

}

async function testDecapsulateKey({ name, publicKeyPem, privateKeyPem, results }) {
  const [
    publicKey,
    privateKey,
    noDecapsulatePrivateKey,
  ] = await Promise.all([
    crypto.createPublicKey(publicKeyPem)
      .toCryptoKey(name, false, ['encapsulateKey']),
    crypto.createPrivateKey(privateKeyPem)
      .toCryptoKey(name, false, ['decapsulateKey']),
    crypto.createPrivateKey(privateKeyPem)
      .toCryptoKey(name, false, ['decapsulateBits']),
  ]);

  // Test successful round-trip: encapsulate then decapsulate
  const encapsulated = await subtle.encapsulateKey(
    { name },
    publicKey,
    'HKDF',
    false,
    ['deriveBits']
  );

  const decapsulatedKey = await subtle.decapsulateKey(
    { name },
    privateKey,
    encapsulated.ciphertext,
    'HKDF',
    false,
    ['deriveBits']
  );

  assert(decapsulatedKey instanceof CryptoKey);
  assert.strictEqual(decapsulatedKey.type, 'secret');
  assert.strictEqual(decapsulatedKey.algorithm.name, 'HKDF');
  assert.strictEqual(decapsulatedKey.extractable, false);
  assert.deepStrictEqual(decapsulatedKey.usages, ['deriveBits']);

  // Verify the keys are the same by using KeyObject.from() and comparing
  const originalKeyData = KeyObject.from(encapsulated.sharedKey).export();
  const decapsulatedKeyData = KeyObject.from(decapsulatedKey).export();
  assert(originalKeyData.equals(decapsulatedKeyData));

  const decapsulatedHmac = await subtle.decapsulateKey(
    { name },
    privateKey,
    encapsulated.ciphertext,
    { name: 'HMAC', hash: 'SHA-256', length: 255 },
    false,
    ['sign', 'verify']
  );
  assert.strictEqual(decapsulatedHmac.algorithm.name, 'HMAC');
  assert.strictEqual(decapsulatedHmac.algorithm.length, 255);
  assert.strictEqual(getCryptoKeyData(decapsulatedHmac).length, 32);
  assert.strictEqual(getCryptoKeyData(decapsulatedHmac)[31] & 0b00000001, 0);

  // Test with test vector ciphertext and expected shared key
  const vectorDecapsulatedKey = await subtle.decapsulateKey(