Function unwrapKeyImpl

lib/internal/crypto/webcrypto.js:1093–1154

(
  format,
  wrappedKey,
  unwrappingKey,
  unwrapAlgorithm,
  unwrappedKeyAlgorithm,
  extractable,
  keyUsages)

}

function unwrapKeyImpl(
  format,
  wrappedKey,
  unwrappingKey,
  unwrapAlgorithm,
  unwrappedKeyAlgorithm,
  extractable,
  keyUsages) {
  const prefix = prepareSubtleMethod(this, 'unwrapKey', arguments.length, 7);
  let i = 0;
  format = convertSubtleArgument(prefix, 'KeyFormat', format, i++);
  wrappedKey = convertSubtleArgument(prefix, 'BufferSource', wrappedKey, i++);
  unwrappingKey = convertSubtleArgument(
    prefix, 'CryptoKey', unwrappingKey, i++);
  const algorithm = convertSubtleArgument(
    prefix, 'AlgorithmIdentifier', unwrapAlgorithm, i++);
  unwrappedKeyAlgorithm = convertSubtleArgument(
    prefix, 'AlgorithmIdentifier', unwrappedKeyAlgorithm, i++);
  extractable = convertSubtleArgument(prefix, 'boolean', extractable, i++);
  const usages = convertSubtleArgument(
    prefix, 'sequence<KeyUsage>', keyUsages, i++);

  let normalizedAlgorithm;
  try {
    normalizedAlgorithm = normalizeAlgorithm(algorithm, 'unwrapKey');
  } catch {
    normalizedAlgorithm = normalizeAlgorithm(algorithm, 'decrypt');
  }

  const normalizedKeyAlgorithm =
    normalizeAlgorithm(unwrappedKeyAlgorithm, 'importKey');

  if (normalizedAlgorithm.name !== getCryptoKeyAlgorithm(unwrappingKey).name)
    throw lazyDOMException('Key algorithm mismatch', 'InvalidAccessError');

  if (!hasCryptoKeyUsage(unwrappingKey, 'unwrapKey'))
    throw lazyDOMException(
      'Unable to use this key to unwrapKey', 'InvalidAccessError');

  const bytes = cipherOrWrap(
    kWebCryptoCipherDecrypt,
    normalizedAlgorithm,
    unwrappingKey,
    wrappedKey);

  return jobPromiseThen(bytes, (bytes) => {
    let keyData = bytes;
    if (format === 'jwk') {
      keyData = parseJwk(bytes);
    }

    return FunctionPrototypeCall(
      importKeySync,
      this,
      format,
      keyData,
      normalizedKeyAlgorithm,
      extractable,