Hashing.hmacSha1(keyData).toString());

    assertEquals(
        "Hashing.hmacSha256(Key[algorithm=HmacSHA256, format=RAW])",
        Hashing.hmacSha256(SHA256_KEY).toString());
    assertEquals(
        "Hashing.hmacSha256(Key[algorithm=HmacSHA256, format=RAW])",
        Hashing.hmacSha256(keyData).toString());

    assertEquals(
        "Hashing.hmacSha512(Key[algorithm=HmacSHA512, format=RAW])",

   * @throws IllegalArgumentException if the given key is inappropriate for initializing this MAC
   * @since 20.0
   */
  public static HashFunction hmacSha256(Key key) {
    return new MacHashFunction("HmacSHA256", key, hmacToString("hmacSha256", key));
  }

  /**
   * Returns a hash function implementing the Message Authentication Code (MAC) algorithm, using the