* SHA-1 (160 hash bits) hash function and a {@link SecretKeySpec} created from the given byte
   * array and the SHA-1 algorithm.
   *
   * @param key the key material of the secret key
   * @since 20.0
   */
  public static HashFunction hmacSha1(byte[] key) {
    return hmacSha1(new SecretKeySpec(checkNotNull(key), "HmacSHA1"));
  }

  /**