}

  /** Returns a hash function implementing the SHA-512 algorithm (512 hash bits). */
  public static HashFunction sha512() {
    return Sha512Holder.SHA_512;
  }

  private static class Sha512Holder {
    static final HashFunction SHA_512 =
        new MessageDigestHashFunction("SHA-512", "Hashing.sha512()");
  }

  /**

    public int hashCode() {
      return alphabet.hashCode() ^ Objects.hashCode(paddingChar);
    }
  }

  private static final class Base16Encoding extends StandardBaseEncoding {
    final char[] encoding = new char[512];

    Base16Encoding(String name, String alphabetChars) {
      this(new Alphabet(name, alphabetChars.toCharArray()));
    }

    private Base16Encoding(Alphabet alphabet) {
      super(alphabet, null);