@Override
  public @NotNull String asString() {
    assert myData.length > 0 : "bad length Hash.data";
    byte even = myData[0];
    StringBuilder sb = new StringBuilder();
    for (int i = 1; i < myData.length; i++) {
      int k1 = (myData[i] + 128) / 16;
      int k2 = (myData[i] + 128) % 16;
      char c1 = Character.forDigit(k1, 16);
      char c2 = Character.forDigit(k2, 16);
      if (i == myData.length - 1 && even == 1) {
        sb.append(c2);
      }
      else {
        sb.append(c1).append(c2);
      }
    }
    return sb.toString();
  }
@Override
  public @NotNull String asString()