class ModulusFinder {

  public static BigInteger findSuitableModulus(int modBitLength) {
    if (modBitLength % 8 != 0) {
      throw new IllegalArgumentException("Bit length must be divisible by 8");
    }
    if (precomputed.containsKey(modBitLength)) {
      return precomputed.get(modBitLength);
    } else {
      return compute(modBitLength);
    }
  }

  private  ModulusFinder();

}