public static byte[] ComputeAdditionalData(long fileLength)
{
long chunkCount = Utilities.RoundUp(fileLength, Constants.FileChunkSize);
byte[] ciphertextLength = BitConverter.GetBytes(chunkCount * Constants.TotalChunkLength);
return(Utilities.ConcatArrays(Constants.KryptorMagicBytes, Constants.EncryptionVersion, ciphertextLength));
}