/// <summary>
/// Check that the user corresponding to the given id is an authorized user.
/// </summary>
/// <param name="idOwner">Id of a user</param>
/// <seealso cref="checkAcl"/>
private void checkUser(IdentityReference idOwner)
{
log.Debug("Owner identity: " + idOwner);
if ((idOwner != idSystem) && (idOwner != idAdmin) && !idOwner.ToString().StartsWith("S-1-5-80"))
throw new UnauthorizedAccessException("Users should not be owner of the configuration file.");
}