<P>In view of a potentially high number of access requests to, and downloads of, their works or other subject matter, rightholders should be allowed to apply measures when there is a risk that the security and integrity of their systems or databases could be jeopardised. Such measures could, for example, be used to ensure that only persons having lawful access to their data can access them, including through IP address validation or user authentication. Those measures should remain proportionate to the risks involved, and should not exceed what is necessary to pursue the objective of ensuring the security and integrity of the system and should not undermine the effective application of the exception.</P>