 Rather than sending a plain text control word from the smart card to the receiver's microprocessor, which can be intercepted, the decrypted ECM will in fact be an encrypted control word, which can only be decrypted by a legitimate, non card sharing capable, receiver.A simpler method, used by several providers, is to simply increase the frequency of control word changes.With changes occurring as frequently as once every few seconds, extra stress is put onto the smart card sharing system, meaning that clients may be frustrated by short, frequent, missed viewing periods.