who millions of americans call and how long they talk. but if you don't want to take any chances, there is an app. for that. david lee miller with the good news. david lee? >> shepard, there are, in fact, more than a half a dozen apps available online such as see clift and silent circle that say they will protect your privacy. the next time you use your smart phone. they each encrypt the data from your phone making it difficult if not impossible for a third party to listen in or learn who you are calling. some of the companies say they are based outside the u.s. in order to being subject to u.s. privacy laws and subpoenas but add they will do the right thing if public safety is at risk. >> this is an app. to restore privacy rights to the average person. we are not here to help terrorists just to be very clear. so if a government comes to us and says we need help, you know, we will cooperate with them to the full extent that we can. >> most of the incryption services say once a call is finished all relevant data is destroyed.