When you say, "I have nothing to hide" it means "I don’t have this right". It means person under surveillance must justify the privacy, not those who are invading privacy.
If individuals have privacy rights, then invoking "nothing to hide" is irrelevant.
“How can you say that when you cannot imagine everything ‘they’ might be looking for? What if your faith, sexuality, technology, ideas or beliefs have become a target? Times change, so too do the things we have that we might need to hide”.
If someone doesn't care about his own privacy (but avoids endangering others' privacy when sharing information about himself), then that's his personal decision. One can list some of the possible but unlikely negative consequences that the person might not have thought of, but they aren't very strong counterarguments.
If the statement means "violating everyone's privacy is ok because I've got nothing to hide", then the counterargument is that some people legitimately have something to hide.
Lawyer and professor, Daniel Solove, wrote an essay called "'I've Got Nothing To Hide' and Other Misunderstandings Of Privacy" back in 2007 for the San Diego Law Review. Even though it's a bit long, I found his arguments very sound and logical.
http://scholarship.law.gwu.edu/cgi/viewcontent.cgi?article=1...
If individuals have privacy rights, then invoking "nothing to hide" is irrelevant.