Our privacy is violated when people improperly come to know private things about us. Note, however, that all the harms that violation of privacy causes can be equally had without a violation of privacy. For instance, suppose that Sally the clever hacker breaks into my computer and figures out my credit card number while Jim the inept hacker tries to break into my computer and extract a credit card number, but due to a bug in his hacking script he never gets into my computer, but his hacking software reports a random number to him as my credit card numbers. If the random number happens by chance to match my credit card number, I am equally exposed to harms from Jim as from Sally. Yet only Sally has actually violated my privacy.
So I am not harmed by Sally's knowing my credit card number as such. Rather, I am harmed by Sally's (and Jim's) having a correct belief as to my credit card number.
In fact, in the case of some violations of privacy, it's the belief, not even the correctness of the belief, that harms me. If someone I thought to be a friend has communicated to people that I confessed to an embarrassing moral failure, my reputation is equally harmed just as much when the supposed friend is lying and I never committed the failure as when my supposed friend has violated my privacy. Typically it is easier to remove the harm when the belief about one is false, namely by presenting evidence as to its falsity, but even that is only typically true.
And in the credit card case, while correctness matters, the belief does not. If Jim orders expensive goods with a number that he does not believe to be a credit card number, simply on the off-chance that it might be one, and that number happens to be a valid credit card number, I am equally inconvenienced when that number is mine as in the case where he believed it to be my number.
All this suggests that a violation of privacy—people's coming to know private information about us—is not as such harmful. But the above cases neglect intrinsic harms. Take the case of the moral failure. While a false belief about my secret moral failures seems no less harmful to my reputation than a true belief, people's having true beliefs, and especially their having knowledge (if they just suspect and don't know, then that's a comfort), of my secret moral failures would be much more mortifying. Likewise, it seems one is intrinsically harmed if a voyeur installs a camera which transmits pictures of one getting dressed, but one does not suffer similar harm if the camera is defective and sends back random pixels which by chance look just like the real pictures would have.
So there can be a harm from loss of privacy as such. But it depends on the case. In the credit card number case, there is no intrinsic harm in the loss of privacy. Were there no chance of there being thieves, one could emblazon one's credit card numbers on one's T-shirt. In those cases, the violator's gaining knowledge is no worse than the violator's gaining a true belief. In the cases of shameful misdeeds there is typically an intrinsic harm and an instrumental harm from the violation of privacy. For the instrumental harm, it doesn't matter that the violator knows, or even that the violator's belief is true. But for the intrinsic harm, it does matter. In the case of bodily privacy, there is an intrinsic harm but there need not be any instrumental harm.
The case of instrumental harm is very puzzling. After all, isn't knowledge a good? How could someone's knowing something about me not be intrinsically good? But of course we need to distinguish subjects of goods. It is perhaps intrinsically good for the knower to know this thing about me (though perhaps instrumentally bad, say if it harms relationships). But perhaps it is not intrinsically good for me to have it known about me.
Even so, it's puzzling how knowledge can intrinsically harm the person known.
Perhaps our emotions and intuitions are misleading. I am more mortified if some embarrassing moral failure is known of me than if it is falsely believed of me. But perhaps I am simply confusing the fact that typically false beliefs are easier to refute than knowledge. So maybe it really is just harm to my reputation that is at issue?
Here is a hypothesis. Knowledge of people's past moral failures tends to be misleading information as it tends to lead people to think that the person lacks the dignity of someone in the image and likeness of God. Maybe it's worse when knowledge of one misleads people into seeing one as lacking dignity, just as it's worse when one's sins cause a harm to another than when the harm happens for some unrelated cause.
On the other hand, in heaven perhaps all secrets will be known, but moral failures will no longer mislead the knower into thinking that one lacks dignity. On the contrary, moral failures will be connected with the glory of God who gives the grace to overcome the moral failures and the failures will themselves be evidence of the person's dignity (since only a being with this kind of dignity is capable of sin). If people saw our failures in the perfectly right light, there would be no harm from loss of privacy. If this hypothesis is right, then the loss of privacy with respect to moral failures is not intrinsically harmful.
Bodily privacy is, perhaps, a similar matter. Rather than being evidence of the dignity of a child of God, in our fallen condition one can be led by the sight of a person's body to objectify or otherwise dehumanize the person. And maybe it is worse when one's body, rather than random pixels, is the cause of this unfortunate state of affairs.
I don't really know. All this is puzzling.