On one hand we have the Utilitarianist view of security. If increased security results in "more good" than evil, it is inherently ethical and thus acceptable. In this view, the idea that a good person may be blackmailed is perfectly acceptable, as long as it exposes political malfeasance.
On the other hand there's the Kantian view. If you have to lie, it it hurts someone, or it wouldn't work if it applied to everyone, then it's unethical. This doesn't seem to work at all, because we have to allow lying (non-repudiation). But non-repudiation could prevent someone from being hurt. And applying it to everyone would allow for the least harm, rather than the most good.
In the end Utilitarianism usually reigns because it's easier. But it does ignore the edge cases, which we should consider. Perhaps the way forward is not to pick one or the other, but actually re-make the world to embrace the good and avoid the bad. Sadly, that's probably the most difficult choice of all; when's the last time we replaced a working standard just because it had crappy outcomes?