The Edward Snowden controversy has highlighted how much presumed private data is actually on public wires, passing through public routers — effectively in the public domain.
The truth is, privacy in our modern society is misunderstood. In fact, true privacy is ephemeral. Thomas Jefferson probably died thinking that knowledge of his sexual relations with some of his slaves was going to die with him. How could he know that two centuries later, modern genetics showed exactly whom he was sleeping with and how many illegitimate descendants he fathered.
Similarly, protecting a file with extremely secure DES encryption means that today it is very hard to decrypt if you don't know the key. Yet the definition of “very hard” is continually evolving. What used to take a very long time to crack on a Digital Equipment PDP-11 years ago now might just take a few minutes on a modern multiprocessing super-computer. So, assuming Moore's Law continues, or even assuming computers just continue to get faster, any encryption you use today will someday be deciphered by future technology.
The physicality of a personal hard drive enabled private information to be destroyed or rendered unreadable. One could physically destroy it — hit it with a hammer. Storing data in the cloud changes all that. No matter how it is encrypted, one should assume that whatever is in that encrypted file will someday be revealed. It probably means that the future will be able to expose everything that was going on today, private or public, sensitive or meaningless.
One can argue that you can consciously delete a file and it will be gone forever. But now that we have redundancy and multiple backups and multiple local caches of data, a file can be in many places at once. Today data goes into my sent folder, and is silently backed up into my cloud Exchange server.
Future archeologists will love this transition to the cloud. Suddenly, the most intimate details of people's decisions and actions will be largely transparent to historians. Certainly Nixon never considered how recording every call and meeting could come back and bite him. Increasingly, every electronic communication you have will be recoverable in the future. And it won't just be the metadata the NSA has been mining over the past few years, as Snowden has shown us, but ultimately the encrypted content as well.
Things we consider secret will likely become available to future generations. Encryption only delays the inevitable. It may in fact call attention to a file that otherwise would be overlooked in plain sight. Future generations will be able to data-mine the past.
Don't get me wrong — I love the cloud. All my devices are working off the same database — I have one digital life instead of many slightly different ones. But it's rather unnerving to think that what you believe is secure now will not be so in 10 to 20 years. It's a fact that Jefferson, Nixon, and, now– Anthony Weiner– will have done well to consider.
Long term Privacy is an illusion.