The forget the encryption key approach is clever.
No. Don't confuse symmetric with asymmetric (current public key) encryption. They aren't subject to the same potential attacks. Even with a theoretical fully scalable general purpose quantum computer, the best quantum attack vs a symmetric cypher is brute forcing with Grover's Algorithm, which provides a quadratic rather then exponential speed up. Ie., a n-bit key could be attacked in around 2^(n/2). This is trivially countered by doubling key length, a 256-bit key would still take 2^128 which would still be effectively impossible, and a 512-bit key would take 2^256. There is no future with any foreseen technology that would be able to brute force that, so when it comes to AES and the like using at least 256-bit keys it can be reasonably assumed that destroying the key means the data is lost (anything legacy running off 128-bit is reasonable to watch out for though, 2^64 is potentially tractable).
Present asymmetric crypto systems can theoretically [1] be attacked with Shor's Algorithm, which may be what you're kind of thinking of if you've heard about "today's encryption getting cracked" in the general media or scifi. And that would in fact be a big deal, it covers how most data is moved around in communications and the Internet at present. But QC isn't magic, and it doesn't just break anything. FDE and the like that just use symmetric crypto are safe.
1: "Theoretically" because that's if (big if) an ideal quantum computer that could be scaled to a sufficient number of qubits is created.
But we can’t know for sure that AES or any other encryption algorithm doesn’t have some as-of-yet-unknown fatal flaw that would make it breakable in some way not necessarily even having anything to do with quantum computers?
After reading this multiple times, and looking up QC (Quantum Computing) and FDE (Full Disk Encryption), I got the following out of it:
- symmetric encryption is safe for AES-256 and up - asymmetric encryption isn't getting cracked because QC isn't magic
Is this a correct TL;DR ?
On the other hand, symmetric encryption can be seen as a super convoluted and costly shift cipher. And it seems that Quantum Computing does not help much with dumb and costly mathematics like this.
As we cannot foresee the future, neither politics nor any future decyphering capacities, I highly doubt deleting the key is a viable option.
Note: Edited for clarity.
The point is to make the data unusable. Obviously when you delete a file from your recycle bin, the data is all still there, but it's acceptable under EU data protection reqs.
No it isn't. This is what got Facebook in hot waters awhile back. Marking a picture as deleted isn't the same as deleting it. Some other mechanism could easily point to where the data is actually located and not just its descriptor.
Deleting the image ID and leaving the content on a CDN is not acceptable - but that's not what I said.
Data for a join, ie foreign keys, are used to inform your structure. They aren’t really data a person owns... they just describe how that data (theirs) fits into your database (yours).
For example, a customer's address is private information; statistics about how many customers come from each town/region is not, but calculating a simple "select town, count(*) from x group by town" requires decrypting every address.
So to recap correct me if I’m wrong:
You store everything encrypted.
You have an api on it which hides the encryption and shows everything unencrypted.
On the unencrypted api you do joins/aggregations.
RightToBeForgotten then means delete its decryption key and remove it from the in-memory api.
Make sure to get any DB backups as well, otherwise the key could still be out there somewhere. If you store the key under version control as well (bad practice but we've all seen it done) you'll need to rewrite git history to make sure the key isn't recoverable at all.
There could be an infinite number of ways a key could unintentionally persist, so something to keep in mind with this approach. Good reason to be disciplined with keys and other secrets to make sure they aren't leaving the environment.