5 ms·

This is an excellent solution. I don’t see why it couldn’t be the industry standard.

Silhouette 5y ago
It's a solution that looks clever at first sight but the devil is in the details. Sometimes it's difficult to determine what data is subject to erasure in the first place, for example if there are multiple parties involved or the obligation to erase conflicts with other obligations that might require retention of some of the personal data. If you're going with the encryption and key management strategy, your design must accommodate all possible scenarios both now and in the future including those where the rules change between now and then. For anything but the simplest cases that seems unlikely.
- bottled_poe 5y ago
  Seems easy to me. 30 days, delete backup keys. What’s the problem? You still have 29 day old backups?
  - Silhouette 5y ago
    Maybe we're talking about slightly different things here. The suggestion to use individual keys to encrypt personal data is usually made so that deleting a key has effectively and immediately destroyed all copies of the data including any historical ones. That way you're definitely fully compliant with any right to be forgotten requests with one simple act. Even if you do have some older backups or archives kept around or the backup data isn't truly irretrievable from the physical media where it was stored after being marked for deletion, that data instantly becomes random noise without the key (which you obviously don't store and backup in the same way in this kind of scheme). In other words, it's not really about whether keeping backups for a few days or a few weeks before they are "deleted" would be considered acceptable by regulators, it's about making all such questions irrelevant while otherwise being able to continue with business as usual. It would be a clever and useful solution to the regulatory compliance problem in this area, if it worked in practice.
jandrewrogers 5y ago
It doesn't work in real systems because it is extremely costly to the point of being infeasible. This has been known for decades and rejected because it doesn't actually work. If a technical solution is "obvious" and no one is using it, it tends to imply that it has serious flaws that are obvious to domain experts. Using encryption for deletion is known to be deeply flawed for unavoidable technical reasons. These databases actually exist. Almost no one uses them because the performance is exceptionally poor to the point of being nearly unusable for practical things.
- bottled_poe 5y ago
  I disagree. Why doesn’t time-bounded deletion of backup keys work?

It's a solution that looks clever at first sight but the devil is in the details. Sometimes it's difficult to determine what data is subject to erasure in the first place, for example if there are multiple parties involved or the obligation to erase conflicts with other obligations that might require retention of some of the personal data. If you're going with the encryption and key management strategy, your design must accommodate all possible scenarios both now and in the future including those where the rules change between now and then. For anything but the simplest cases that seems unlikely.

bottled_poe 5y ago
Seems easy to me. 30 days, delete backup keys. What’s the problem? You still have 29 day old backups?
- Silhouette 5y ago
  Maybe we're talking about slightly different things here. The suggestion to use individual keys to encrypt personal data is usually made so that deleting a key has effectively and immediately destroyed all copies of the data including any historical ones. That way you're definitely fully compliant with any right to be forgotten requests with one simple act. Even if you do have some older backups or archives kept around or the backup data isn't truly irretrievable from the physical media where it was stored after being marked for deletion, that data instantly becomes random noise without the key (which you obviously don't store and backup in the same way in this kind of scheme). In other words, it's not really about whether keeping backups for a few days or a few weeks before they are "deleted" would be considered acceptable by regulators, it's about making all such questions irrelevant while otherwise being able to continue with business as usual. It would be a clever and useful solution to the regulatory compliance problem in this area, if it worked in practice.

jandrewrogers 5y ago

It doesn't work in real systems because it is extremely costly to the point of being infeasible. This has been known for decades and rejected because it doesn't actually work. If a technical solution is "obvious" and no one is using it, it tends to imply that it has serious flaws that are obvious to domain experts. Using encryption for deletion is known to be deeply flawed for unavoidable technical reasons. These databases actually exist. Almost no one uses them because the performance is exceptionally poor to the point of being nearly unusable for practical things.

bottled_poe 5y ago
I disagree. Why doesn’t time-bounded deletion of backup keys work?