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Do you now have to write log parsers to extract personal data for everything that previously you just stored for general debugging and security purposes? ... Any engineers now must fully understand the consequences of anything they log and design delete mechanisms for it.

YES YES YES YES YES.

Are you not already doing this for passwords, credit card numbers, and social security numbers?

Such a request is essentially NP-complete.

I think you mean undecidable, or equivalent to the halting problem, or subject to Rice's theorem. NP-completeness is irrelevant. I think you'll find that HN is the last place you'll win arguments by inaccurately using technical terms in the hopes that it will go over other people's heads, Legally Blonde-style (https://www.youtube.com/watch?v=8rNVaY7Stt4).

To anyone who knows what they're talking about, this an obviously nonsensical argument. It's similarly undecidable to verify whether the data that you expose publicly contains customer data, or customer passwords, or your own passwords, but you do it anyway, by restricting your engineers to only write and deploy code that they understand.

> How do you even know all the permutations of personal data that came be stored in the logs. There are possibly infinite possible ways personal information can manifest in logs.

Nonsense. You write the log statements. You know what data structures you are logging.

If you're using some server's built in logging, or some logging library or middleware you don't understand, turn that off until you understand what it's logging.

GP is referring to pseudonymization, not data structures.

Logs that do not contain explicit PII are still rife with pseudo-identifiers that could possibly (but not typically) be used to join activity with PII.

For example:

- You have one set of logs that stores anonymized click activity

- You have another set of logs that stores purchase transactions

- Both have millisecond timestamps

You could potentially link the click record from one logs database to the purchase record in the transaction database, when during a single millisecond there is only one transaction and one click happening. Now your anonymized click ID and all your click activity is linked to your PII in your transaction.

Sometimes it's off by a few millisecond. Sometimes the logs are obfuscated up to the second level, but then you'll still have instances of a single click and transaction in a second. Does this activity still need to be removed from logs, despite not being linked to your PII or even being identifiable? These are the challenges that need to be addressed.

Yes.

Emplify, for example, makes it a point not to reveal averaged responses for subgroups of size less than 5, for similar reasons: https://intercom.help/emplify-insights/en/articles/1731829-c...

We should be making an effort to take such care with all customer data, even just when storing it. Mistakes are inevitable, of course, so small gaps that are soon fixed should be let off with a warning, with any fines proportionate to the amount of exposure and negligence involved. How would we do that? Maybe have an agency of experts tasked with determining the fines, and allowing companies to appeal those fines in open court. Like what GDPR does.

I'm a software engineer who works for a SaaS data analytics startup that has to comply with GDPR. It's not cheap, just like it's not cheap complying with all the laws restricting pollutants emitted by my car, but it's still completely worthwhile.

(My employer is not Emplify, although we are a customer of theirs. Good service.)

That is not how logs work. Did you reply to the right comment?

Exemplify is gating database records from surfacing through their UI. These records still exist in the database and are admin accessible. The act of knowing if clustering the data is too much still requires knowing the data - i.e. the data existing.

Yes, I replied to the right comment, you're getting hung up on an irrelevant detail.

I'm saying that the thought they put into anonymizing the data they surfaced through their UI, that same amount of thought should be put into the data we all store.

If the data can't be clustered in a way that preserves anonymity, it should be deleted (after the desired aggregate statistics are computed). Emplify probably isn't required to, and so they probably don't. I'm saying they should be required to.

It is not known at the time of storing the data if the data being stored will be denonymizable - especially for logs data.

Saying, "Just don't store logs data" is a fundamental misunderstanding of how web development works. This data is crucial for operational uptime, debugging, and running an online business. The scope of the data is so large that there inevitably are factors that can be used for denonymization, which is to GP's point.

The reason I asked if you replied to the right comment is because logs data is fundamentally different from database records, which is the working example you gave you gave with exemplify.

I'm not fundamentally misunderstanding anything. We both understand the problem quite well, you're just refusing to take on the burden of trying to solve the problem.

I didn't suggest not storing any logging data, actually. I suggested deleting it. Old, stale logs are unnecessary for operation uptime or debugging and low-value for usability or security investigation.

They also cumulatively presents risks to customers. A gay blogger in Russia who used LiveJournal in 2004 might regret their decision now, even though in 2007 when LiveJournal sold to a Russian company, few reasonable people would have foreseen the country's turn towards homophobia later. If LiveJournal had, for example, replaced all IP addresses with cities in historical, pre-2007 HTTP logs, they would have lost nothing of value to them while their customers would be that much safer. If they had gone so far as aggregated statistics of requests and unique visitors per tuple of (user agent, city, timestamp truncated to 15-minute intervals), and then deleted detailed all HTTP logs older than 90 days as suggested by Maciej Ceglowski [1], can you think of anything of value they would have lost?

But of course I'm sure they didn't, because they weren't required to put that much thought into the data they stored.

I'm saying we should be required to.

[1]: https://idlewords.com/talks/haunted_by_data.htm

> engineers now must fully understand the consequences of anything they log

I don't think this is quite the dichotomy you make it out to be.

So we can create optimizing compilers, but we can't figure out what to log?

This seems like a problem of never having motivation to solve the problem before.

"We can't do that, it's too hard" is often a mea culpa I'm industry when they oppose regulation. Then they will come up with a solution from having actually spent some effort to actually think of potential solutions.

Oh we can figure out what to log - and figure out how it would suck donkey balls. Just like the other "too hard" areas like the magic golden key backdoor.

It can trivially backfire to make things less secure if it is poorly defined which is generally a given. The GDPR made exfiltration easy as an account compromise - one could argue it is an acceptable trade off for transparency but the regulators must bear full responsibility for their constraints.

"We can't log sensitive customer data slowing down debugging and worsening data integrity" is one thing but now imagine "can't log customer IDs in a read only way as sensitive information" oops there goes a lot of useful auditing information as it is excluded or forced to be writeable.

It's to hard to do anything so lets do nothing.

Yes, if you log personal information like IP addresses you need to have a plan to delete it. Maybe storing it long term is a liability not a benefit.

Don't bring complexity theory into it.

There are a (very) few hard edge cases. But most of this stuff is easily addressed by 1) having good designs around data handling in your system and 2) treating customer data and PII as data you only have limited rights to in the first place.

In Europe, we have GDPR which is broadly similar. And the answer to your question about logs is basically "Tough shit. Personal data is important and if you've been leaving it in logs all over the place then you're going to have to sort that shit out".

The Backups question is a bit more complex. One source I've seen: "According to France’s GDPR supervisory authority, CNIL, organisations don’t have to delete backups when complying with the right to erasure. Nonetheless, they must clearly explain to the data subject that backups will be kept for a specified length of time (outlined in your retention policy)."

Paired with that is that if you're keeping data (or backups) for any length of time beyond the immediate needs of the customer then you need to be able to justify it.

ALL of those scenarios are only problematic because the design of these megalithic services didn't even consider things like the basic privacy of their livestock/user base.

Think this law is going to allow me to require 7-11 to delete me from their DVR records? Not part of the business model, it's a matter of security. Nice straw man though.

Their terrible system design can't handle "FROM PornPrefs DELETE SSN,Name,Address WHERE SSN LIKE "999-11-2222"". They brought this on themselves.