Can anonymized data be used?

Question

Law in IT

Good afternoon. I had a burning desire to make a website for checking a passport for the presence of data in the public domain.
I would like to know if it is possible to take any leaked (leaked to the network) database (of any enterprise or organization) that contains the full name and passport data of customers, and then copy ONLY the series and number (nothing more!) of EACH client from this database to to your site?
The functionality is approximately the following: a person enters the site, enters the series and number of his passport, and if this series and number appeared in the leak, the site reports that there was a leak of such and such a number from such and such a company...
Is it possible to store these do you have the series data and passport numbers from these databases? Will there be a violation of the law on personal data and so on ...?

Answer 1

In fact, you started violating the law on personal data already when you started working with this database. After all , the law clearly states:
and in other cases, under which yours does not fall in any way.
But if you really want to, then generate hash functions for each number and series and store hash functions, check against them. So you kind of don’t store any personal data, it turns out, but this is also a gray area, something like torrents.

Answer 2

The option suggests itself that yes, your passport has not been lit up anywhere before, but now it is in our database. I would not enter my passport on the left site.

Answer 3

Will there be a violation of the law on personal data and so on ...?

It will be, it will be :) The database, even if it is in the public domain, was still leaked in violation of the law. This time. The series and Passport Number already allow you to uniquely identify a person, therefore they are PD. And according to the law, PD can only be used with the consent of the owner.
Such a site is, let's say, "on the verge of legality" even if only hashes calculated from the series and numbers are stored there.