[miki123211]

This is very, very hard in practice.

With how modern systems, languages, databases and file systems are designed, deletion often means "mark this as deleted" or "erase the location of this data". This is true on all possible levels of the stack, from hardware to high-level application frameworks.

Changing this would slow computers down massively. Just to give a few examples, backups would be prohibited, so would be garbage collection and all existing SSD drives. File systems would have to wipe data on unlink(), which would increase drive wear and turn operations which everybody assumed were O(1) for years into O(n), and existing software isn't prepared for that. Same with zeroing out memory pages, OSes would have to be redesigned to do it all at once when a process terminates, and we just don't know what the performance impact of that would be.

[Gigachad]

You just do it the way fast storage wipes do it. Encrypt everything, and to delete you delete the decryption key. If a user wants to clear their personal data, you delete their decryption key and all of their data is burned without having to physically modify it.

[jandrewrogers]

That only works if you have a single key at the block level, like an encryption key per file. It essentially doesn’t work for data that is finely mixed with different keys such as in a database. Encryption works on byte blocks, 16-bytes in the case of AES. Modern data representations interleave data at the bit level for performance and efficiency reasons. How do you encrypt a block with several users data in it? Separating these out into individual blocks is extremely expensive in several dimensions.

There have been several attempts to build e.g. databases that worked this way. The performance and scalability was so poor compared to normal databases that they were essentially unusable.

[girvo]

It would be very hard to change technically, yes.

But that's not the only solve. It's easy to change the words we use instead to make it clear to users that the data isn't irrevocably deleted.