Re: re: deleting data from backups
Eee, when I were a lad, many aeons ago (before GDPR), we did some backups to WORM drives. Not easy to delete some records from them.
As other posters point out, you can devise encryption schemes that allow you to 'forget' how to decrypt data keyed to an individual: assuming each individual has one or many unique IDs which have a list of encryption keys for the actual records linked to them, you 'simply' delete the list of keys, making all records inaccessible. The key management problems are not trivial.
To be honest, I quite like immutable records. I don't want, for example, details of my pension contributions to vanish into the ether; or indeed records of entry to the UK on HMT Empire Windrush. What I don't want is people using them for nefarious purposes: the right to delete is solving the wrong problem, when what you want is to be able to trust people not to abuse personal information. Gaol terms for people/directors of companies abusing that trust, rather than fines that can be written off as 'the cost of doing business' might get people taking things more seriously.