Let's say I want to create private archives for the long term (e.g. more than 30 ). The archives' sizes could be anywhere from 1 GB to 30 GB. As far as I understand I could go down two ways:
The first would be for example using plain AES-256 encryption in CTR mode with a random key stored on paper.
The second, more suitable solution for backups, is using the Offline Private Key Protocol, e.g. generate a 4096 bit RSA key pair and encrypt with random AES-256 keys that get stored with the archives (key-wrapping) while the private part is again stored on paper. Kind of like Safeberg does.
My question is which of the two methods would be least susceptible to currently envisioned attacks in the next 30 years, coming from adversaries with resources such as your average government (i.e. not the NSA). What about quantum computing? Additionally I would like to know if there are any other, better alternatives or any improvements that I could make to both ideas without changing their practicality.