Comment by cyphar

There are much better systems for splitting data than just chunking it into N chunks, the most common is Shamir Secret Sharing[1] (the main benefit being that you can construct an M-of-N scheme easily and having N-1 shards provides you zero information about the secret). One word of caution -- a lot of software developers get enamored by the idea of information-theoretic security when they first run into it, but you eventually realise that useful applications of tools like SSS are actually quite rare.

Shameless plug: I wrote a project a few years ago to create PDF-based backups with sharded keys which would do exactly what I suspect you want[2], unfortunately I got stuck at the "make a nice UI for it" stage (everything works but it's just a CLI tool at the moment). I guess I should take a look at using an LLM for that these days... (I used this to store my password manager root password and necessary keys to pull and decrypt the encrypted backups of my server.)

[1]: https://en.wikipedia.org/wiki/Shamir%27s_secret_sharing [2]: https://github.com/cyphar/paperback/