tldr:

Data path: file → fixed-size chunks → encrypt each block → erasure-code into n shards → upload shards to n servers

Key derivation: nsec → random per-file key → derived per-block subkey

nostr:naddr1qqgxxdryxfsnxvf3xscnvdnx8pnr2qg5waen5te0xyerwt3s9cczuvf6xsurvwf0qgst0mtgkp3du662ztj3l4fgts0purksu5fgek5n4vgmg9gt2hkn9lqrqsqqqa28ajp369