Can I code 1Password?

COPYDon't build a password manager for daily use — the stakes here are the whole reason, not the difficulty. If you want to understand the mechanics as a learning project, build a toy, single-device vault you never actually rely on: 1. Use an established, audited encryption library (libsodium, via its NaCl secretbox API) — never write your own AES or key-derivation code, that's precisely where subtle, catastrophic mistakes happen. 2. Derive an encryption key from a master password using an established key-derivation function (Argon2id) with real, tested parameters, not ones you picked yourself. 3. Store the encrypted vault as a single local file — no sync, no server, no second device. A simple CLI or local UI to add, view, and search entries. Treat the result as a toy, clearly labeled as such, and never put a real account's password in it. Out of scope, permanently: any form of multi-device sync (zero-knowledge encryption that survives a server compromise is exactly the kind of thing that looks simple and isn't), and anything resembling production hardening — security auditing and a decade of resistance to real attackers isn't a weekend's work, or a year's.