Mini Diarium is a cross-platform journaling tool prioritizing privacy and security. Built with Tauri, SolidJS, and Rust, it encrypts entries locally using AES-256-GCM without cloud sync or telemetry. The app replaces outdated tools like Samuel Meuli’s Mini Diary, offering modern features while retaining simplicity. 21 stars on GitHub reflect its niche appeal among privacy-focused users.

Key innovations include X25519 key file authentication, allowing users to unlock diaries via SSH-style key files alongside passwords. This enables physical security factors (e.g., USB drives) and integration with password managers. The architecture uses a wrapped master key design: a random AES key encrypts entries, while authentication methods store encrypted key fragments. Unlocking triggers ECDH key exchange and HKDF derivation to recover the master key, ensuring no plaintext storage.

Technical depth extends to layered security: entries auto-save as encrypted SQLite records, backups trigger on unlock, and themes customize the interface. Users can import Day One or jrnl formats with conflict resolution, while export options include JSON and Markdown. Automatic backups rotate based on unlock events, and stats track journaling habits.

For developers, Mini Diarium’s Tauri backend handles UI-Rust communication via Tauri’s `invoke()` API, while SQLite manages local storage. The app avoids HTTP clients and update checks, emphasizing offline reliability. To install, users verify checksums on Linux or bypass macOS Gatekeeper warnings. A critical security note: losing both password and key files means permanent data loss, reinforcing the need for backups.