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Overview
Assa2i9 lets learners practice theory questions with images and audio, take randomized quizzes, retake past ones from their history and review corrections, all without an internet connection.
Because the question bank has real value, the app protects it: the database and media are encrypted, the key lives in the operating system keychain and is tied to the machine it was first run on, and the interface blocks screenshots and copying.
What I built
- Built a cross-platform desktop quiz app on Tauri 2, React and Rust with random quizzes, history and review.
- Encrypted data at rest with SQLCipher and AES-256-GCM media, with keys held in the OS keychain.
- Bound the key to a hardware fingerprint with a lock screen, plus screenshot and copy protection.
- Shipped a Windows installer through Docker cross-compile CI, with CLI importers and a Slint native UI.
Design and architecture
- A shared Rust core crate owns the encrypted database, crypto, importers and repository layer, and is reused by the Tauri app, a command-line tool and a Slint prototype.
- Device lock: a fingerprint built from stable machine identifiers that survive OS updates, so the app locks only when moved to different hardware.
- Question content is built with Python and Node tooling for extraction, OCR and JSON import, then shipped encrypted.
- Release: a Dockerized cross-compile produces the Windows NSIS installer and a portable build from a GitHub Actions workflow.