Web Crypto API, AES-GCM, React, GitHub API, Primer Design... a deep dive into how GitBox works

[alexcmgit]

GitBox is a E2EE (end-to-end encrypted) file sharing service, it allows people share private files (< 50mb) through their public repositories.

The tech stack is based on:

• React and vite, redux, saga, etc.
• libsodium for cryptography.
• GitHub API as server.
• Primer Design System.

---

GitBox is actually pretty simple, it just manages your files locally using the Web File Reader API, when uploading to GitHub it first encrypts using secret-key encryption (symmetric), then it generates a download URL that is just a URL that points a React route that downloads the raw encrypted file from GitHub servers and decrypt using the decryption key and nonce also provided by the download URL.