JupyterHub is a production-grade multi-user server for Jupyter notebooks. It provides authentication, spawning of single-user notebook servers, and proxying. Built on Tornado, it uses SQLAlchemy for persistence, supports pluggable Authenticators and Spawners, and includes an OAuth2 provider, RBAC scopes, a REST API, and a web UI. The system is designed for deployment in education, research, and enterprise settings, managing user sessions, isolating notebook environments, and routing traffic through a configurable HTTP proxy. The architecture follows a hub-and-spoke model: the Hub (Tornado process) handles authentication, authorization, and state; the ConfigurableHTTPProxy routes requests to per-user single-user servers; and Spawners manage server lifecycle. Key entry points include the `jupyterhub` CLI command, the `jupyterhub_config.py` configuration file, and the REST API at `/hub/api`. External dependencies include Tornado, SQLAlchemy, Alembic, oauthlib, prometheus_client, and aiohttp. The codebase is well-structured with clear abstractions for authentication, spawning, proxying, and authorization, making it a strong example of a complex web application framework.
This repository is a browser extension for generating two-factor authentication (2FA) TOTP and HOTP codes. It allows users to securely store account secrets (optionally encrypted with a passphrase), generate codes for login, and provides features such as autofill into web pages, cloud backups (Dropbox, Google Drive, OneDrive), and synchronization across browsers. The extension is built with TypeScript and Vue 2.x, using Webpack for bundling and Vuex for state management. It supports multiple browsers (Chrome, Firefox, Edge) and manifests for Manifest V3. The architecture consists of a background service worker (for handling events and cloud sync), a popup UI (for displaying codes and managing accounts), an options page (for settings), content scripts (for autofill and QR code scanning), and an import page. Data flows involve storing encrypted account secrets in browser storage, generating OTPs from these secrets, and securely backing up and restoring data via cloud services or encrypted files. External dependencies include browser APIs, cloud service APIs (OAuth), and cryptographic libraries (argon2-browser, crypto-js, node-gost-crypto). The codebase demonstrates good engineering practices with clear separation of concerns, reusable abstractions for encryption and storage, and a modular structure for UI components and cloud backup providers. It includes internationalization support, a security advisor for recommendations, and a test suite (unit and end-to-end). While the project faces some technical debt due to its reliance on Vue 2.x and complex backup integrations, it remains actively maintained and functional.
Ente is a multi-product, end-to-end encrypted cloud platform providing photo storage (Ente Photos), two-factor authentication (Ente Auth), secure document vault (Ente Locker), social photo sharing (Ente Space), AI chat assistant (Ente Ensu), ephemeral pastebin (Ente Paste), and media casting (Ente Cast). The system is built as a monorepo with a Go server backend, Rust core libraries for cryptography, machine learning, and media processing, and client applications across web (React/Next.js), mobile (Flutter, native Android/iOS), desktop (Electron), and CLI (Go and Rust). Architecture follows a zero-knowledge design: all encryption (XChaCha20-Poly1305, Argon2, X25519) happens client-side, with keys never exposed to the server. The server handles user accounts, file storage (S3-compatible), billing (Stripe), ML indexing, and sharing. Key entry points include the Go server at `server/cmd/museum`, Rust WASM bindings for web crypto, and Flutter apps with native plugins. Data flows involve client-side encryption before upload, server-side metadata storage in PostgreSQL, and decryption on download. External dependencies include PostgreSQL, S3-compatible object storage, Stripe, ONNX Runtime for ML, and various cloud infrastructure (Cloudflare Workers, Grafana, Prometheus).
This repository contains Stratum, a free and open-source two-factor authentication (2FA) app for Android with Wear OS support. It implements TOTP, HOTP, Steam, Yandex, and mOTP code generation algorithms with configurable parameters. The app features encrypted local backups with AES-GCM/CBC and Argon2id/PBKDF2 key derivation, import from over 15 third-party authenticator apps (Aegis, Bitwarden, KeePass, etc.), QR code scanning via CameraX, and a Material Design 3 UI. The architecture follows a clean layered pattern with a core library (Stratum.Core) containing domain entities, OTP generators, backup converters, and service interfaces, a Droid project for the phone UI, and a Wear OS project. The codebase is well-organized with dependency injection (Autofac), repository pattern for SQLite persistence, and unit tests. It demonstrates strong data engineering skills in reverse-engineering and parsing various backup formats, implementing custom cryptography for Ente Auth, and maintaining a large icon database. The project is actively maintained, targets .NET 10, and has localization in 27+ languages.