Security

ENC is built on a “Zero Trust” architecture for code execution.

Architecture Overview

  1. Encrypted at Rest: All project files are stored as encrypted ciphertexts using gocryptfs (AES-256-GCM). The keys to decrypt these files are never stored on the server’s disk.

  2. SSH Tunneling: All client-server communication happens over an encrypted SSH tunnel.

  3. InMemory Decryption: When a project is “mounted”, it is decrypted virtually into RAM. If the server loses power, the decrypted view vanishes instantly.

Why SSH Keys?

We use SSH keys (Ed25519 recommended) for authentication because they are:

  • Cryptographically Strong: Much harder to brute-force than passwords.

  • Non-Phishable: The private key never leaves your local machine.

  • Auditable: The server can track exactly which key accessed which resource.

Session Security

ENC implements a multi-layered session monitoring system to ensure integrity and automatic cleanup.

Session Monitoring Protocols

1. Server-Side Monitoring

  • Inactivity Timeout: Sessions are strictly limited. If no CLI commands are executed or no file activity is detected for 10 minutes (600 seconds), the session is automatically closed.

  • Mount Activity Keep-Alive: The server monitors active mounts. As long as you are reading or writing files in the mounted project, the session stays alive.

  • Closure Conditions: * Command Timeout: > 10 mins idle. * Mount Timeout: > 10 mins without file IO. * Explicit Logout: enc logout.

2. Client-Side Monitoring

  • Project Integrity Monitor: The CLI checks every 3 seconds to ensure your local mount point is valid. If the connection drops or the directory is tampered with, it forces a local unmount to prevent stale handles.

  • Session Watchdog: A background process monitors your terminal window (Parent PID). If you close the terminal or kill the shell, the watchdog immediately triggers a secure logout sequence, ensuring no session is left dangling.

3. Isolation

  • Auto-Lock: If the SSH connection drops, the server automatically unmounts the decrypted project view.

  • Sandboxing: Each user runs in a restricted shell environment, preventing lateral movement within the server OS.