P2P Fortress is a serverless peer-to-peer encrypted file transfer application built with Python and CustomTkinter. It combines military-grade cryptography with an easy-to-use desktop interface.
Cryptographic Stack — Dual encryption using both ChaCha20-Poly1305 and AES-256-GCM per transfer. X25519 ephemeral key exchange for Perfect Forward Secrecy — every session uses a fresh key that is destroyed after use. Argon2id key derivation following OWASP 2023 maximum security parameters: 128 MB RAM and 4 iterations. Short Authentication String (SAS) fingerprinting in 4-word format for detecting man-in-the-middle attacks.
Security & Privacy — Certificate pinning to prevent MITM attacks. Tor network support for anonymous transfers. Burn After Reading mode — files are automatically and securely deleted on the receiver's end after opening.
Transfer Modes — Direct peer-to-peer connections over the local network. Magic-wormhole relay-assisted transfers for connections across different networks. LAN peer discovery using UDP beacons for automatic detection of nearby devices.
File Handling — Multi-file transfers via automatic ZIP compression before encryption. Automatic extraction after decryption on the receiving end. Transfer history logging with SQLite database. Speed monitoring and ETA calculations in real time.
Compression — zstd and zlib compression for faster transfers and smaller file sizes before encryption.
Watch Folders — Set a folder to be monitored. Any new files added to the watch folder are automatically queued for encrypted transfer.
User Interface — CustomTkinter-based GUI with dark and light theme toggle. Offline encryption/decryption mode for securing local files without network transfer.
Technical Stack — Python, CustomTkinter, cryptography library, argon2-cffi. Optional: magic-wormhole, pystray, pillow, plyer, qrcode, zeroconf. Packaged as standalone .exe with PyInstaller. Windows 10/11.
P2P Fortress is open source. Source code and releases are on GitHub.