PassLock — Cross-Platform File & Folder Password Protection

Encrypt and decrypt files and folders on Windows, macOS, and Linux using AES-256 encryption — with both a GUI and a CLI.

Features

• AES-256-CBC encryption with PBKDF2-HMAC-SHA256 key derivation (600,000 iterations)
• HMAC-SHA256 integrity verification (detects tampering and wrong passwords)
• Encrypt individual files or entire folders
• Graphical UI (tkinter) — no command line needed
• CLI for scripting and terminal workflows
• Cross-platform — works on Windows, macOS, and Linux (Python 3.9+)
• Installable as a Python package or standalone executable

---

Quick Start

Option A — Install as a Python package

# From the project directory:
pip install .

# Launch the GUI:
passlock-gui          # or: python -m passlock

# Use the CLI:
passlock lock secret.pdf
passlock unlock secret.pdf.locked

Option B — Run without installing

pip install -r requirements.txt

# GUI
python -m passlock

# CLI
python -m passlock lock /path/to/file
python -m passlock unlock /path/to/file.locked

Option C — Standalone executable (no Python needed)

See Building Standalone Executables below.

---

GUI

Launch the graphical interface:

passlock-gui          # if installed via pip
python -m passlock    # without installing
passlock gui          # CLI sub-command

The GUI lets you:

• Browse for files or folders
• Enter your password in a dialog (with confirmation for locking)
• Toggle "keep original" option
• See a real-time log of operations

---

CLI Usage

Lock (encrypt) a file

passlock lock /path/to/secret.pdf

You'll be prompted to enter and confirm a password. The original file is replaced with secret.pdf.locked.

Lock (encrypt) a folder

passlock lock /path/to/my_folder

The folder is archived, encrypted, and saved as my_folder.locked. The original folder is removed.

Unlock (decrypt)

passlock unlock /path/to/secret.pdf.locked
passlock unlock /path/to/my_folder.locked

Keep originals

Use --keep to retain the original file/folder after locking or the .locked file after unlocking:

passlock lock   myfile.txt --keep
passlock unlock myfile.txt.locked --keep

---

Building Standalone Executables

Build a single-file executable for your OS using PyInstaller:

macOS / Linux

chmod +x build.sh
./build.sh

macOS output: dist/PassLock.app (drag to Applications) Linux output: dist/passlock (copy to /usr/local/bin/)

Windows

build.bat

Output: dist\PassLock.exe

To create a proper Windows installer, compile installer_win.iss with Inno Setup.

---

OS Compatibility

OS	Python	GUI	CLI	Standalone
Windows 10/11	3.9 – 3.13	✅	✅	.exe (PyInstaller)
macOS 12+	3.9 – 3.13	✅	✅	.app bundle (PyInstaller)
Ubuntu 20.04+	3.9 – 3.13	✅	✅	binary (PyInstaller)
Debian / Fedora / Arch	3.9+	✅	✅	binary (PyInstaller)

Note (Linux): tkinter may need to be installed separately: sudo apt install python3-tk (Debian/Ubuntu) or sudo dnf install python3-tkinter (Fedora).

---

Security Details

Property	Value
Cipher	AES-256-CBC
Key derivation	PBKDF2-HMAC-SHA256, 600 000 iterations
Salt	32 bytes, cryptographically random
IV	16 bytes, cryptographically random
Integrity	HMAC-SHA256 (encrypt-then-MAC)
Padding	PKCS7

Encrypted File Format

PLCK (4 B) | version (1 B) | salt (32 B) | IV (16 B) | ciphertext (var) | HMAC (32 B)

Project Structure

passlock/
├── __init__.py      # package metadata & version
├── __main__.py      # python -m passlock entry point
├── core.py          # encryption engine
├── cli.py           # command-line interface
└── gui.py           # graphical interface (tkinter)
pyproject.toml       # package config (pip install .)
passlock.spec        # PyInstaller build spec
build.sh             # macOS / Linux build script
build.bat            # Windows build script
installer_win.iss    # Inno Setup script (Windows installer)
requirements.txt     # pip dependencies

Requirements

• Python 3.9+
• cryptography package
• tkinter (included with Python on Windows/macOS; install separately on some Linux distros)