🔐 CryptDir Pro v2.10.5

A high-security, streaming file and folder encryption tool built with Python and Tkinter. Designed by COLDMAN for professional-grade security with a user-friendly interface.

This tool is designed to handle directories of any size—from a few files to terabytes—by streaming data in 64KB chunks, ensuring low memory usage even when processing massive files.

(A screenshot of the main application window)

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⚡ Key Features

• AES-256-CTR + HMAC-SHA256: Uses industry-standard, production-grade authenticated encryption (Encrypt-then-MAC) to protect against both eavesdropping and data-tampering.
• Secure Key Derivation: Employs PBKDF2 with 100,000 iterations to stretch your password, making brute-force attacks extremely difficult.
• Streaming Encryption: Processes files in small chunks, allowing it to encrypt/decrypt massive files (50GB+) with minimal RAM usage.
• "Test Decrypt" Utility: Safely verifies file integrity and password correctness by checking the HMAC signature without decrypting, modifying, or writing any data.
• Robust Error Handling:
  • Atomic Operations: Uses temporary files (.encrypting, .decrypting) and atomic os.replace calls to ensure your original files are safe, even if the operation is cancelled or fails.
  • Automatic Backups: Creates a .backup_temp of the original file before processing and automatically restores it if any error occurs.
• Flexible Processing Modes:
  • Folder Mode: Recursively processes every file in a directory (uses a fast, single-pass scan).
  • Files Mode: Allows you to hand-pick specific files for processing.
• Password Strength Meter: Provides real-time feedback on your password's strength.
• Windows Folder Utility: Includes a button to quickly toggle the "Hidden" and "System" attributes for the target folder.

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🚀 How to Use

This application is Windows-only.

Option 1: Download the .exe (Recommended)

This is the easiest method for most users. No Python or setup required.

1. Go to the Releases Page of this repository.
2. Download the latest CryptDir_Pro.exe file.
3. Place the .exe in any folder and double-click to run it.

Option 2: Run from Python Source

This is for developers or users who prefer to run directly from the source code.

Requirements:

• Windows 10 / 11
• Python 3.7+
• Required library: cryptography

Running:

1. Install the required library:

   pip install cryptography

2. Download the CryptDir_ProV2.10.5_secure_streaming.py file.
3. Run the script from your terminal:

   python CryptDir_ProV2.10.5_secure_streaming.py

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🛡️ Security Model

Security is the primary focus of this tool. It does not roll its own crypto and relies on the standard cryptography library.

• Cipher: AES-256 in Counter (CTR) mode. CTR is a streaming mode, making it ideal for files of any size.
• Authentication: HMAC with SHA-256. This is applied after encryption (Encrypt-then-MAC) to create an authenticated ciphertext. Any modification to the encrypted file will cause the HMAC verification to fail, preventing decryption of corrupt or tampered data.
• Key Derivation (KDF): PBKDF2-HMAC-SHA256.
  • Iterations: 100,000
  • Salt: A 16-byte random salt is automatically generated (salt.key) or can be provided manually.
  • Output Key: 64 bytes (32 bytes for the AES encryption key, 32 bytes for the HMAC authentication key).

Versioned File Format

The tool uses a custom, versioned file format (v2.10) to ensure future compatibility.

Offset	Length	Description
0	5 bytes	Magic Bytes (b'CDPRO')
5	2 bytes	Version (b'\x02\x0A')
7	1 byte	Reserved (b'\x00')
8	16 bytes	Initialization Vector (IV)
24	8 bytes	Original File Size (Struct <Q)
32	N bytes	Encrypted Data
32+N	32 bytes	HMAC-SHA256 Tag

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⚠️ !! CRITICAL WARNING !! ⚠️

This is a powerful encryption tool. Failure to follow instructions WILL result in permanent data loss.

1. NO RECOVERY: If you lose your Password OR your salt.key file (if one was generated), your data is PERMANENTLY AND IRRECOVERABLY LOST. There is no backdoor.
2. BACKUP FIRST: Always back up your important files to a separate location before performing any encryption or decryption.
3. DO NOT INTERRUPT: While the tool has safeguards, forcefully killing the process (e.g., via Task Manager) or a sudden power loss during an operation may corrupt the file being processed. Always use the "CANCEL OPERATION" button.

The author (COLDMAN) is not responsible for any data loss or damage resulting from the use of this software. Use at your own risk.

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License

This project is licensed under the MIT License.