Carpenter

Command-line tool to split files into multiple parts and reconstruct them later. Supports ZIP compression with AES-256 encryption.

Features

• Split any file into N equal parts
• Optional ZIP compression with AES-256 encryption
• Full Unicode password support (including special characters like ñ, Ñ, é, etc)
• Cross-platform: files split on Linux, macOS or Windows can be joined on any of them
• Automatic MD5 integrity verification
• Automatically detects all parts in a sequence (provide any part, not just the first)
• Refuses to join if parts before the one you provided are missing
• Warns about leftover parts from a previous split that would corrupt the join
• Automatically detects if ZIP files require a password
• Low memory usage: plain parts are streamed in 1 MiB chunks (with password protection, one part at a time is held in memory, pick a part count that keeps parts reasonably sized for very large files)
• Fully interactive mode
• Option to delete fragments after reconstruction

Requirements

• Python 3.8+
• pyzipper. Only needed for password protection. Offered for installation on first run if missing.

Manual installation

pip install pyzipper

Installation

https://github.com/function0xMarki/Carpenter.git
cd Carpenter
chmod +x carpenter.py

Usage

Split a file

python3 carpenter.py --split file.jpg

The program will ask interactively:

1. How many parts? (minimum 2)
2. Password protection? (y/n)
   • Yes → asks for password and confirmation, generates .zip files with AES-256
   • No → generates plain .part files

A subdirectory named after the file is created with all parts inside:

photo/
  photo_0.zip   ← metadata (MD5 + original filename), encrypted
  photo_1.zip   ← data part 1, encrypted
  photo_2.zip   ← data part 2, encrypted

Or without password:

photo/
  photo_0.part  ← metadata (MD5 + original filename)
  photo_1.part  ← data part 1
  photo_2.part  ← data part 2

Join parts

python3 carpenter.py --join photo_2.zip

You can provide any part from the sequence, the program finds all parts automatically.

The program will:

1. Locate all parts in the directory (refusing if any part before the one you provided is missing)
2. Ask for the password if the files are encrypted
3. Reconstruct the original file
4. Verify MD5 integrity
5. Offer to delete the fragment files

Help

python3 carpenter.py --help

Tests

python3 test_carpenter.py

Runs 60 black-box checks covering split/join round-trips (plain and encrypted), Unicode passwords and filenames, error paths and edge cases. Optionally pass a path to test another copy of carpenter.py; the --baseline flag skips checks for behavior added in the 2026-07 review so the suite can also run against older versions.

File structure

When splitting photo.jpg into 3 parts:

File	Content
photo_0.part / photo_0.zip	MD5 checksum + original filename
photo_1.part / photo_1.zip	Data (part 1 of 3)
photo_2.part / photo_2.zip	Data (part 2 of 3)
photo_3.part / photo_3.zip	Data (part 3 of 3)

Part _0 contains metadata only. Parts _1 onward contain the actual data.

Arguments

Argument	Description
--split <file>	Split a file (interactive)
--join <part>	Reconstruct from any part in the sequence
-h, --help	Show help

Security

• Passwords are entered interactively and never displayed on screen
• Password confirmation required when splitting
• AES-256 encryption via pyzipper (WinZip AES format)
• Passwords are always encoded as UTF-8 before key derivation, ensuring identical results across Linux, macOS, and Windows
• MD5 checksum verifies file integrity after reconstruction
• The filename stored in part 0 is reduced to its base name when joining, so a crafted archive cannot write outside the fragment directory

Note: Files created with password protection are only compatible with Carpenter or tools that support WinZip AES-256 encryption (such as 7-Zip or WinZip). Files created without a password are standard raw binary parts with no container format.