Forensicssteganographywatermarkingtextc-codeforensicssecurity

Snowdrop

Snowdrop provides steganographic watermarking for text documents and C source code to track leaks and prove originality. It uses redundant encoding across multiple channels for resilience against modifications like reformatting or spell checking.

Description

Snowdrop is a tool for embedding reliable, hard-to-remove watermarks into English text documents and C source code. It helps identify leaks if sensitive data like internal memos, research papers, or licensed software becomes public, and proves original authorship if content is copied without permission.

The package includes three commands: sd-eng and sd-engf for watermarking draft-quality and fine-quality English text respectively, and sd-c for experimental C source code watermarking. Watermarks are retrievable from as little as 5-10 lines and survive many alterations due to redundant storage in independent channels.

Useful in forensic investigations and security operations, Snowdrop is currently in beta and may produce corrupted results, especially with C code. Users must retain original un-watermarked files to verify watermarks later.

How It Works

Snowdrop encodes an MD5-based watermark using techniques like whitespace reformatting, typo insertion, word substitutions, punctuation changes, and for C code, logic reordering and variable name mangling. It employs four redundant logical channels for resilience against modifications including reformatting and spell checking. Watermarks are stored in a user database at ~/.snowdrop/database, with 32-bit default or 64-bit via -6 option.

Installation

bash
sudo apt install snowdrop

Flags

-iInject a watermark into a file, requiring original file, output file, recipient info, and optional comment.
-eExtract a watermark from a file, needing the original file and the suspect watermarked file.
-lList the contents of the watermark database for the specific program.
-6Enable 64-bit watermarking instead of the default weak 32-bit watermark.

Examples

Injects a watermark into an English text file with recipient and optional comment.
sd-eng [-6] -i origfile newfile "Recipient" ["Comment"]
Extracts watermark from a potentially watermarked English text file using the original.
sd-eng [-6] -e origfile newfile
Lists contents of the sd-eng watermark database.
sd-eng [-6] -l
Injects a fine-quality watermark into English text with recipient and optional comment.
sd-engf [-6] -i origfile newfile "Recipient" ["Comment"]
Extracts watermark from fine-quality watermarked English text using the original.
sd-engf [-6] -e origfile newfile
Lists contents of the sd-engf watermark database.
sd-engf [-6] -l
Injects an experimental watermark into C source code with recipient and optional comment.
sd-c [-6] -i origfile newfile "Recipient" ["Comment"]
Lists contents of the sd-c watermark database.
sd-c [-6] -l
Updated 2026-04-16kali.org ↗