Text Watermarking and Watermark Recovery - Snowdrop

The traditional watermarking relies on embedding some information in a binary file (such a proprietary format document - Adobe PDF, MS Word or multimedia files) to identify the origin of a particular copy. Watermarking can be combined with steganography to hide this data from a casual viewer.

Snowdrop is intended to bring (relatively) invisible and modification-proof watermarking to a new realm of "source material" - written word and computer source codes. The information is not being embedded in the least significant portions of some binary output, as it would be with a traditional low-level steganography, but into the source itself.

Snowdrop provides reliable, difficult to remove stenographic watermarking of text documents (internal memos, draft research papers, advisories and other writing) and C sources (limited distribution software, licensed software, or freely available code) so that:

  * leaks can be identified if the data goes public.
  * Original source can be determined and demonstrated if part of the document is claimed by somebody else, copied without permission, etc ...

Snowdrop Installation:
Open terminal from Applications > Accessories > Terminal, and type following command to install

sudo apt-get install snowdrop

Using Snowdrop:
Snowdrop is a command line tool, the simple way to apply watermark to your source code is by using command ...

sd-c -i input.c output.c "secured"

Now, to extract or compare the watermark, use the following command ..

sd-c -e input.c output.c