NLCrypt: Semantic Cryptography

NLCrypt is an attempt to create a cryptography system that doesn't look like a cryptography.

It disguises a secret message as a grammatical (but nonsensical) text by changing its meanings.

Demo

http://nlcrypt.tabesugi.net/

How It Works

http://euske.github.io/nlcrypt/

Installation

Prerequisites:

• Python 2.6 or above (Python 3 is not supported).
• WordNet-3.0. http://wordnet.princeton.edu/

How to build:

Unpack the WordNet tarball as WordNet-3.0 then type this.

$ make

After this you should see w2g.cdb and g2w.cdb files.

Command Line Usage

Syntax:

$ nlcrypt.py [options] key [file ...]

Options:

• -c codec ... Specifies a Python codec (default: utf-8)
• -b basedir ... Directory for dictionary files (w2g.cdb and g2w.cdb)
• -R ... Reverse the direction (decryption).
• -C ... Enables CBC mode. It makes the encrypted text even more nonsensical (but probably harder to guess the meaning).

Acknowledgements

• WordNet is used as a dictionary.
• Sample texts are taken from Bruce Schneier's quotes.