# Stegano

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[Stegano](https://sr.ht/~cedric/stegano), a pure Python Steganography
module.

Steganography is the art and science of writing hidden messages in such a way
that no one, apart from the sender and intended recipient, suspects the
existence of the message, a form of security through obscurity. Consequently,
functions provided by Stegano only hide messages, without encryption.
Steganography is often used with cryptography.

For reporting issues, visit the tracker here:
https://todo.sr.ht/~cedric/stegano


## Installation


```bash
$ poetry install stegano
```

You will be able to use Stegano in your Python programs.

If you only want to install Stegano as a command line tool:

```bash
$ pipx install stegano
```

pipx installs scripts (system wide available) provided by Python packages into
separate virtualenvs to shield them from your system and each other.


## Usage

A [tutorial](https://stegano.readthedocs.io) is available.


## Use Stegano as a library in your Python program

If you want to use Stegano in your Python program you just have to import the
appropriate steganography technique. For example:

```python
>>> from stegano import lsb
>>> secret = lsb.hide("./tests/sample-files/Lenna.png", "Hello World")
>>> secret.save("./Lenna-secret.png")
>>>
>>> clear_message = lsb.reveal("./Lenna-secret.png")
```


## Use Stegano as a command line tool

### Hide and reveal a message

```bash
$ stegano-lsb hide -i ./tests/sample-files/Lenna.png -m "Secret Message" -o Lena1.png
$ stegano-lsb reveal -i Lena1.png
Secret Message
```


### Hide the message with the Sieve of Eratosthenes

```bash
$ stegano-lsb hide -i ./tests/sample-files/Lenna.png -m 'Secret Message' --generator eratosthenes -o Lena2.png
```

The message will be scattered in the picture, following a set described by the
Sieve of Eratosthenes. Other sets are available. You can also use your own
generators.

This will make a steganalysis more complicated.


## Running the tests

```bash
$ python -m unittest discover -v
```

Running the static type checker:

```bash
$ mypy stegano
```


## Contributions

Contributions are welcome. If you want to contribute to Stegano I highly
recommend you to install it in a Python virtual environment with poetry.


## License

This software is licensed under
[GNU General Public License version 3](https://www.gnu.org/licenses/gpl-3.0.html)

Copyright (C) 2010-2022 [Cédric Bonhomme](https://www.cedricbonhomme.org)

For more information, [the list of authors and contributors](CONTRIBUTORS.md) is available.
