Steghide is a free and open source steganographic software for Linux and Windows. Using Steghide, you can hide very sensitive and confidential data files in your image or audio files. It supports JPEG, BMP, WAV and AU files. It comes with embedded data compression and encryption, embedding of a checksum to verify the integrity of the extraced data, graph-theoretic approach, CRC32 algorithm and more. It is released under GNU General Public License.
How to Install Steghide on Ubuntu
Steghide is available in the default Ubuntu repositories. Open the terminal command-line application (ctrl+alt+t) and run below Steghide apt installation command.
sudo apt install steghide
Hide File Inside an Image using Steghide
Put the confidential secret file and the the image or audio file in the same folder.
In my case its Home directory, secret file.txt and rose.jpg image.
In the terminal run below
steghide embed -ef file.txt -cf rose.jpg
You will be asked to enter a password. Enter password and confirm again.
Extract Secret File from the Image
Now delete the secret file from the Home directory (file.txt) and in the terminal application run below command. It will extract the file.txt from the rose.jpg image file
steghide extract -sf rose.jpg
Now enter your encrypted password to extract it. Now check file.txt in your Home directory.
For the complete usage details run below command.