Steganography is to hide data in images (or different types of files), can be hidden, for example:
The rightmost bist that makes up an image, is called the least significative byte (LSB), they can be modified without a change in the appearance of the image.
This technique modifies the image, it is mostly used with grayscale images, or noisy pictures like the sea, and the information will be store in those parts, actually modifying the image.
This technique, hides the information in mathematical functions like compression algorithms.
To hide something in a picture using steghide we need to run the following command:
steghide embed -ef [file_to_embed] -cf [container_file]
And to extract it we can run:
steghide extract -sf [stego_file]
Snow adds tabs and spaces to a text file, to hide a message. It works like this:
stegsnow -C -m [message] -p [password] [input_file] [output_file]
And to extract the information we run the following command:
stegsnow -C -p [password] [file_with_information]