Learn how to hide text and file inside various file formats
Steganography, used in a digital sense, simply refers to the act of hiding information from a 3rd party observer.
It can also be used entirely as an individual where you wanted to conceal your private sensitive data.
That act of hiding information can translate to either a text, a lengthy message or even embedding a file within another file.
There are only a handful of tools out there that provides actual steganography functions.
After removing those obsolete tools that are either not up-to-date (supports older versions of Windows XP, etc.) or discontinued support, here are the ones that are still working and fits the different file formats you want to hide your data.
Hiding Text on Image Files
This works best when you are using an innocent-looking image file.
Try to go for a JPG file extension image that either you took yourself or downloaded from the Internet.
Use a reliable freeware Hex Editor, open it with the image file and look for clusters of zero bytes where you can freely enter your own text inside without altering the appearance of the image file itself.
Using a Hex Editor to hide data on an image file is the most effective yet simple-to-use method.
Hiding File on Image Files
If you are looking to hide a file within an image file, you can use StegHide.
StegHide allows you to embed a file, example a text file, inside an image file.
It supports both Windows and Linux operating systems and has support for JPEG, BMP, WAV and AU files.
Hiding on PDF, Bitmap and HTML Files
If you are looking to conceal sensitive data inside PDF files, then WbStego4open is the right open source tool.
It supports both Windows and Linux operating systems and is able to work on Bitmap and HTML files as well.
Hiding on MP3, WAV, WMA and Flac Audio Files
Deepsound is stenganography software that hides secret files into audio files.
Yes, you can add files such as doc, jpg or even pdf formats and embed it inside the audio file.
Though the main use of this tool may be injecting copyright marking information, you can use its function to add your sensitive files without altering the state of the audio file itself.
If you are a simple command-line interface tool for MP3 formats, you can give MP3Stego a try.
Hiding on MP4 and MPG Video Files
Not many steganography tools are out there that supports hiding data on video formats.
OpenPuff is one of those and it uses a open source crypto-library called libObfuscate.
It supports video formats such as 3GP, MP4, MPG and VOB.
In addition, it also supports images (BMP, JPG, PNG) and audio formats (MP3, wav) as well.