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What is Steganography ?
In Cybersecurity Steganography is a method to embed a secret message or a file in another file, message, image or video. For example a image file hidden in a video file or vice versa. The word steganography is derived from Greek word steganos (στεγανός) meaning “covered or concealed” and -graphia (γραφή) meaning “writing”.
Steganography replaces unrequired bits of files with secret data. Unlike cryptography that protects the data, Steganography hides the data. Nowadays, steganography is most widely used by cybercriminals or by those who creates malwares and cyber-espionage tools.
Types Of Steganography
Steganography is done in so many ways, but in cybersecurity most popular methods are Least Significant Bit (LSB) and Injection.
Least Significant Bit
In any type of file whether it be a image file, video file or any other type of file. There are some bytes in file that are very less important or not needed. These unneeded bytes can be replaced with a secret message without damaging the file. In this way, it makes the secret message to be undetectable with the naked eye.
Another technique is to directly inject the message you want or a file you want to hide in another files but as result this will increase the size of the file.
There are various tools that are available on internet to hide secret message in files. In this blogpost I’ll explain you how to perform steganography using steghide tool.
For Windows and Linux you can download this tool by clicking here and then use this tool using command prompt or terminal. Although there is no need to download this tool externally in Linux. Because, it is already available through package manager. For some reasons , if it is not available then you can download it.
Now, to hide a file in another file using steghide follow the steps mentioned below
- Install steghide using package manager or the link above. I’m using Debian, so I’ll use apt.
sudo apt install steghide
- Use the below command to hide a text file in a image file. For example message.txt in nature.png
steghide embed -cf nature.png -ef message.txt
After you execute the above command it will ask to create a password that will be used for extracting the message
- If you have a image file or any other file that has secret message, you can extract it using below command. For example, extracting secret text from nature.png
steghide extract -sf nature.png
It will ask for the password that was entered while hiding that message.
This is was the basic commands to hide and extract hidden message or file. You can get the list of commands by typing just
steghide in terminal or you can read the documentation of this tool here.
There are so many tools like steghide that hides that file in another file. But steghide supports multiple file types, like hiding a secret message in audio file. I just told you some common commands to hide and extract message. Make sure to read all the other commands available to do so many things by typing steghide in terminal.
You can also watch my video about this I’ve demonstrated everything from installing steghide to hiding and extracting messages.
Read This Too : What Is Ransomware ?