Over the past couple of years, Steganography has been the source of a lot of discussions, particularly it was suspected that terrorists connected with the Twin Tower attack in New York, USA on September 11th, 2001 might have used it for covert communications. The terrorists might insert the secret message in the photographs with the help of Image Steganography method! Besides, German spies in World Wars had used this hiding technique.
You might have known some physical hiding techniques like hiding messages within Wax Tables, writing messages on paper with secret ink or soap, Morse code written messages on knitting yarn and so on. With the technological developments, the same hiding practice is carrying out in Digital medium too. Yes, messages conceal in sound/image files, altering the sound’s file’s echo, attaching information in uncared file section etc are some of the digital techniques of Steganography.
Steganography & Cryptography
Steganography is related to Cryptography, but it is a different one! Yes, Cryptography is a method to scramble the message so that the others cannot understand. In Steganography, information get hide in other information. Both the techniques can be used to protect your data from the unwanted folks.
Types of Steganography
Check the 4 major kinds of Steganography!
- Text Steganography – It’s a method of hiding data in the text.
- Image Steganography – Here, the secret key is used to embed the message in a digital image and receiver can extract the hidden details using the same key. Others can note the image transmission, but it is impossible to know the existence of the concealed communication.
- Audio Steganography – It’s a way of masking the audible sound within the other louder audible sound.
- Protocol Steganography – If data is embedded inside the network protocols like IP or TCP, it is called Protocol Steganography.
Different Steganography Techniques
Following are the some of the popular techniques of Steganography!
- Spatial domain Technique
In this method of Steganography, secret message gets hide in the form of bits. As the human eyes are barely visible to find the changes in the LSBs (Least Significant Bit) of pixel values, surreptitious data will get hide in them. Here, the image degradation will be less and hiding capacity is more but the hidden data is vulnerable.
- Transform Domain Technique
In Transform domain technique, it is somewhat complex to hide message in the image. Yes, several algorithms are involved in embedding the data in the frequency domain of the signal and thus this Steganography method is much stronger. Nowadays, most of the Steganographic systems use this technique since it is better than the LSB process that I’ve discussed just above.
- Masking & Filtering
This is the most robust method than spatial domain method and it uses the Watermarking techniques. Here, the image is marked which is primary to the cover image to hide the information. Then the masked image needs to be filtered to get the covert data.
- Distortion Technique
In this method, a set of changes will be applied to the cover image to create a Stego-object. While transmitting the image, those alterations will be used to match the concealed data and gets encoded. So, the stego-image will reach the receiver instead of cover image and it will be decoded to see the hidden message.
There are 1000’s of Steganography tools available on the Internet. I recently found a good software “Our Secret” to perform Steganography. You first need to select the carrier file and then the file that you want to hide. Finally hide it with a password.
Xion Steganography, QuickStego, SlientEye, Image Steganography, Hide in picture and Steghide are few more free Steganography software available in the market for free.
In Steganography, anybody can simply view the carrier file and not knowing the fact that, there is a hidden file in that file or will not suspect that the file which he is viewing, contains any hidden data. Moreover, even if someone suspects that the there is a hidden file in that particular file, he/she wouldn’t be able to view the hidden file as it is password protected.
Steganography techniques were developed for secure communication, but the unlawful persons have started to use them to perform illegal actions. It can be used in good ways to send and receive files in a safe way where the privacy has to be maintained. This is my point of view on Steganography, what is your opinion? Share your thoughts in the comment section.