[EN] Hiding Data In An Image (LSB Technique)
Nowadays hiding data is significant. It is important for blocking other, unwanted people to read/learn that data or information. Cryptography is mixing, confusing characters and making it unable to read and hiding something inside of a file/folder, making it hidden/secret means steganography. Let’s move on!
What Is Steganography And How It Works?
Steganography is a greek origin word and it means “hidden data”.The purpose here is that people other than the sender and receiver are not aware of this message. This is the main difference between stego and cryptography. Also it is possible to hide data inside of picture, video and audio files.
There are so many ways to hide data inside of a file. These are some of them;
Echo Data Hiding Least Significant Bit (LSB) Coding Phase Encoding Parity Coding Spread Spectrum
The important point here is, someone other than sender and receiver shouldn’t see any changes otherwise there may be bad consequences. So in this topic I’m going to touch on LSB technique. Using this tecnique, sender makes changes in the lowest value bits of the bytes in the pixels of the picture. These pixels represent the color in the picture. The method of adding these colors to the least significant bit is called (LSB – Least Significant Bit Insertion Methods). In order to make a change in the lowest value, human eye cannot see the difference between them.
LSB (Least Significant Bit Insertion Methods)
It is a widely used technique. The logic here is the way of adding the bits of the data we want to hide sequentially from the beginning to the least important bit of each byte value in the pixels that make up the picture. In addition it causes data loss when used incorrectly.
For instance; (A == 01000001)
10101101 10100101 10101100 11010100 10001010 11001001 10011001 11001100
10101100 10100101 10101100 11010100 10001010 11001000 10011000 11001101
As you can see, the binary equivalent of the letter A is added to the final values of the bits from right to left. You can see that it is added in order here. Tertiary people will be able to solve this easily.
I would also like to tell you about a tool that you can use LSB automatically. Its name is OpenPuff. You can add data to the image file with the password you set.
You must enter the password you set in the Cryptography A section. Then you need to add your picture by clicking the Add button at the bottom. You need to remove the Enable (B) and (C) marks and add the data that you will hide to the Target section.
It will extract the data hidden in the directory you specify.
Hope you enjoyed it. Have a nice day, take care 🙂
Translated from: https://pwnlab.me/tr-resmin-icine-veri-eklenmesi-lsb-mantigi/