This Project Describes the use of LSB Steganography.
Do check the python script written to implement lsb steganography
#./stego -f <filename.png> -e <secret_message> -p <Password (Optional) > : To embed a secret message.
#./stego -f < secretfile.png > -x -p < Password supplied > : To extract the secret message.
#Note : Even if you passed a blank field in the -p argument,while creating a secret file, you must append a -p while extracting the message.
STEGANOGRAPHY comes from the Greek Words: STEGANOS – “Covered”, GRAPHIE – “Writing”.
The sender hides his/her message within an image/audio/video.Since the algorithm uses the lease significant bit to hide the secret message the change is undectable by a naked eye.
The various types of steganography include:
- Image Steganography
- Audio Steganography
- Video Steganography
- Text files Steganography
Types of Images:
- Black and white
- Geryscale
- RGB
In a gray scale image each pixel is represented in 8 bits. The last bit in a pixel is called as Least Significant bit as its value will affect the pixel value only by “1”. So, this property is used to hide the data in the image. If anyone have considered last two bits as LSB bits as they will affect the pixel value only by “3”
The LSB embedding approach has become the basis of many techniques that hide messages within multimedia carrier data. LSB embedding may even be applied in particular data domains – for example, embedding a hidden message into the color values of RGB bitmap data
In a Greyscale image, each pixel is represented by 8 bits, while in a RGB it is 24 bits
Suppose the following are some of the bits in a Grayscale image
11110011
11011011
10110110
11011100
11011111
11010111
00100110
01000011
The algorithm simply replaces the last bit of the bytes with the consecutive bits of the letter "A", Giving us
11110011
11011010
10110110
11011100
11011110
11010110
00100110
01000011
Steganalysis is the study of detecting messages hidden using steganography
LSB Steganography can be detected by looking at the histograms of the files
Also lossy compression technique can render LSB Steganography useless to an extent, so lossless compression techniques should be used