What is Least significant bit algorithm in Information Security?

Least significant bit (LSB) insertion is a common and simple method to embed data in an image file. In this approach the LSB of a byte is restored with an M’s bit. This technique operate well for image steganography. For hiding data within the images, the LSB (Least Significant Byte) approach is generally used.

An image file is a file that shows multiple colors and intensities of light on different location of an image. The best type of image files to hide data inside is a 24 Bit BMP (Bitmap) image.

When an image is of large quality and resolution it is simpler to hide information within image. Although 24 Bit images are best for hiding data because of their size.

Some people can select 8 Bit BMP‟s or possibly another image format including GIF. The reason being is that entry of high images on the internet can rouse suspicion.

The least significant bit i.e. the eighth bit can be used to shift to a bit of the secret message. When it can using a 24-bit image, one can save 3 bits in every pixel by transforming a bit of each of the red, green and blue color element.

Suppose that it can have three adjacent pixels (9 bytes) with the RGB encoding.

10010101 00001101 11001001

10010110 00001111 11001011

10011111 00010000 11001011

When the number 300, the binary description is 100101100 installed into the least significant bits of this element of the image. If it can cover these 9 bits accomplished the LSB of the 9 bytes raised and it can receive the following (where bits in bold have been modified)

10010101 00001100 11001000

10010111 00001110 11001011

10011111 00010000 11001010

Therefore the number 300 was embedded into the grid, only the 5 bits required to be transformed according to the embedded message. On average, only half of the bits in an image will required to be changed to hide a secret message using the maximum cover size.

The LSB algorithm

  • It can choose a cover image of size M*N as an input.

  • The message to be hidden is embedded in RGB element only of an image.

  • It can need a pixel selection filter to acquire the best location to hide information in the cover image to acquire a better cost.

  • The filter can be used to Least Significant Bit (LSB) of each pixel to conceal record, leaving most significant bits (MSB).

  • After that Message is hidden utilizing Bit Replacement method.

GIF images can also be used for LSB steganography, although more care must be taken. The problem with the palette method used with GIF images is that should one change the least significant bit of a pixel, and it can result in a completely multiple colour because the index to the colour palette is modified.

If adjacent palette entries are same, there can be little or no noticeable change, but it should the adjacent palette entries be very diverse, the change can be evident.

Updated on: 11-Mar-2022

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