Image Steganography: LSB Technique

A digital colour image is made up of pixels. Each pixel stores three colour channel values: Red, Green, and Blue, each ranging from 0 to 255 and stored in one byte. A 1000x1000 pixel image therefore contains three million individual bytes of colour data. This large volume of data creates room for hiding small amounts of additional information without visible change.

In an 8-bit value, the least significant bit contributes only 1 to the value when set, compared to 128 for the most significant bit. Flipping the LSB of a colour channel changes a pixel value by at most 1 out of 255, a change completely imperceptible to the human eye. This makes the LSB the ideal location for embedding hidden bits without degrading visible image quality.