Steganography is the art of hiding secret messages within a larger image or message such that the hidden message is undetectable without the correct key. Our project deals specifically with hiding written codes in images.
There are many different purposes that one might have to hide information in picture. One application, called watermarking, can serve to authenticate an image. In watermarking, changing the watermark will seriously effect the image, but if the image is altered in any way the watermark stays. In other words the watermark does not disappear. This can be used to copyright images or documents to disable the ability to alter them.
Our project uses a robust data hiding scheme. This means that the purpose of the scheme is to allow an image to pass through a significant amount of noise, in our case the printing an scanning process. Other types of steganography use a fragile data hiding scheme which makes the encoded message disappear if the document is altered in anyway. This allows one to check if the picture was altered by making sure the coded message is still present. Our project looks at a specific data hiding technique that we believe is highly applicable.