Image Steganography Review

3 Difference between Encryption and Steganography Encryption and steganography differ in purpose, but are techniques with the same purpose of sending secret data in a way that the intended recipient can not read. Encryption changes the content of the file so that it can not be read, but steganography hides the viewer from recognizing that the message has been exchanged by the media. Using two technologies together makes it very easy to perform secret communications [3].

Steganography is the process of hiding certain data in other data. An example is hiding an image in another image. The main difference between encryption and steganography is that steganography does not seem to change the image, so it is not carefully inspected or analyzed by intermediaries. Figure 0 shows a general steganography framework. It consists of two inputs, a secret image and a cover image. Image of secret image hidden. The cover image is an image that needs to "overwrite" the secret image. These two inputs produce an output image through several hidden algorithms. The output should look exactly the same as the image on the cover page, but if you use the display algorithm, a secret image will be generated.

Image steganography is about the limited ability to use human visual system (HVS). Within reasonable scope, anything that can be embedded in plaintext, ciphertext, other images, or bitstreams can be hidden in the image. In recent years, along with the development of high-speed and powerful graphic computers, image steganography has greatly improved, and steganographic software can now be provided to everyday users via the Internet. Information can be hidden in the image in various ways. In order to hide the information, it is possible to encode any information in the message by inserting the message directly, select messages in the "noisy" area (area where there are many natural color changes) which does not attract attention You can embed it. This message may be randomly scattered throughout the image. In redundant mode, use the message that encoded the cover image of "wallpaper"

By definition, the visible watermark is not steganography. The main difference is one of the intentions. Traditional steganography hides information, watermark expands information and becomes attribute of cover image. The digital watermark may contain information such as copyright, ownership, license, etc. In steganography, the purpose of communication is hidden information. In electronic watermarking, the purpose of communication is cover. Masking is more robust than LSB insertion in compression, trimming, and some image processing. Masking technology embeds information in a more important area, so it can be applied not only to covering hidden messages at "noise" level but also to cover images completely. This is better than LSB containing irreversible JPEG images.