Hiding data in indexed images

In this paper, a method for hiding data is proposed based on color table expansion technique for indexed images. At the same time the security and the hiding capacity are analyzed in great detail. The analytic results show that this method has very strong security and very high hiding capacity. Secret data can be hidden in a stego-image which has exactly the same visual effect as the original image. If the correct key is used, these confidential data can be recovered from the stego-image without distortion. In addition, due to the use of random numbers, the statistical properties of the confidential data are completely overshadowed, and the stego-image is independent of those confidential data.