Chaos-based modified ???EzStego??? algorithm for improving security of message hiding in GIF image

摘要

EzStego is a steganography algorithm to embed the secret message in the GIF images. The message is embedded into indices of sorted color palette of the images. EzStego is a sequential embedding type of stego-algorithm. There is no key required for embedding, so anyone that know the algorithm can extract the message. For improving security, a modified EzStego algorithm is proposed. Bits of the message are embedded randomly in the image. Locations of embedding is generated from a random permutation which need an initial value as stego key. Before embedding, the message is encrypted with random bit which is generated by a chaos map. Based on experiments, the modified EzStego is more secure than the original EzStego, because anyone who has no information on the key can not extract the message from the stego-images.