SECRECY OF NOVEL ENCRYPTION ALGORITHMS FOR THE IMAGE CRYPTOSYSTEMS: A REVIEW ARTICLE

Abstract

Straightforward encryption is an efficient way to keep transmitted messages secret. Taking efficiency into account, partial encryption for pictures, audio and video has recently been generally accepted. However, in cases where a large number of images are purposely transmitted to the same destination, a new and efficient method is required. Chang, Hwang and Chen proposed an encryption algorithm for images based on vector quantization, in which the encryption of a common codebook is suggested to be the better option of their two proposed schemes, since several images can be transmitted with only one corresponding codebook encrypted. However, in the present paper, if the popular codebook is used to encrypt a large number of images, the weakness of the CHC image cryptosystem is established according to the selected-plain image assault. And holding the index sets in a simple form is shown not to be a good idea, based on the cypher image-only attack. A way of protecting the transmitted images is also recommended.