Controlled partial image encryption based on LSIC and chaotic map

Partial image encryption plays a vital role in the field of medical image encryption, because small amount of encryption leads to high security with low computation complexity. This paper presents controlled partial image encryption using LSIC and chaotic map. It consists of two methods. In method-1 image is divided into 16x16 blocks. Entropy of each block is compared with threshold entropy from entropy selection table. If entropy of each block is greater than predefined threshold entropy then that block is XORed with 16x16 random block generated by converting each row of LSIC into 16x16 block. In method-2 entropy of block greater than predefined threshold entropy then pixels within that block is shuffled using chaotic map. Based on different threshold entropy values different partial encrypted images are obtained. From the experimental results shows that proposed methods can controlled amount of encryption as per the requirements.