• image encryption;
  • chaos;
  • hack;
  • pixel shuffling;
  • NPCR;
  • UACI;
  • MAE


In this article, an algorithm for encryption of digital image based on chaos theory is proposed. This encryption algorithm includes two main operations of image element shuffling and pixel replacement. The analysis of cryptographic strength (resistance attack) has been performed to confirm the fact. The results of several experimental tests, such as key space analysis, key sensitivity analysis, and statistical analysis, show that the proposed algorithm for image cryptosystems provides an efficient and secure way for image encryption and the hacker cannot decrypt an encrypted image without original key. A comparison in terms of correlation between the original and encrypted images, number of pixels change rate, unified average changing intensity, and mean absolute error is performed, which proves that the plain image is very different from the encrypted one. We have also performed fixed point analysis to know how many pixels remain fixed after pixel shuffling operation. Copyright © 2013 John Wiley & Sons, Ltd.