“Comparative Analysis of Double Image Encryption Schemes: Arnold Cat Map-Blowfish and Arnold Cat Map-TEA”

Abstract

Security of digital images becomes an important issue with the rapid growth of digital communication and multimedia applications due to the development of the communication of digital products through networks which occurs frequently. Recent cryptography algorithms are providing essential techniques to protect information and multimedia data from unauthorized access. In this study double image encryption based on chaos image encryption and block cipher encryption are implemented and analyzed with different parameters like NPCR, UACI, correlation-coefficient, histogram and encryption speed to measure the strength of algorithms. The average value of NPCR for Arnold Cat Map-Blowfish and Arnold Cat Map-TEA are 99.87008837 and 99.87275865 respectively. The average correlation value of Arnold Cat Map-Blowfish and Arnold Cat Map-TEA are -7.97E-07 and -1.89E-06 respectively. The average encryption time of Arnold Cat Map-Blowfish and Arnold Cat MapTEA

is 69.56 ms and 73 ms respectively. Similarly, the average decryption time of Arnold Cat Map-Blowfish and Arnold Cat Map-TEA is 69.44 ms and 72.89 ms respectively. The average value of UACI for Arnold Cat Map-Blowfish and Arnold Cat Map-TEA are 28.1520017 and 27.1723318 respectively. Hence, on the basis on NPCR and correlation coefficient Arnold Cat Map-TEA has better performance while on the basis of computational time and UACI Arnold Cat Map-Blowfish showed better performance. Arnold Cat MapBlowfish and Arnold Cat

Map-TEA both have greater difference in histogram of cipher and plain image so both strategies have strong impact on histogram analysis.

Keywords: Image encryption, Chaos encryption, Block cipher, Arnold Cat Map, Blowfish, Tiny Encryption Algorithm.