Encryption Quality Measurement
of a Proposed Cryptosystem Algorithm for the Colored Images Compared with Another
Algorithm
Osama Abu Zaid1, Nawal El-Fishawy2
and Elsayed Nigm1
1Department of Mathematics,
Zagazig University, Egypt
2
Department of Computer Science and Engineering, Menoufia University, Egypt
Abstract: In this paper, a proposed cryptosystem algorithm based on two different
chaotic systems is presented. The proposed cryptosystem algorithm is designated
as PCACH. A recently developed encryption algorithm which is designated here as
HuXia is reviewed. These two algorithms are applied to three images of
different color frequencies, i.e., different types of colored-images are
encrypted with each of the two encryption algorithms. Both of them are applied to
the different images with two different types of encryption modes, Electronic
Code Book (ECB) and Cipher Block Chaining (CBC). Visual inspection is not sufficient
to assess the quality of encryption so other measuring factors are considered
based on measuring the maximum deviation and the correlation coefficient
between the original and the encrypted images. For judging the force of
security, we measure the plain-text sensitivity by using NPCR and UACI analysis,
measuring information entropy and measuring the key sensitivity. Also, the
encryption/decryption time and the throughput are measured for the two
algorithms. The results suggest that PCACH is a very good algorithm and superior
to HuXia.
Keywords: Encryption algorithms, image encryption, quality measurements, modes of encryption.
Received April 10, 2013; accepted June 23, 2013