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An improved piecewise linear chaotic map based image encryption algorithm.

Hu Y, Zhu C, Wang Z - ScientificWorldJournal (2014)

Bottom Line: The order of processing pixels is not in accordance with the index of pixels, but it is from beginning or end alternately.The cipher feedback was introduced in diffusion process.Test results and security analysis show that not only the scheme can achieve good encryption results but also its key space is large enough to resist against brute attack.

View Article: PubMed Central - PubMed

Affiliation: School of Information, Guangdong University of Finance & Economics, Guangzhou 510320, China.

ABSTRACT
An image encryption algorithm based on improved piecewise linear chaotic map (MPWLCM) model was proposed. The algorithm uses the MPWLCM to permute and diffuse plain image simultaneously. Due to the sensitivity to initial key values, system parameters, and ergodicity in chaotic system, two pseudorandom sequences are designed and used in the processes of permutation and diffusion. The order of processing pixels is not in accordance with the index of pixels, but it is from beginning or end alternately. The cipher feedback was introduced in diffusion process. Test results and security analysis show that not only the scheme can achieve good encryption results but also its key space is large enough to resist against brute attack.

Show MeSH
(a) NPCR for 100 modified plain-image Cameraman; (b) UACI for 100 modified plain-image Cameraman.
© Copyright Policy - open-access
Related In: Results  -  Collection


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fig5: (a) NPCR for 100 modified plain-image Cameraman; (b) UACI for 100 modified plain-image Cameraman.

Mentions: We have done plaintext sensitivity analysis (differential analysis) by calculating the NPCR and UACI for plain-image Lena, Sailboat, Pepper, and Cameraman. In particular, we have randomly chosen 100 different pixels (one at a time, including the very first and very last pixels of the image) in each plain-image and changed their values slightly, and then we have computed NPCR and UACI for all the cases using (8). The results of NPCR and UACI for the plain-image Cameraman are shown in Figures 5(a) and 5(b), respectively. It is clear that the NPCR and UACI values remain in the vicinity of the expected values (shown by the horizontal lines); that is, the proposed image encryption technique shows extreme sensitivity on the plaintext. Also, Table 3 shows the average values of NPCR and UACI for the plain-image Lena, Sailboat, Pepper, and Cameraman. We can find that the mean NPCR is over 99% and the mean UACI is over 33%. The results show that the proposed algorithm is very sensitive to tiny changes in the plain image; even if there is only one bit difference between two plain images, the encrypted images will be different completely. Thus, the algorithm is robust against differential attack.


An improved piecewise linear chaotic map based image encryption algorithm.

Hu Y, Zhu C, Wang Z - ScientificWorldJournal (2014)

(a) NPCR for 100 modified plain-image Cameraman; (b) UACI for 100 modified plain-image Cameraman.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3921974&req=5

fig5: (a) NPCR for 100 modified plain-image Cameraman; (b) UACI for 100 modified plain-image Cameraman.
Mentions: We have done plaintext sensitivity analysis (differential analysis) by calculating the NPCR and UACI for plain-image Lena, Sailboat, Pepper, and Cameraman. In particular, we have randomly chosen 100 different pixels (one at a time, including the very first and very last pixels of the image) in each plain-image and changed their values slightly, and then we have computed NPCR and UACI for all the cases using (8). The results of NPCR and UACI for the plain-image Cameraman are shown in Figures 5(a) and 5(b), respectively. It is clear that the NPCR and UACI values remain in the vicinity of the expected values (shown by the horizontal lines); that is, the proposed image encryption technique shows extreme sensitivity on the plaintext. Also, Table 3 shows the average values of NPCR and UACI for the plain-image Lena, Sailboat, Pepper, and Cameraman. We can find that the mean NPCR is over 99% and the mean UACI is over 33%. The results show that the proposed algorithm is very sensitive to tiny changes in the plain image; even if there is only one bit difference between two plain images, the encrypted images will be different completely. Thus, the algorithm is robust against differential attack.

Bottom Line: The order of processing pixels is not in accordance with the index of pixels, but it is from beginning or end alternately.The cipher feedback was introduced in diffusion process.Test results and security analysis show that not only the scheme can achieve good encryption results but also its key space is large enough to resist against brute attack.

View Article: PubMed Central - PubMed

Affiliation: School of Information, Guangdong University of Finance & Economics, Guangzhou 510320, China.

ABSTRACT
An image encryption algorithm based on improved piecewise linear chaotic map (MPWLCM) model was proposed. The algorithm uses the MPWLCM to permute and diffuse plain image simultaneously. Due to the sensitivity to initial key values, system parameters, and ergodicity in chaotic system, two pseudorandom sequences are designed and used in the processes of permutation and diffusion. The order of processing pixels is not in accordance with the index of pixels, but it is from beginning or end alternately. The cipher feedback was introduced in diffusion process. Test results and security analysis show that not only the scheme can achieve good encryption results but also its key space is large enough to resist against brute attack.

Show MeSH