Fig. 1. Flowchart of the proposed algorithm. (a) Encryption process; (b) decryption process

Fig. 2. Tested images. (a) Lena; (b) Elephant; (c) Grnpeace; (d) Peppers; (e) Butterfly

Fig. 3. Results of encryption and decryption. (a) Cipherimages; (b) restituted images

Fig. 4. Histogram results. (a) Plaintext images; (b) ciphertext images

Fig. 5. Correlation distribution of adjacent pixels. (a) Lena's plaintext image; (b) Lena's ciphertext image

Fig. 6. Results of chosen-plaintext attack. (a) Fake plaintext images; (b) decrypted results of Fig.3(a)

Fig. 7. Decrypted results using a slightly deviated key. (a) a; (b) b; (c) c; (d) x'₀

Fig. 8. Decrypted results when the intensity of Gaussian noise is 1. (a) Proposed algorithm; (b) algorithm in Ref.[16]; (c) algorithm in Ref.[17]

Fig. 9. Average PSNR and CC under Gaussian noise attack. (a) PSNR; (b) CC

Fig. 10. Decrypted images under cropping attack(η=20%). (a) Proposed algorithm; (b) algorithm in Ref.[16]; (c) algorithm in Ref.[17]

Fig. 11. Average PSNR and CC under cropping attack. (a) PSNR; (b) CC