提出了一種基于級聯混沌系統的圖像加密算法。實驗結果表明，這種加密算法具有高度的安全性和有效性。關鍵詞： 圖像加密算法；混沌；級聯混沌 目前混沌加密己成為密碼學研究的熱點之一，但已有的大部分混沌加密算法都是基于單個混沌系統的。事實表明，一些混沌映射可通過相空間重構的方法精確預測出來[1]。另外，由于計算機精度的限制，單混沌系統輸出的時間序列并不能達到理論上的完全隨機，而可通過多個混沌系統的級聯使
138 2002 G DCT K L P(M/K)(NIL). P S DCT (M/K)(N/L)], i=h,j= G[0,1 G Sm=88(k=1,2,,M/8 Sign(nn) ⅠB.IBI lB y DCT 2,,M/K,j=1,2,,N/L),IB=j+(-1)(N [O,1,,31 L). IP ⅠP 3.3 K L) Stepl IBi= p Immage 3.2.3 Outl mage Inl mage Step2.(1 k(k=1, Out/ mage yh Skm DCt ep2.(1) rk yk(= 1, g km 10. 88 DCT JPE G P G DCT IPE JPEG 3.2.4 3.3 JPEG MPEG, JPEG x0=0.60773).2 en a DCT x0=0.60773) Huffman [2,8] JPEG 1d.2d 0=0.60772 S G 3 DCT 3a,3b 3 c JPEG 90 DCT DCT a Lena原圖 b加密圖像 c解密恢復的圖像d密鑰錯誤解密的圖像 1994-2012 China academic journ圖Hlec圖像筐國咖密解密鋪果. All rights reserved.htt:ww. cnkinet 139 B enn 原圖 b加密圖像 c解密恢復的圖像d密鑰錯誤解密的圖像 圖2圖像域加密與解密結果 a隨機噪聲 b均勻噪聲 C JPEG壓縮 圖3加密圖像的失真對解密圖像的影響 [4] C Shi, B Bhargava. Light -w eight M PEG video encr yption a gorithm Al. In: Pr oc ee dings of the Int ernat ional Conference Delhi, India, 1998. 55 6 [5 Josef Scharinger. Fast en cry pt ion of image dat a usin g ch aot i Kolm og or ov flows[A]. In: Proceedings of E lectronic Imaging 97, Security and Watermarking of Multimed ia Con ten ts, S an Jos e,1997,3022:278289 [6 Qi Don gxu, Zou Jiancheng. et al. New scramble tr ans form a- tion and applic at ion in inform at ion hiding[ J]. Ch inese Science (E),20,030(5):440447( in chinese) E),2000,30(5):440447) [1 Li Y uh uan. Comb inat orial Mathem at ics[ M I. Beijing: Beijing [7] Hui Xiang, et aL. D igital water ark ing sys tems w ith ch ic Normal College press, 1998( in Chinese) sequences[ A]. In: Proceedings of Electronic Imaging99, Se- M ,1998) cu rity and Waterm ark ing of Multimedia Contents, SPIE, San [2] Wu M insh eng, Wang Jiesheng. L iu Shen quan. Perm ut at ion Jose,1999,3657:449457 transformation of image[ J]. Chinese Journal of Computers, [8] Yi Kaixiang, Sun Xin, Shi jiaoy ing. Chaotic sequences bas ed 1998,21(6):514519 in chines e) image encry pt ion alg or ith m[ J]. Journ al of Computer-A ided Des ign Com puler Graph ics, 2000, 12(9):672 676(in Chi- 1998,21(6):514519 lese Wei, Qi Don gxu. Digit al image tran format ion and in- format ion hiding and dis guisin g techn ology[ J]. Chin ese Jour 2000,12(9):672 nal of Computers, 1998, 21(9):838 843( in Chinese 676) 1998,21(9):838843) o1994-2012ChinaAcademicJournalElectronicPublishingHouse.Allrightsreservedhttp://www.cnki.net