外文原文2-一个基于修改后的Logistics映射的图片加密方案外文翻译

2011 Fourth International Workshop on Chaos-Fractals Theories and ApplicationsARM Realization of Storage Device Encryption Based on Chaos and AES AlgorithmChunlei Wang, Guangyi Wang School of Electronics Information Hangzhou Dianzi UniversityHangzhou, Chinae-mail: Yue Sun and Wei ChenSchool of Electronics Information Hangzhou Dianzi University Hangzhou, Chinae-mail: AbstractIn order to improve the security of the private information in memorizer, an encryption algorithm, which inherits the advantages of chaotic encryption, stream cipher and AES algorithm, is proposed in this paper. We design and realize an encryption system based on the algorithm on ARM(S3C6410), which can encrypt and decrypt theshow how it generates the keys. The equation (1) gives the switch hyperchaos as below:dxdt a( y x)dyinformation in many kinds of memorizers, such as UDisk, SD card and mobile HDD. The system that uses Human-ComputerInteraction and Visualization technology provides several encryption algorithms and key generators. Some analysis results are presented to show its high security at the end of the paper.dt dS (x)x cy xz udz xy bzdtdukxdt(1)Where a, b, c, d and k are constant parameters.Keywords-chaos; stream cipher; AES; ARM; storage device When x 0 , S (x) 1 ; while S (x) 0 when x 0 .Take the parameters a 35 , b 3 , c 20 , d 5 andI. INTRODUCTIONWith the development of the digital devices, computers and networks, our world relies more and more on the digital data. In many cases, storing data safely is a very big concern. These data have to be protected so as to prevent the possible unauthorized access. Many technologies have been used to improve the security of the data storage. Such as authentication, audit trail and access control 1. But all of these models have not encrypted the original data, once the HDD is accessed, the information in it can be possessed by the invader.In this paper, we designed and implemented an encryption system to encrypt the stored data based on ARM (S3C6410). The PN sequences with good properties aregenerated from chaotic map and the system provides two kinds of encryption algorithm, one is stream cipher with Xor operation 2, the other is a hybrid algorithm of AES and chaos3-7. And we have tried our best to improve the speed of encryption and security.The advantages of this encryption system are as below: 1) it is more secure and complex than software encryption and security chip; 2) it provides two chaotic systems to generate PN sequence and three algorithms to encrypt source data; 3)the values of parameter of chaos maps can be input by user to guarantee the security of the system.II. GENERATION OF CHAOTIC STREAM CIPHERA. Generation of chaotic sequenceThe key of stream cipher can be generated from different chaotic maps. We take a switch hyperchaos as an example to978-0-7695-4560-8/11 $26.00 2011 IEEE DOI 10.1109/IWCFTA.2011.55183k 5 , the system (1) is chaotic and value of the four Lyapunov exponents are 1.4725, 0, -0.0396 and -22.4606. The chaotic attractors are shown in Fig. 1 and Fig. 2 .Figure 1. Attractor onto x-y plane.Figure 2. Attractor onto x-z plane.Now, we discuss the digital implementation of system (1). At first, continuous system (1) can be transformed into a discrete system by following transition:0Universal 0.948298 0.9910ApproximateEntropy 0.844641 0.9900RandomExcursions 0.412739 0.9865RandomExcursionsVariant 0.429472 0.9903Serial 0.198495 0.9925LinearComplexity 0.727851 0.9910un1 nn2 n(k 1)n 2 bThat is.dxi dt f x1 , x2 ,xN lim0xi (n 1) xi (n) . (2)xi (n1) xi (n) f x1(n) , x2(n) , xN (n) , (3)where i = 1, 2, 3. Let xn x1n , yn x2n , zn x3n ,switched system (1) can be dispersed asx( n1) xn a yn xn y(n1) yn + -dS(xn )xn cyn xn zn un z(n1) zn xn yn bzn u (kx )(4)From table we can see that the chaotic sequence generated from switched chaos has very good performance.III. ENCRYPTION ALGORITHM IMPLEMENTATIONDiscrete system (4) has the same dynamic characteristic with system (1) when is small enough, where we take0.001 .In digital system, each variable value of equation (4) for per iteration, xn, yn, zn and un can be expressed by binary data. Taking xn as example, one hasA. Software and hardware configuration:As we know， the efficiency of data encryption is very important, so we need a processor with high computation speed. In this paper, the configuration of the CPU is 667MHZ/128Mbyte and the hardware modules dispose as Fig. 3:xn b1n 2k b 2k 1 b 20 (5)b(k 2)n 1 (k 1l ) n 2lIn order to obtain digital PR sequence, the coefficient bjn for fixed j ( j=1, 2, 3, , k+1+l), can be extracted from the decimal part of equation (5) as the PR sequence and then a PR sequence, bj1bj 2bj 3 bjn , is obtained. If we simultaneously extract multi-coefficients, i.e. multi- digits from (5), the multiple pieces of PR sequences can be also obtained.B. Performance test for the sequenceIn order to show the performance of the chaotic sequence generated by equation (1), we use NIST to test it. NIST is the most authoritative stands in the world to test the randomicity of sequence. The test report for the equation (1) is shown in table . The value of PROPORTION gives therate of passed element.TABLE I. NIST TEST FOR THE SEQUENCEFigure 3. The hardware modules.In the encryption system, the software is based on Qt platform and the main work to do is the software designation based on Qt/Embedded library. The software modules of the system disposes as Fig. 4 and the procedure of it is shown in Fig. 5. The software has login and function GUI(Graphical User Interface), they are presented in Fig. 6 and Fig. 7:Testing Name P-value PROPORTIONFrequency 0.062821 0.9960BlockFrequency 0.392456 0.9870CumulativeSums 0.399723 0.9915Runs 0.339271 0.9910Longest Run 0.242986 0.9850Rank 0.062427 0.9930FFT 0.000000 0.9990NonOverlappingTemplate 0.282626 0.9900OverlappingTemplate 0.548314 0.9830Figure 4. The software modules.1B. Transformation of the storage dataThere are many kinds of memorizer and different memorizers need different interfaces. In this paper, the memorizers to encrypt are USB memorizers and SD card. So the transformation of the system involves USB and SPI transport protocols. They are included in linux and the only thing we need to do is insert the related module into the operation system.C. Encryption algorithms analysisThere are three different algorithms provided in the system, that is, stream cipher based on chaotic sequence and two AES algorithms based on chaotic sequence.1) Stream Cipher: this algorithm is implemented by bit- computation between chaotic sequence and plain text. In this system, the chaotic sequence changes one time after every encryption operation. And the procedure can be described as Fig. 8:Figure 5. The software procedure.Figure 6. The login GUI.Figure 7. The function GUI.Figure 8. Procedure of Stream Cipher.2) AES based on chaotic sequence3-7: The two main operations of AES algorithm are compositor and replacement. There are several different ways to finish the both operations and the basic computation are: substitute bytes, shift rows, mix columns and add round key. Fig. 9 gives an example of AES algorithm, whose secret key is 128 bits. Two kinds of encryption algorithms based on AES are proposed in this paper.Figure 9. AES algorithm2Encryption algorithm Encryption speed (M/min) Decryption speed (M/min)Stream Cipher based on chaos 23.72 38.10Using chaotic sequence as the key of AES 5.87 5.05Using chaotic sequence as the expand key of AES 5.32 5.18a) Using chaotic sequence as the key of AES: In this algorithm, we just replace the original key of AES with the chaotic sequence and dont change anything else. And the sequence changes one time after every 128 bit plaintext having been encrypted. As we know, the security of encryption system relies on the property of the secret keys. In this way, the security of the encryption system is much better than the original AES encryption system.b) Using chaotic sequence as the expand key of AES: In this way, the relativity between the keys can be decreased and the security of the AES encryption system can be improved.IV. APPLICATION IN TEXT ENCRYPTIONIn order to present the performance of this encryption system, we take the text encryption based on the system for example. The chaotic sequence used in this experiment is generated from equation (1). The three different encryption algorithms have the same initial conditions. The condition is that a=35, b=3, c=20, d=5, k=5 and x=1.0, y=1.0, z=1.0, u=1.0. Fig. 10 shows the plaintext, and Fig. 11, Fig. 12 and Fig. 13 show the ciphertext, respectively, encrypted by the above three different algorithms.Figure 10. PlaintextFigure 11. Ciphertext of Stream Cipher.Figure 12. Ciphertext of Using chaotic sequence as the key of AES.Figure 13. Ciphertext of Using chaotic sequence as the expand key of AES.V. PERFORMANCE ANALYSIS OF THE SYSTEMA. Speed of encryptionAn experiment is done to test the speed of encryption. The target to encrypt is a PDF file, whose size is 7.1M. The values given by the table are the average speed of many test results.TABLE II. TEST RESULTS3B. Security of the encryption system1) Using the unattached encryption device based on ARM instead of designing software on PC.2) A login GUI is designed to prevent unauthorized user from invading.3) Several different chaos maps and encryption algorithms are provided to improve the security of this system.4) The values of parameters are set by user, which means that the secret keys are only known by the user himself.VI. CONCLUSIONA modified chaotic map has been proposed in this paper for generating good chaotic sequences in the proposed encryption algorithms.An encryption system based on the algorithms on ARM(S3C6410) is designed and realized, which can encrypt and decrypt the information in many kinds of memorizers, such as UDisk, SD card and mobile HDD. In order to improve the security of the private information in memorizer, three different algorithms are designed, which are stream cipher based on chaotic sequence and two AES algorithmsbased on chaotic sequence. Some figures are given to show the encryption results. It can be seen that all the three algorith