Inter national J our nal of Electrical and Computer Engineering (IJECE) V ol. 8, No. 6, December 2018, pp. 4577 4583 ISSN: 2088-8708, DOI: 10.11591/ijece.v8i6.pp4577-4583 4577       I ns t it u t e  o f  A d v a nce d  Eng ine e r i ng  a nd  S cie nce   w     w     w       i                       l       c       m     Domain Examination of Chaos Logistics Function As A K ey Generator in Cryptograph y Alz Danny W o w or 1 and V ania Beatrice Liwandouw 2 1 Department of Informatics Engineering, Satya W acana Christian Uni v ersity , Salatig a, Indonesia 2 Department of Computing Science, Radboud Uni v ersity , Nijme gen, The Netherland Article Inf o Article history: Recei v ed September 28, 2017 Re vised May 09, 2018 Accepted May 22, 2018 K eyw ord: Domain Examination Logistic Function Chaos Cryptograph y ABSTRA CT The use of logistics functions as a random number generator in a cryptograph y algo- rithm is capable of accommodating the dif fusion properties of the Shannon principle. The problem that occurs is initialization x 0 w as static and w as not af fected by changes in the k e y , so that the algorithm will generate a random number that is al w ays the same. This study design three schemes that can pro viding the fle xibility of the input k e ys in conducting the e xamination of the v alue of the domain logistics function. The results of each schemes do not sho w a pattern that is directly proportional or in v erse with the v alue of x 0 and relati v e error x 0 and successfully fulfill the properties of the b utterfly ef fect. Thus, the e xistence of logistics functions in generating chaos numbers can be accommodated based on k e y inputs. In addition, the resulting random numbers are dis- trib uted e v enly o v er the chaos range, thus reinforcing the algorithm when used as a k e y in cryptograph y . Copyright c 2018 Institute of Advanced Engineering and Science . All rights r eserved. Corresponding A uthor: Alz Dann y W o w or Af filiation F aculty of Information T echnology , Satya W acana Christian Uni v ersity , Jl. Dipone goro 52-60, Salatig a 50711, Indonesia +62852 0071 0079 alzdann y .w o w or@staf f.uksw .edu 1. INTR ODUCTION The logisti c function f ( x ) = r x (1 x ) or in the iterati v e form x i +1 = r x i (1 x i ) w as usually used as a generator in the generation of chaos-based random numbers [1]. This function is able to accommodate the dif fusion properties of Shannon’ s principle on cryptograph y algorithms, since the y ha v e a sensiti vity to initial v alues. Research [2], [3], [4], uses numbers as static initialization on logistics functions in cryptograph y algo- rithms. This means that changes to the k e y don’ t ha v e an ef fect on random numbers, thus the algorithm will still acquire a random number that is al w ays the same. Research [5], also uses numbers as input v alues that directly fill in by user , ne v erthele ss becomes inef ficient since the user needs more input other than the k e y and plainte xt. This research not only combines algorithms such as [6], [7], [8], b ut designs a ne w algorithm to obtain an unique k e y . Additionally , the function will generate a random number , if the initialization domain r and x 0 as seed is limited to a certain v alue, 0 < x 0 < 1 , and r = 4 . The v alue of r is constant, making the strength of the algorithm rests on the v alue of x 0 . Moreo v er it needs an e xamination process by using an y scheme that can increase x 0 comple xity space, on the contrary remain in logistics function domain. This study pro vides the fle xibility of k e y inputs that are ef ficient and can generate dif ferent random numbers of logistics functions. J ournal Homepage: http://iaesjournal.com/online/inde x.php/IJECE       I ns t it u t e  o f  A d v a nce d  Eng ine e r i ng  a nd  S cie nce   w     w     w       i                       l       c       m     Evaluation Warning : The document was created with Spire.PDF for Python.
4578 ISSN: 2088-8708 2. PR OPOSED EXAMIN A TION SCHEME The e xamination process of the logistics function domain conducted to a wide v ariety of inputs that allo w it to be used as a k e y . Suppose the k e y k 1 ; k 2 ; : : : ; k 8 is the result of a con v ersion of eight ASCII characters. K e y input is set up to eight characters, considering the user’ s ability to recall k e y and also consider the comple xity of the k e y guessing space when the use of the characters too little. Each k e y input of l ess than eight characters, then do the padding process with character x that equi v alent to 167 in ASCII. This study pro vides three algorithms that are used for the e xamination process of initialization v alue in domain 0 < x 0 < 1 , as sho wn in the general scheme in Figure 1. The ratio of r a is designed as a comparison of tw o v alues to accommodate the domain from initialization. Let r a = p a =q a where q a > p a , for a = 1 ; 2 ; 3 and p a ; q a 2 R . x 0 A SC I I   e n c o d e ,    k i ,   i = 1,2,…, 8. examination  scheme r a  = p a /q a a = 1,2,3. m a   key = 8 p a d d i n c h a r a c t e r   “§ Y N Figure 1. General Scheme of x 0 Initialization V alue Determination. 2.1. The First Scheme Gi v en each k i 2 Z 256 for i = 1 ; 2 ; : : : ; 8 is the decimal base number of ASCII con v ers ion results. T o be able to mak e changes at e v ery turn of the input, gi v en inde x v alue d i 2 Z 256 for j = 1 ; 2 ; : : : ; 8 as a constant v alue which is multiplied by the v alue k i . Scheme-1 is determined by using r 1 = p 1 =q 1 where, p 1 = ( k 1 ) 2 + k 7 d 7 + k 3 d 3 + k 4 d 4 + k 5 d 1 + k 6 d 6 + k 8 d 8 + k 1 d 5 (1) q 1 = 8 X i =1 k i = 8 ( k 7 + d 2 ) k 1 d 3 + k 4 d 5 + k 6 d 8 + k 3 d 1 + k 5 d 6 + k 8 d 7 ( k 2 + d 4 ) (2) Determination of p 1 v alue is obtained from the sum of multiplication k i and d i which is performed based on position, it is only for k 1 and d 5 there is crossing position and at k 1 squared. Multiplication of position dif ference is also done to acquire the q 1 v alue, ho we v er in sum with the a v erage v alue of each k i . The multi- plication combination is done as a v ariation to g ain a unique rat io v alue, taking into account the requirement q 1 > p 1 . 2.2. Second scheme Scheme-2 also uses the same decimal number and inde x v alue, where each k i , d i 2 Z 256 for i; j = 1 ; 2 ; : : : ; 8 . The ratio v alue is determined by the equation r 2 = p 2 =q 2 , p 2 = ( k 1 + k 2 + k 3 + k 4 + k 5 + k 6 ) = 6 = 6 X i =1 k i = 6 (3) q 2 = k 1 d 1 + k 2 d 2 + k 3 d 3 + k 4 d 4 + k 5 d 5 + k 6 d 6 + k 7 d 7 + k 8 d 8 = 8 X i =1 k i d i (4) The p 2 v alue is obtained using the a v erage of the first six v alues of k i , whereas to earn the q 2 v alue is the sum of the multiplication of k i and d i v alues according to the order of each v alue. 2.3. Third scheme Ev ery k i ; d j 2 Z 256 for i; j = 1 ; 2 ; : : : ; 8 : Scheme-3 is obtained based on r 3 = p 3 =q 3 , where the determination of the numerator and denominator is gi v en in Equation (5) and Equation (6). The p 3 v alue is the IJECE V ol. 8, No. 6, December 2018: 4577 4583 Evaluation Warning : The document was created with Spire.PDF for Python.
IJECE I SSN: 2088-8708 4579 a v erage of the multiplication k i with d i only at the first v alue, the third v alue, and the sixth v alue with each inde x. p 3 = ( k 1 d 1 + k 2 + k 3 d 3 + k 4 + k 5 + k 6 d 6 ) = 6 (5) q 3 = 3( k 1 d 1 ) + 7( k 2 d 2 ) + 11( k 3 d 3 ) + 13( k 4 d 4 ) + 17( k 5 d 5 ) + 23( k 6 d 6 ) + 6( k 7 d 7 ) + 27( k 8 d 8 ) (6) The v a lue of q 3 is t he sum of the k i and d i multiplications based on the inde x with the constants selected by dif ferent increments. 3. RESUL T AND DISCUSSION 3.1. Analysis of Examination Pr ocess Domain e xamination of the logistics function is performed based on the three schemes gi v en in t he pre vious section. Referring to the general scheme in Figure 1, then testing related v ariations of inputs that allo w to be used as a k e y . Each possible k e y is an ASCII character whose decimal basis is in the range 0 to 255. The problem that occurs is not all numbers ha v e a character . Consequently the test for the lo west number can’ t start from decimal 0 instead in decimal 32 which is proportional to the space character , whereas testing for the lar gest number at decimal 255 is equi v alent to the character . In addition to character testing for minimum and maximum decimals, k e y tests are also tested with one bit dif ference, so that it can be seen ho w sensiti v e each scheme is to generating initialization v alues. T able 1 is the simulation result of each scheme in obtaining the v alue of x 0 . T able 1. K e y V ariations T est on Each Scheme. T est Input K e ys Schem e-1 Scheme-2 Scheme-3 1 ZZZZZZ 0.002416239247 0.020477815700 0.082448573324 2 ZZZZZY 0.002417771534 0.020467836257 0.082481509183 3 fti 0.002441029054 0.024268127467 0.082049869712 4 ftj 0.002439355077 0.024284705051 0.082201209246 5 $4LaT1g4 0.006268369980 0.025188594809 0.095909955612 6 $4LaT1g3 0.006272557467 0.025266127990 0.096168154762 7 (space 8 character) 0.018665158371 0.027777777778 0.096054888500 8  0.003244514742 0.027777777778 0.096054888508 9 y y y y y y y y 0.001456374283 0.027777777778 0.096054888508 T esting with one bit dif ference (numbers 1 through 6) sho ws the changes in v alues that be gin to occ ur in the 4th or 5th mantissa of the x 0 v alue in each schema. Accordingly , the process of domain e xamination for each scheme succeeds to generate dif ferent initialization. This condition corresponds to the need of logistics functions in obtaining random numbers based on chaos. T ests with the same eight-character input based on the smallest decimal, the medium decimal, and the lar gest decimal are gi v en successi v ely in the numbers 7, 8, and 9 in T able 1. The initialization v alues in scheme-2 and scheme-3 obtain the same v alue, although the input is v ery dif ferent. This condition occurs since the determination ratio of r 2 and r 3 using the a v erage process to get the numerator , while for the denominator using the addition and multiplication of characters with the inde x v alue with the same position. On the other hand, scheme-1 uses a combination of multi plicity of position dif ference, squared and mean process. In that case, scheme-1 k eeps generating dif ferent initialization v alues. 3.2. Relati v e Err or T est Relati v e error testing [9] w as conducted to see whether linear character reduction w ould yield also linear results on the x r v alues with proportional or in v ersely proportional. Use E R = j c a p a j =c a 100% , the k e y y y y y y y y y is chosen as the reference v alue c a (number 1 in T able 2), and the approximation v alue as the k e y input p a less than eight characters y (iterated from number 2 to number 8). Domain Examination of Chaos Lo gistics Function As A K e y Gener ator in Crypto gr aphy (Alz Danny W owor) Evaluation Warning : The document was created with Spire.PDF for Python.
4580 ISSN: 2088-8708 T able 2. Relati v e error test on k e y v ariation dif ferences. T est Input k e ys Scheme-1 Scheme-2 Scheme-3 Relati v e Error Scheme-1 Scheme 2 Scheme-3 1 y y y y y y y y 0.00145637428 0.027777777778 0.09605488850 2 y y y y y y y 0.00151184278 0.030084945729 0.10267089320 3.81 8.31 6.89 3 y y y y y y 0.00237830973 0.032442748091 0.10498487627 63.30 16.79 9.30 4 y y y y y 0.00247676219 0.032778687034 0.10922797121 70.06 18.00 13.71 5 y y y y 0.00260130457 0.032743277230 0.11525621373 78.62 17.88 19.99 6 y y y 0.00272929162 0.032262996942 0.11525043975 87.40 16.15 19.98 7 y y 0.00287551307 0.031283195241 0.10350303974 97.44 12.62 7.75 8 y 0.00146481070 0.029781420765 0.09849935979 0.58 7.21 2.54 The relati v e error results in each scheme do not sho w a proportional or in v ersely proportional pattern. So, it will complicate cryptanalyst to see the pattern of input changes on the same character . 3.3. Linear Regr ession T est One-to-one correspondence between the input-output is also important so that cryptanalyst dif ficult to reconstructing scheme and mak e prediction of t he k e y used as input. Thi s relationship can be seen through a linear re gression test based on the rate of change on the resulting v alue of x 0 . Figure 2, is the result of each scheme visualized using the Scatter plot. The diagram of each scheme has no linear relationship, because when the curv e matching process is used, the coef ficient of determination ( R 2 ) is close to zero. This test illustrates that an y changes to the k e y characters is done patterned, will not pro vide an initial v alue x 0 linearly patterned, either proportional or in v ersely . scheme 1 0.000 0.001 0.002 0.003 0.004 0 1 2 3 4 5 6 7 8 y = 9.589E-5x + 0.0018 R ²  = 0.1502 scheme  2 0.026 0.028 0.030 0.032 0.034 0 1 2 3 4 5 6 7 8 y = 0.0002x + 0.0301 R ²  = 0.1 scheme  3 0.080 0.091 0.103 0.114 0.125 0 1 2 3 4 5 6 7 8 y = 0.0007x + 0.1026 R ²  = 0.0567 Figure 2. Diagram Scatter Initialization V alue x 0 based on K e y P attern Changes. 3.4. Butterfly Effect T est The b utterfly ef fect test is used to indicate the change in bits in the k e y input, whether it gi v es a lar ge change to the output. Suppose that as a comparator k e y ZZZZZZ and ZZZZZY are selected which has a dif- ference of one bit. The result of the tw o k e ys with scheme-1 is obtained by a random number of the first 500 iterations, sho wn in Figure 3. ZZZZZZ 0 0.25 0.5 0.75 1 i 0 125 250 375 500 ZZZZZY 0 0.25 0.5 0.75 1 i 0 125 250 375 500 x i x i Figure 3. Results of Random Numbers with Dif ferent Inputs 1 Bit for Scheme-1. V isually , the random number generated is v ery dif ferent although the dif ference in initialization v alue x 0 is only 0 : 0000151538 1 : 538 10 6 or in an absolute relati v e of 0.063%. A minor change in input and a major change in output pro v es that the 1st scheme has successfully fulfilled the b utterfly ef fect. IJECE V ol. 8, No. 6, December 2018: 4577 4583 Evaluation Warning : The document was created with Spire.PDF for Python.
IJECE I SSN: 2088-8708 4581 The initial v alue dif ference of x 0 is 0.0487% in scheme-2. But the rate of change occurs v ery signif- icantly that appears in the Scatter diagram in Figure 4. So, the scheme-2 has also fulfilled the b utterfly ef fect test. ZZZZZZ 0 0.25 0.5 0.75 1 i 0 125 250 375 500 ZZZZZY 0 0.25 0.5 0.75 1 i 0 125 250 375 500 x i x i Figure 4. Results of Random Numbers with Dif ferent Inputs 1 Bit for Scheme-2. Significant changes also occur at random v alues with scheme-3, as sho wn in Figure 5, although the dif ference is 0.0399% at input v alue x 0 . So, the scheme-3 also meets the properties of the b utterfly ef fect. ZZZZZZ 0 0.25 0.5 0.75 1 i 0 125 250 375 500 ZZZZZY 0 0.25 0.5 0.75 1 i 0 125 250 375 500 x i x i Figure 5. Results of Random Numbers with Dif ferent Inputs 1 Bit for Scheme-3. The three schemes ha v e succeeded in fulfilling t he properties of the b utterfly ef fect, thus the e xistence of the logistics function in generating chaos numbers can be accommodated based on k e y inputs. Each scheme can be used as a complement to a cryptograph y algorithm to meet the dif fusion properties of Shannon’ s principle. 3.5. Analysis Of The Algorithm Ability Each scheme is tested in correlation [10], to detect the connectedness of the random number generated based on the input. While MAPE [11], it is used to find out ho w massi v e the dif ference of random v alue of k e y change. Used three v ariations of the input [12], the firs t is the same character input, a second input alphabetic characters that re v olv e around the 26-character alphabet. While the last test, used alphabet , symbols, and numbers. Calculation of correlation in T able 3 sho w that there are tw o v alues on scheme-1 and scheme-3 which correlation is ne g ati v e, besides the rest is positi v e. Cryptographically , the ne g ati v e v alue is not too influential, hence it seen ho w close the v alue to zero indicating the unrelated tw o random numbers are generated. In the conte xt of the relations, this same analogy can be used to test the dif ference of tw o random numbers generated. T able 3. 1 Bit dif ferences test with k e y v ariations. T est Input k e ys Correlation v alue MAPE Scheme-1 Scheme 2 Scheme-3 Sc heme-1 Scheme-2 Scheme-3 1 ZZZZZZ - ZZZZZY 0.1739823 0.04831424 0 : 0685288 23.9966 3486.022 13.192 2 fti - ftj 0.0220125 0.05469541 0.00900384 612.172 210.2993 46.6942 3 $4LaT1g4 - $4LaT1g3 0 : 011209 0.02911591 0.00971799 64.9543 38.1335 380.158 Ov erall the correlation v alue generated by each scheme is within the range of 0.00 - 2.99. Based on [13], the interv al sho ws the strength of a v ery weak relationship. This condition pro vides information t hat 1 bit k e y input dif ference, can generate dif ferent random numbers on each scheme. Domain Examination of Chaos Lo gistics Function As A K e y Gener ator in Crypto gr aphy (Alz Danny W owor) Evaluation Warning : The document was created with Spire.PDF for Python.
4582 ISSN: 2088-8708 In additi on to the correlation and MAPE analysis, we also tested the distrib ution of random number data using box-plot diagrams.   - 0. 2   0 0. 2 0. 4 0. 6 0. 8 1 1. 2 Figure 6. Box Plot Random Number of Each Scheme Output with V arious Input V ariations Based on Figure 6, each box has almost the same size in which the upper and lo wer whisk er lines v ary slightly , b ut the maximum v alue is al w ays close to one and the minimum is near zero. The distrib ution of data in the chaos range will strengthen the cryptograph y algorithm if used as a k e y , this condition will certainly complicate cryptanalyst to be able to search for infinitely man y numbers although limited. 4. CONCLUSION Each designed scheme is capable of pro viding k e y input fle xibility that can e x ecute domai n logistics function v alues. A 1 bit dif ference in the k e y character af fects e v ery random number generation, so each k e y will generate a dif ferent random number sequence. Under the k e y input conditions of the sam e eight characters, the 1st scheme is better at generating dif ferent initialization v alues than the scheme-2 and schema-3. In addition, the one character reduction of the eight identical characters in the k e y input does not sho w a proportional or re v erse pattern with the initial x 0 v alues and the relati v e error x 0 . The resulting random numbers distrib uted e v enly o v er the chaos range will amplify the algorithm when used as a k e y in cryptograph y . This condition will certainly complicate cryptanalyst to be able to search for infinitely man y numbers although limited. The three schemes ha v e succeeded in fulfilling the nature of the b utterfly ef fect, thus the e xistence of the logistics function in generating chaos numbers can be accommodated based on k e y inputs. Each scheme can be used as a complement to a cryptograph y algorithm to satisfy the dif fusion properties of the Shannon principle. REFERENCES [1] De v ane y , R.L, 1992, A First Course in Chaotic Dynamical Systems: Theory and Experiment , Mass achusetts: Addison- W esle y , Boston. [2] Liw andouw , V . B., & W o w or , A. D., 2015, K ombinasi Algoritma Rubik, CSPRNG Chaos da n S-Box Fungsi Linier dalam Perancang an Kript ografi Block Cipher , Seminar Nasional Sistem Informasi Indonesia , Surabaya: Program Studi Sistem Informasi, ITS. [3] Munir , R., 2011, Enkripsi Selektif Citra Digital deng an Stream Cipher Berbasiskan pada Fungsi Chaotik Logistic Map, Seminar Nasional dan ExpoT eknik Elektro , Uni v ersitas Achmad Dahlan. [4] Munir , R., 2012, Analisis K eamanan Algoritma Enkripsi Citra Digital Menggunakan K ombinasi Dua Chaos Map dan Penerapan T eknik Selektif, Jurnal Ilmiah T eknologi Informasi , V ol. 10, No. 2, Juli: 89-95, Surabaya: ITS. [5] Lestari, D. & Riyanto, M.Z., 2013, Suatu Algoritma Kriptografi Stream Cipher Berdasarkan Fungsi Chaos , Y ogyakarta: MIP A Uni v ersitas Ne geri Y ogyakarta. [6] Gayathri, P . & Syed Umar & Sride vi, G. & Bashw anth, N. & Ro yyuru Srikanth., 2017, Hybrid Cryptograph y for Random-k e y Generation based on ECC Algorithm International Journal of Electrical and Computer Engineering (IJECE) , V ol. 7, No. 3, June: 1293-1298. [7] Krishna, A.R & Chakra v arth y , A.S.N. & Sastry , A.S.C.S, 2017, A Hybrid Cryptographic System for Secured De vice to De vice Communication International Journal of Electrical and Computer Engineering (IJECE) , V ol. 6, No. 6, December: 2962-2970. [8] Chandka v athe, V .M, & Bhaskar , R.S, 2016, Optimized Full P arallelism AES Encryption / Decryption, SSRG Interna- tional Journal of Electronics and Communication Engineering (SSRG - IJECE) , V ol. 3, No. 6, June: 14-16. [9] Chapra, S.C. & Canale, R.P ., 2010, Numerical Methods for Engineers , Sixth Edition, Ne w Y ork: McGra w-Hill. [10] Montgomery , D.C. & Runger , G.C., 2014, Applied Statistics and Probability for Engineers , Sixth Edition, Ne w Jerse y: John W ile y & Sons. [11] Makridaki s, S., Wheel wright, S.C., & McGree, V . E., 1999, Metode dan Aplikasi Peramalan , Jilid 1, Jakarta : Erlangg a. [12] Liw andouw , V .B., & W o w or , A.D., 2015, Desain Algoritma Berbasis K ub us Rubik dalam Perancang an Kriptografi Simetris, Seminar T eknik Informatika dan Sistem Informasi , 9 April 2015, Bandung: FTI Uni v ersitas Kristen Maranatha. [13] Sarw ono, J., 2006, Metode Penelitian K uantitatif dan K ualitatif , Edisi Pertama, Y ogyakarta: Graha Ilmu. IJECE V ol. 8, No. 6, December 2018: 4577 4583 Evaluation Warning : The document was created with Spire.PDF for Python.
IJECE I SSN: 2088-8708 4583 A CKNO WLEDGMENT Thank you to Satya W acana Christian Uni v ersity Research and Community Service Center (BP3M) for the research funding support through the Internal Oblig atory Research scheme in the 2016 fiscal year . BIOGRAPHIES OF A UTHORS Alz Danny W o w or is currently a lecturer at the F aculty of Informa tion T echnology , Satya W acana Christian Uni v ersity in Salatig a, Indonesia. He recei v ed bachelor and master de gree in mathemat- ics and informatics from Satya W acana Christian Uni v ersity , in 2005 and 2011 respecti v ely . His researches are in fields of Primiti v e Crypt ograph y , Symmetric Cryptograph y: Bloc k Cipher and Pseudorandom. V ania Beatrice Liwandouw is a Master of Cyber Security student at F aculty of Science, Radboud Uni v ersity , Nijme gen, The Netherland. She recei v ed her Bachelor de gree in engineering informatics at the F aculty of Information T echnology , Satya W acana Christian Uni v ersity , Salatig a, Indonesia. Her research interests are in the Design and Implem entation of Symmetric Cryptographic Algo- rithms. Domain Examination of Chaos Lo gistics Function As A K e y Gener ator in Crypto gr aphy (Alz Danny W owor) Evaluation Warning : The document was created with Spire.PDF for Python.