Inter national J our nal of Electrical and Computer Engineering (IJECE) V ol. 8, No. 5, October 2018, pp. 3594 3603 ISSN: 2088-8708 3594       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     Steganographic Scheme Based on Message-Co v er matching Y oussef T aouil and El Bachir Ameur Department of Computer Sciences, F aculty of Sciences, Uni v ersity Ibn T of ail, Morocco Article Inf o Article history: Recei v ed No v ember 15, 2017 Re vised May 25, 2018 Accepted July 1, 2018 K eyw ord: Ste g anograph y Data hiding Permutation Least significant bit F aber -Schauder D WT ABSTRA CT Ste g anograph y is one of the techniques that enter into the field of information security , it is the art of dissimulating data into digital files in an imperceptible w ay that does not arise the suspicion. In this paper , a ste g anographic method based on the F aber - Schauder discrete w a v elet transform is proposed. The embedding of the secret data is performed in Least Significant Bit ( LSB ) of the inte ger part of the w a v elet coef ficients. The secret message is decomposed into pairs of bits, then each pair is transformed into another based on a permutation that allo ws to obtain the most matches possible between the message and the LSB of the coef ficients. T o assess the performance of the proposed method, e xperiments were carried out on a lar ge set of images, and a com- parison to prior w orks i s accomplished. Results sho w a good le v el of imperceptibility and a good trade-of f imperceptibility-capacity compared to literature. Copyright c 2018 Institute of Advanced Engineering and Science . All rights r eserved. Corresponding A uthor: Y oussef T aouil LaRIT Laboratory , Department of Computer Sciences, F aculty of Sciences, Ibn T of ail Uni v ersity , 14000 K enitra, Morocco. taouilysf@gmail.com 1. INTR ODUCTION Among the grounds discussed in t h e field of information security is the cryptograph y and data hiding. Cryptograph y protects information by coding its content to become incomprehensible to unauthorized people. But, e v en an incomprehensible message may attract the attention of ea v esdroppers. T o o v ercome this hindrance, ste g anograph y of fers the aspect of ”secrec y” rather than ”incomprehensibilit y”, it is the technique of concealing information through digital media. Its main objecti v e is the secrec y of the information’ s e xistence so that no one aside the authorized recipient may suspect it. In ste g anograph y , v arious media files ha v e been utilized as co v er file such as audio, image, video and plain te xt, b ut among these media, the most popular one to dissimulate secret information is image since it is shared e v eryday on netw orks and also because the human visual system can not detect slight changes done on the image intensity . Generally , there are tw o approaches of ste g anograph y: the spatial domain and the frequenc y domain. In the spatial domain approach, data is hidden directly in the pix els of the co v er image, such as the Least Significant Bit ( LSB ) Substitution” [1], [2]. Ho we v er , this technique is vulnerable to statistical attacks, to protect the hidden message, authors in [3] proposed to encode it using the Hung arian puzzle. There is also the interpolation based techniques [4], [5], [6] where data is hidden in the error between the initial pix els and the interpolated pix els, and the Pix el V alue Dif ferencing ( PVD ) [7], [8], [9] where data is hidden in the dif ference between each neighbouring pix els. In [10], authors proposed a ste g anographic algorithm based on Ant Colon y Optimization (A CO), the A CO algorithm is used to select the comple x re gions of the co v er image, then data is hidden using the LSB substitution in the selected areas. In the frequenc y domain based techniques, data is hidden in the coef ficients of the transform domain, such as Discrete Cosinus T ransform ( DCT ) and Discrete W a v elet T ransform ( D WT ). In [11], a re v ersible data hiding for JPEG images is proposed, the quantization table is modified through di viding some of its elements by an inte ger while multiplying the corresponding quantized DCT coef ficients by the same inte ger in order to create space for the dissimulation. In [12], authors proposed a ste g anographic scheme for JPEG that preserv es J ournal Homepage: http://iaescor e .com/journals/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     DOI:  10.11591/ijece.v8i5.pp3594-3603 Evaluation Warning : The document was created with Spire.PDF for Python.
IJECE ISSN: 2088-8708 3595 the DCT coef ficients histogram in order to resist ste g analysis based attacks. The scheme distinguishes sensiti v e pix els and protects them from the e xtra bit embedding to reduce the distortions in the histogram. In [13], the Inte ger W a v elet T ransform ( IWT ) is applied to each 8 x 8 blocks of the co v er image, then the zero tree method is utilized to select the proper location where data can be embedded. In [14], a ste g anographic scheme based on the Haar D WT is proposed, data is hidden in the first LSB of the D WT coef ficients, the algorithm is generalized on K-LSB with the use of the Optima Pix el Adjustment OP A procedure in [15]. In [16], the edge IWT coef ficients are classified based on their Most Signifi cant bit ( MSB ), the size of data to be hidden in the coef ficient is determined based on the v alue of the coef ficient’ s MSB s. In this paper , we propose a ste g anographic scheme based on the F aber Schauder D WT , this transform allo ws us to hide data in the inte ger part without w orrying about the problem of the floating point (the pix els of the ste go image are guaranteed to be inte gers). Data is hidden in the LSB s of the transform details. The mess age and the coef ficients LSBs are decomposed to pairs of bits m k and z k , and based on the matrix that illustrates the dif ference of distance between m k and z k , we search for the permutation that transforms the message into the binary sequence that has the most possible matches with z k . The selection order of the coef ficients where to dissimulate data is gi v en aleatory by a random k e y . Experiments were performed on a lar ge set of a v ariety of images to assess the perfomance of the proposed w ork, and comparison to prior w orks is accomplished. Results indicate good le v el of imperceptibility and trade-of f capacity-imperceptibility . The remaining of the paper is or g anized as follo ws: Section 2 details the algorithms of decompos ition and reconstruction of the F aber -Schauder D WT . In section 3, the proposed ste g anograph y method is e xplained. In section 4, e xperimental results of the test and comparison are discussed. Section 5 concludes the paper . 2. F ABER-SCHA UDER D WT The F aber -Schauder W a v elet transform is a multi-scale transform, the multi-scale analysis is formu- lated based on the study of compactly supported w a v elet bases, it is the main theory in w a v elets that analyzes in detail a signal in the frequenc y domain. Multi-Scale Analysis of L 2 ( R ) is a sequence of nested v ector spaces ( V j ) j 2 Z ( V j +2 V j +1 V j V j 1 : : : ) . F or all j in Z , V j +1 V j . Let W j +1 be a supplementary of V j +1 in V j : ( V j = V j +1 W j +1 ) , the basis of F aber -Schauder is the basis of W j +1 gi v en by the f amily of functions   j n n 2 Z with:   j n = ' j 2 n +1 , where: ' j n ( t ) = 2 j ' 2 j t n ; and ' ( t ) = 8 < : 1 + t if 1 t 0 1 t if 0 t 1 0 if t = 2 [ 1 ; 1] In tw o dimensions, L 2 ( R 2 ) is approximated by using the tensor product: ~ V j = V j V j = ( V j +1 W j +1 ) ( V j +1 W j +1 ) ; where: ~ V j +1 = V j +1 V j +1 ; and ~ W j +1 = ( V j +1 W j +1 ) + ( W j +1 V j +1 ) + ( W j +1 W j +1 ) Thus, an image C is decomposed into four blocks: A, H, V and D as illustrated in Fig. 1. A corresponds to ~ V j +1 , while H, V , and D correspond respecti v ely to the three subspaces of ~ W j +1 . The decomposition algorithm of F aber -Schauder D WT is gi v en by the follo wing equations: 8 > > > > > > > > < > > > > > > > > : A ( i; j ) = C (2 i; 2 j ) H ( i; j ) = C (2 i + 1 ; 2 j ) C (2 i; 2 j ) + C (2 i + 2 ; 2 j ) 2 V ( i; j ) = C (2 i; 2 j + 1) C (2 i; 2 j ) + C (2 i; 2 j + 2) 2 D ( i; j ) = C (2 i + 1 ; 2 j + 1) 1 X k =0 1 X r =0 C (2 i + 2 k ; 2 j + 2 r ) 4 The reconstruction algorithm or in v erse F aber -Schauder Discrete W a v elet T ransform is gi v en by the Ste gano gr aphic Sc heme Based on Messa g e-Co ver matc hing (Y oussef T aouil) Evaluation Warning : The document was created with Spire.PDF for Python.
3596 ISSN: 2088-8708 Figure 1. One le v el 2D F aber -Schauder D WT of the image Baboon follo wing equations: 8 > > > > > > > > < > > > > > > > > : C (2 i; 2 j ) = A ( i; j ) C (2 i + 1 ; 2 j ) = H ( i; j ) A ( i; j ) + A ( i + 1 ; j ) 2 C (2 i; j + 1) = V ( i; j ) A ( i; j ) + A ( i; j + 1) 2 C (2 i + 1 ; 2 j + 1) = D ( i; j ) 1 X k =0 1 X r =0 A ( i + k ; j + r ) 4 (1) 3. PR OPOSED W ORK 3.1. Embedding Pr ocess After the dissimulation of the secret message, the co v er image is modified, the principal objecti v e of ste g anograph y is to minimize this modification so that the hiding does not arise the suspicion of ea v esdroppers. The proposed method is based on F aber -Schauder D WT . The block A represents the approximation of the image co v er , it contains the lo w frequencies where the human e ye is sensiti v e to slightest modifications. A should remain unchanged. Therefore, data is hidden in the three remaining blocks H, V , and D . Let m be the binary sequence of the secret message m = f m 1 ; : : : ; m L g m k 2 f 0 ; 1 g , and let Z be the set of the LSB of the inte ger part of the coef ficients of the blocks H , V and D . W e di vide m and Z into pairs m = S m k and Z = S z k , where m k = f m 2 k 1 ; m 2 k g and z k = f z 2 k 1 ; z 2 k g . 8 k m k and z k are in the set E = ff 0 ; 0 g ; f 0 ; 1 g ; f 1 ; 0 g ; f 1 ; 1 gg . When m k is hidden into z k there are three possibiliti es: the y are identical m k = z k , conjug ate m k + z k = f 1 ; 1 g or the y ha v e one bit dif ferent. T o visualize all these possibilities, we introduce the matrix G whose elements denote the number of times each pair m k from E encounters a pair z k from E . G is a 4 x 4 matrix, because car d ( E ) = 4 , its elements are inte ger between 0 and L= 2 , G 2 M 4 ; 4 ( f 0 ; : : : ; L= 2 g ) . The first column is associated to f 0 ; 0 g , the second column to f 0 ; 1 g , the third column to f 1 ; 0 g and the last column to f 1 ; 1 g . The same thing goes for the ro ws. If m k encounters z k , then the element G i;j from the i ro w and j column is incremented, where the relation between the pairs, ro ws and columns is gi v en by the follo wing function f which is a bijection that associates each pair to its decimal v alue plus 1: IJECE V ol. 8, No. 5, October 2018: 3594 3603 Evaluation Warning : The document was created with Spire.PDF for Python.
IJECE ISSN: 2088-8708 3597 j = f ( m 2 k 1 ; m 2 k ) = 2 m 2 k 1 + m 2 k + 1 i = f ( z 2 k 1 ; z 2 k ) = 2 z 2 k 1 + z 2 k + 1 (2) In each column, the diagonal element sho w ho w much times m k and z k are identical, the element of the 2 nd diagonal denotes the number of ti mes when m k and z k are opposite or conjug ate. The remaining tw o elements denote ho w much times m k and z k ha v e on bit dif ferent. Example: 26 denotes ho w man y times f 0 ; 1 g of the message encounters f 1 ; 0 g in t he the coef ficients LSB s. G = 0 B B B B @ f 0 ; 0 g f 0 ; 1 g f 1 ; 0 g f 1 ; 1 g f 0 ; 0 g 64 36 87 51 f 0 ; 1 g 38 57 72 93 f 1 ; 0 g 19 26 18 17 f 1 ; 1 g 29 16 27 21 1 C C C C A The error generated by the dissimulation is e xpressed by the follo wing e xpression: M S E = 1 M N M 1 X i =0 N 1 X j =0 ( S ( i; j ) C ( i; j )) 2 Let H 0 ( i; j ) be the coef ficient produced after hiding data in H ( i; j ) , and h ( i; j ) = H 0 ( i; j ) H ( i; j ) the dif ference coming from this dissimulation. W e define v ( i; j ) and d ( i; j ) the same w ay . Therefore, using the reconstructions equations (1), the MSE becomes: M S E = 1 M N M = 2 1 X i =0 N = 2 1 X j =0 h ( i; j ) 2 + v ( i; j ) 2 + d ( i; j ) 2 The diagonal elements of the matrix G corresponds to when data is hidden with zero changes, the 2nd diagonal elements corresponds to when 2 changes are needed, and the rest corres ponds to when one bit is changed to hide 2 bits, as described in the follo wing matrix W G . W G = 0 B B @ 0 1 1 2 1 0 2 1 1 2 0 1 2 1 1 0 1 C C A Hence, we can reformulate the MSE based on the matrix G as follo ws: M S E = 1 M N 4 X i =1 4 X j =1 W G ( i; j ) G ( i; j ) which we can reformulate as follo ws: M S E = 1 M N 0 @ 4 X i =1 4 X j =1 G i;j + 4 X i =1 G 5 i;i tr ( G ) 1 A where tr ( G ) is the trace of the matrix G : tr ( G ) = 4 X i =1 G i;i Since 4 X i =1 4 X j =1 G i;j is unchanged for all permutations, then we define the function # which associates the remaining tw o terms to the permutation: # : S 4 ! Z p 7 ! 4 X i =1 G 5 i;i tr ( G ) Ste gano gr aphic Sc heme Based on Messa g e-Co ver matc hing (Y oussef T aouil) Evaluation Warning : The document was created with Spire.PDF for Python.
3598 ISSN: 2088-8708 T o minimize the MSE , we calculate # ( p ) for all possible p in S 4 (24 permutations). Then, we search for the permutation p corresponding to the lo west v alue of # ( p ) . p = min p 2 S 4 ( # ( p )) . The equation p ( j ) = j 0 signifies that the column j is permuted into j 0 , which means that the pair m k associated to j by the function f introduced in (2) is consequently changed to the pair associated to j 0 . F or e xample, if p (3) = 1 , then by using the function f , f 1 (3) is changed int o f 1 (1) i.e. each pair f 1 ; 0 g in the secret message is changed into f 0 ; 0 g . Hence, we obtain t he transformation of the secret message m 0 that allo ws us to reach the lo west MSE calculated. m 0 is gi v en by: m 0 = L= 2 [ k =1 f 1 o p o f ( m k ) (3) Example: W e consider the message H E L L O ”, the binary sequence of this message is m = 0100100001100101011011000110110001101111 . W e decompose m into pairs: m = 01 j 00 j 10 j 00 j 01 j 10 j 01 j 01 j 01 j 10 j 11 j 00 j 01 j 10 j 11 j 00 j 01 j 10 j 11 j 11 . Suppose that the LSB s of the coef ficients are : Z = 00 j 11 j 00 j 01 j 11 j 01 j 10 j 00 j 10 j 10 j 10 j 11 j 11 j 10 j 00 j 10 j 10 j 10 j 00 j 10 : W e construct the matrix G : G = 0 B B @ 0 2 1 2 1 0 1 0 1 3 3 2 2 2 0 0 1 C C A The error no w is 25 , which means that there is 25 among the 40 message bits that are going to be dissimulated into their opposite bits of the coef ficients. No w , we calculate the errors of the 24 permutations and we choose the permutation p associated to the lo west error . p and its associated G are gi v en by p = 1 2 3 4 4 3 2 1 ; G = 0 B B @ 2 1 2 0 0 1 0 1 2 3 3 1 0 0 0 2 1 C C A The error becomes 15. Hence, we construct the ne w binary sequence m 0 based on the equation (3) as follo ws: f 0 ; 0 g ! f 1 ; 1 g ; f 0 ; 1 g ! f 1 ; 0 g ; f 1 ; 0 g ! f 0 ; 1 g ; f 1 ; 1 g ! f 1 ; 1 g 3.2. Extraction pr ocess In the e xtraction, we retrie v e the message m 0 from the LSB of the coef ficients’ inte ger part. T o be able to obtain the actual mes sage m , the permutation p is needed. Thus, in the dissimulation phase, we hide an identifier in the first coef ficients. p (1) , p (2) , p (3) and p (4) are hidden int the first eight coef ficients. After the e xtraction of m 0 , we use the p ( i ) to retrie v e the message m as follo ws: m = L= 2 [ k =1 f 1 o ( p ) 1 o f ( m 0 k ) where m 0 k = f m 0 2 k ; m 0 2 k +1 g IJECE V ol. 8, No. 5, October 2018: 3594 3603 Evaluation Warning : The document was created with Spire.PDF for Python.
IJECE ISSN: 2088-8708 3599 Embedding algorithm Read the co v er image as tw o dimensional file. Perform the F aber -Schauder D WT . Construct the matrix G , find the perm u t ation p and hide p (1) , p (2) , p (3) and p (4) in the first eight coef ficients. T ransform the binary sequence of the message m into m 0 using p and f and hide it in the coef ficients starting from the se v enteenth one. Apply the in v erse F aber -Schauder discrete w a v elet transform to obtain the ste go image. Extraction algorithm Read the ste go image as tw o dimensional file. Apply the F aber -Schauder D WT to the ste go image. Extract the permutation p from the first eight coef ficients and the identifier of the the k e y from the second eight coef ficients. Extract the binary sequence m 0 from the coef ficients, and reconstruct m using the function f and permu- tation p . Re group the binary sequence m by blocks of 8 bits to obtain the hidden message. 4. EXPERIMENT AL RESUL TS AND DISCUSSION Experiments were accomplished to assess the performance of the proposed method using a v ariety of 512x512 grayscale images of the SIPI database, containing some images which are frequently utilized in tests, lik e ”Baboon”, ”Peppers”, ”Lena” and ”Elaine” (see Fig. 2). Baboon Elaine Barbara Lak e Peppers Boat Lena F16 Figure 2. Some of the images used in the e xperiment The proposed w ork is compared with the methods de v eloped by Amin [13], Miri [16] and Al-Dmour [17]. The test of the proposed w ork and the comparison are based on the follo wing metrics [18]: Ste gano gr aphic Sc heme Based on Messa g e-Co ver matc hing (Y oussef T aouil) Evaluation Warning : The document was created with Spire.PDF for Python.
3600 ISSN: 2088-8708 P S N R = 10 Log 255 2 M S E ; N AE = M 1 X i =0 N 1 X j =0 j S ( i; j ) C ( i; j ) j M 1 X i =0 N X j =1 C ( i; j ) I F = 1 M 1 X i =0 N 1 X j =0 ( S ( i; j ) C ( i; j )) 2 M 1 X i =0 N 1 X j =0 C ( i; j ) 2 ; N C C = M X i =1 N X j =1 ( C ( i; j ) C )( S ( i; j ) S ) v u u t M X i =1 N X j =1 ( C ( i; j ) C ) 2 v u u t M X i =1 N X j =1 ( S ( i; j ) S ) 2 The PSNR is the Peak Signal to Noise Ratio, it is calculated using the MSE . The more PSNR increases, the more the ste g anographic scheme is imperceptible. The N AE is the Normal Absolute Error , it measures the absolute v alue of the error between the co v er and ste go images. Small v alues of N AE (close to 0) are a sign of good imperceptibility . IF is the Image Fidelity , the quantity 1 I F measures the ratio of the ener gy of the error between the co v er and ste go images to the ener gy of the co v er image. Ob viously , good imperceptibility requires that 1 I F is v ery close to 0, which means that IF has to be v ery close to 1. The Normalized Correlation Coef ficient NCC is a scalar product of the normalized v ectors v C and v S while v C is the co v er image minus its mean v alue C and v S is the ste go image minus its mean v alue S , so it tak es v alues between 1 and 1 . The closer NCC is to 1 , the more similar are the images. If it is close to 0 , the images are uncorrelated, and if it is close to 1 , the images are said opposite. 4.1. T est of the pr oposed method T o test the proposed method, we used a set of 100 images with dif ferent modalities, do wnloaded from the SIPI image database. T able 1. Imperceptibility for the proposed method Metrics PSNR N AE IF NCC PSNR N AE IF NCC Data 3000 bytes 6000 bytes Min 61.55 2.01e-4 0.999973 0.999654 58.53 4.01e-4 0.999964 0.999371 Max 62.31 1.38e-3 0.999999 0.999997 59.25 2.77e-3 0.999998 0.999994 Mean 61.71 3.69e-4 0.999997 0.999948 58.68 7.42e-4 0.999994 0.999893 Data 9000 bytes 12000 by t es Min 56.76 6.02e-4 0.999921 0.999073 55.52 8.05e-4 0.999893 0.998526 Max 57.53 4.14e-3 0.999997 0.999987 56.25 5.51e-3 0.999996 0.999982 Mean 56.92 1.11e-3 0.999991 0.999842 55.67 1.48e-3 0.999988 0.999778 Data 18000 bytes 24000 bytes Min 53.75 1.21e-3 0.999841 0.998147 52.51 1.61e-3 0.999787 0.997565 Max 54.49 8.29e-3 0.999994 0.999972 53.28 1.11e-2 0.999992 0.999962 Mean 53.91 2.22e-3 0.999982 0.999671 52.65 2.96e-3 0.999976 0.999554 T able 1 presents the results of the imperceptibility test for the proposed method, based on the m etrics PSNR , N AE , IF and NCC . In this simulation, we dissimulated in the 100 test images a te xt of 3, 6, 9, 12, 18 and 24 Kilo Bytes. The table gi v es the minimum, maximum and mean v alues. A ste g anograph y process is imperceptible when PSNR is be yond 36 dB. The PSNR v alues indicate a high le v el of imperceptibility , N AE v alues are v ery small , N AE < 10 2 , and IF is practically 1, j 1 I F j < 10 4 . NCC v alues are v ery close to 1, j 1 N C C j < 10 3 , which pro v es that the co v er and ste go images are practically ident ical. Figure 3 e xhibits the e v olution of the PSNR for all the test images as the size of the hidden data increases. The PSNR diminishes, because when we hide lar ger data, the error becomes important. Ho we v er , the drop of the imperceptibility becomes slo wer , when data size increas es from 12 Kilo to 18 Kilo and from 18 Kilo to 24 Kilo, the mean PSNR decreases by 1 : 76 dB and 1 : 26 dB respecti v ely . IJECE V ol. 8, No. 5, October 2018: 3594 3603 Evaluation Warning : The document was created with Spire.PDF for Python.
IJECE ISSN: 2088-8708 3601 Figure 3. Capacity-Imperceptibility 4.2. Comparison to literatur e The proposed w ork is compared to the methods de v eloped by Amin [13], Miri [16] and Al-Dmour [17]. The tests of the comparison respects the same conditions (images, size of hidden data) utilized i n these w orks. T able 2 sho ws the results of comparison of PSNR to Amin’ s w ork for the four images used in his w ork, and table 3 compares the capaci ty of hiding. The proposed w ork pro vides a lar ger capacity 3 4 M N 8 bits, about 2 : 3 times the one of Amin, the subtra cted 8 bits are reserv ed to hide the permutation p . In the algorithm he proposed, Amin does not hide data in all the w a v elet coef ficients, he selects the location where to hide data via the zero tree method, hence the capacity is diminished. On another hand, e v en concerning the imperceptibility , the proposed w ork still has better results, for 100 , 500 and 1 K bytes, the dif ference is approximati v ely 1 dB . But, when we hide 5 K , 10 K and 15 K bytes, the dif ference becomes 3 dB . T able 2. Comparison of PSNR to Amin [13] Image Method 100 500 1000 5000 10000 15000 Barbara Amin 73.98 66.61 63.64 65.55 53.64 52.02 Proposed 76.57 69.46 66.38 59.37 56.35 54.59 Peppers Amin 74.12 66.61 63.78 56.54 53.58 51.89 Proposed 76.61 69.45 66.42 59.34 56.34 54.57 Baboon Amin 75.62 68.18 62.89 56.06 53.32 51.75 Proposed 76.59 69.40 66.38 59.35 56.32 54.56 Lena Amin 73.58 66.07 63.01 56.18 53.38 51.65 Proposed 76.57 69.42 66.41 59.37 56.37 54.59 T able 4 sho ws the results of the comparison of the PSNR to Miri [16] and Al-Dmour [17], we respected the size of hidden data used in [16]. The proposed w ork has higher v alues. F or Miri, the dif ference is around 3 : 6 dB. In f act, Miri may hide data in more than one bit on a w a v elet coef ficient depending on the weight (position) of the most significant bit, the greater is the position, the more bits of the coef ficients are used to embed data, in this case, the error generated from the dissimulation increases, which af fected his PSNR v alues. As for Al-Dmour [17], the dif ference starts with 3 dB , authors hide data in the edge coef ficients and use the XOR cording in order to minimize the error of the dissimulation. Ho we v er , as the size of data increased, more Ste gano gr aphic Sc heme Based on Messa g e-Co ver matc hing (Y oussef T aouil) Evaluation Warning : The document was created with Spire.PDF for Python.
3602 ISSN: 2088-8708 T able 3. Comparison of the hiding capacity to Amin [13] Image Size Amin [13] Proposed Lena 128x128 5145 11891 Lena 256x256 20622 48371 Lena 512x512 82578 195059 Peppers 128x128 5223 11891 Peppers 256x256 20694 48371 Peppers 512x512 83846 195059 T able 4. Comparison of PSNR to Miri [16] and Al-Dmour [17]. Data size Al-Dmour Miri Proposed 6300 bits 64.76 63.80 67.44 12800 bits 61.50 60.66 64.32 28800 bits 56.91 56.79 60.78 51200 bits 52.62 54.78 58.28 67700 bits 50.28 53.68 57.06 bits of the edge coef ficients are used to dissimulate data (and depending of the co v er image comple xity , more bits of the coef ficient may be used), which decreases significantly the PSNR . Hence, the dif ference enlar ged to about 7 dB since in our case, we use only one bit in each coef ficient, and the optimal permutation p transforms the message into the best match for the co v er image. 5. CONCLUSION In this paper , a ste g anographic method based on F aber -Sc hauder D WT is proposed. Data is di vided into pairs of 2 bits, the same is done to the LSB of the details in the transform domain. W e establish a matrix that c alculates the number of times where data and the coef ficients are similar or opposite, and based on this matrix we find the permutation that transforms the message into the binary sequence that pro vides the most match possible to the coef ficients LSB s. Results sho wed good trade-of f between capacity and imperceptibility , and higher v alues in both of them compared to e xisting methods. In our future w orks, we will study more ho w to minimize the error generated by the dissimulation and we will strengthen the security through the analysis of the hiding’ s ef fect on the histogram. REFERENCES [1] C. K. Chan and L. M. Cheng, ”Hiding data in images by simple LSB substitution, P attern Recognition, v ol. 37, pp. 469-474, 2004. [2] C. C. Chang, J. Y . Hsiao and C. S. Chan, ”Finding optimal least-significant-bit substitution in image hiding by dynamic programming strate gy , P attern Recognition, v ol.36, pp. 1583-95, 2003. [3] E. Alrashed, S. S. Alroomi, ”Hung arian-Puzzled T e xt with Dynamic Quadratic Embedding Ste g anogra- ph y , International Journal of Electrical and Computer Engineering (IJECE), v ol. 7, pp. 799-809, 2017. [4] A. Benhfid, E. B. Ameur and Y . T aouil, ”High capacity data hiding methods based on spline inter - polation, 5th International Conference on Multimedia Computing and Systems (ICMCS) , 2016, doi: 10.1109/ICMCS.2016.7905641. [5] M. T ang, S. Zeng, X. Chen, J. Hu and Y . Du, ”An adapti v e image ste g anograph y usi ng AMBTC com- pression and interpolation technique, International Journal for Light and Electron Optics , v ol. 127, pp. 471-477, 2016. [6] J. Hu and T . Li, ”Re v ersible ste g anograph y using e xtended image interpolation technique, Computers & Electrical Engineering , v ol. 46, pp. 447-455, 2015. [7] M. B. Jahromi and K. F aez, ”An Adapti v e Ste g anograph y Scheme Based on V isual Quality and Embedding Capacity Impro v ement”, International Journal of Electrical and Computer Engineering , v ol. 4, pp. 573-584, Aug 2014. [8] M. Hussain, A. W . Abdul W ahab, A. T . S. Ho, N. Ja v ed and K.H. Jung, ”A data hiding scheme using parity-bit pix el v alue dif ferencing and impro v ed rightmost digit replacement, Signal Processing: Image IJECE V ol. 8, No. 5, October 2018: 3594 3603 Evaluation Warning : The document was created with Spire.PDF for Python.
IJECE ISSN: 2088-8708 3603 Communication , v ol. 50, pp. 44-57, 2017. [9] M. S. Arya, M. Rani and C. S. Bedi, ”Impro v ed Capacity Image Ste g anograph y Algorithm using 16Pix el Dif ferencing with n-bit LSB Substitution for RGB Images, International Journal of Electrical and Com- puter Engineering ”, v ol. 6, pp. 2735-2741, Dec 2016. [10] S. Khan, T . Bianchi, ”Ant Colon y Optimization (A CO) based Data Hiding in Image Comple x Re gion, International Journal of Electrical and Computer Engineering (IJECE), V ol. 8, pp. 379-389, Feb 2018. [11] K. W ang, Z. M. Lub and Y . J. Hu, ”A high capacity lossless data hiding scheme for JPEG images, Journal of Systems and Softw are , v ol. 86, pp. 1965-1975, 2013. [12] K. Qazanf ari and R. Saf abakhsh, ”A ne w ste g anograph y method which preserv es histogram: Generaliza- tion of LSB++, Information Sciences , v ol. 277, pp. 90-101, 2014. [13] S. A Se yyedi and N. Iv ano v , ”A No v el Secure Ste g anographic Method Based on Zero T ree Method, International Journal of Adv anced Studies in Computer Science & Engineering , v ol. 3, no. 3, 2014. [14] Y . T aouil, E. B. Ameur , M. T . Belghiti, ”Ne w Image Ste g anograph y Method Based on Haar Discrete W a v elet T ransform”. EMEN A-TSSL, Adv ances in Intelligent Systems and Computing , v ol. 520, pp. 287- 297, Oct 2016. [15] Y . T aouil, E. B. Ameur , A. Benhfid, R. Harba and R. Jennane, ”A Data Hiding Scheme Based on the Haar Discrete W a v el et T ransform and the K-LSB, International Journal of Imaging and Roboti cs , v ol. 17, pp. 41-53, 2017. [16] A. Miri and K. F aez, ”An image ste g anograph y method based on inte ger w a v elet transform, Multimed T ools Appl , 2017, doi:10.1007/s11042-017-4935-z [17] H. Al-Dmour and A. Al-Ani, ”A ste g anograph y embedding method based on edge identification and XOR coding, Expert Syst Appl , v ol. 46, pp. 293306, 2016. [18] M. S. Subhedar and V . H. Mankar , ”Image ste g anograph y using redundant discrete w a v elet transform and QR f actorization, Computers and Electrical Engineering , v ol. 54, pp. 406-422, 2016. BIOGRAPHIES OF A UTHORS Y oussef T aouil is a PhD Student at the f aculty of sciences in Ibn T of ail Uni v ersity , he obtained the Engineering diploma in electronics and embedded systems from the national school of applied sciences at the sam e Uni v ersity (2014). His researches are focused on ste g anograph y and data hiding. El Bachir Ameur is a full Professor of computer sciences at the Uni v ersity of IbnT of ail, F aculty of science, K enitra (Morocco), where he is af filiated to t he LaRIT Laboratory . In 2002 he recei v ed the Ph. D. de gree in numerical analysis and computer sciences from the Uni v ersity of Mohamed I Oujda (Morocco). His Ph. D. concerned a pproximation and reconstruction of 2D/3D data by spline and w a v elet functions. His research interests concerns approximation and reconstruction of 2D/3D surf aces by spline and w a v elets, signal and image processing, w atermarking and ste g anograph y . Ste gano gr aphic Sc heme Based on Messa g e-Co ver matc hing (Y oussef T aouil) Evaluation Warning : The document was created with Spire.PDF for Python.