High Capacity Signature Hiding Technique in Higher Depth of LSB Layer
International Journal of Multimedia and Ubiquitous Engineering
Today Signature is very popular authentication information. Here we try to hide this confidential information by Steganography. This security technique prevents discovery of the very existence of communication through digital media. In our proposed work the LSB replacement technique of Steganography is used. Here we able to increase imperceptibility as well as capacity of stego image by considering higher LSB layer for hiding the target data and replacing multiple bits. [So we see that six
... e see that six pixel of target image are inserted into a single pixel of cover image.] Step 9: Send the stego image to the receiver. Step 10: End. Algorithm for length storing Function st_len(cover image, t_row, t_col) [t_row and t_col be the row and column size of target image,respectively.] Step 1: Count the number of digit in t_row and t_col value. Step 2: Convert these two numbers into 4 bit binary and store these in r_bin and c_bin. Step 3: Replace 1 st and 2 nd LSB of Red and Green component of first pixel of first row of the cover image with 3 rd -4 th and 1 st -2 nd bits of r_bin. Step 4: Replace 1 st and 2 nd LSB of Red and Green component of first pixel of first row of the cover image with 3 rd -4 th and 1 st -2 nd bits of c_bin. Step 5: Cut the digit of t_row value. Step 6: Convert each digit into 4 bit binary. Step 7: Replace 1 st and 2 nd LSB of Red and Green component of each pixel of first row of the cover image with 3rd -4 th and 1st -2 nd bits from LSB of each 4 bit binary. Step 8: Restore the bits of Red, Green component of modified pixel in the cover image. Step 9: Apply Step 5, 6, 7 and 8 for column size t_col also. Step 10: end Algorithm for bit adjustment Function adjust (cover image, t_row, t_col) [t_row and t_col be the row and column size of target image,respectively.] Step 1: Start Step 2: Convert the R, G, B values of the selected pixel of the cover image to its corresponding binary value. Step 3: For each of the R, G, B components of the selected pixel (P) of the cover image repeat the following steps Step 4: Replace the 5 th bit (from the LSB) with the pixel value of the Target image (say S(i), where i =1,2,.......S). Step 5: if the change in the 5 th bit is from 0 to 1 follow the following steps Step 5.1: let the a i = 5 th bit, if a i-1 =1 and a i+1 =1 then set a i-1 , a i-2 ,.... a 0 = 0 Step 5.2: else if a i-1 =1 and a i+1 =0 then set a i-1 , a i-2 ,.... a 0 = 0 Step 5.3: else if a i-1 =0 then set a i-1 , a i-2 ,.... a 0 = 1 Step 6: if the change in the 5 th bit is from 1 to 0 follow the following step Step 6.1: let the a i = 5 th bit, if a i-1 =0 and a i+1 =0 then set a i-1 , a i-2 ,.... a 0 = 1 Step 6.2: else if a i-1 =0 and a i+1 =1 then set a i-1 , a i-2 ,.... a 0 = 1 Step 6.3: else if a i-1 =1 then set a i-1 , a i-2 ,.... a 0 = 0 Step 6.3.1: if a i+1 =0 then set a i+1 = 1 Step 6.4: else j= i+1, while ( a j ! = 0 ) set a j = 0 Step 6.4.1: increment j Step 6.4.2: set a j = 1 Step 7: Set a(0), i.e 1 st bit from the LSB = S(i+1), i.e the next pixel of target image. Step 8: End Decoding Algorithm Step 1: Take the stego image as input at the receiver side. Step 2: The row and column size first extracted from first row of the stego image. Step 3: Iterate the decoding algorithm according to the size of the target image. Step 3.1: Take a pixel of cover image. Step 3.2: Pick 5 th and 1 st LSB of R plane of target image. Step 3.3: Pick 5 th and 1 st LSB of G plane of target image. Step 3.4: Pick 5 th and 1 st LSB of B plane of target image. Step 4: Restore them for forming the target image. Step 5: End Result Signature is very secure as well as important information for authentication. We should transmit this instruction secretly and for hide its existence during transmission here in our proposed technique we embed signature within a RGB cover image. After applying our proposed method we can hide this and the results are shown Figure 1 and Figure 2 .