Madhumita Sengupta

Authentication/Secret Message Transformation through Wavelet Transform Based Subband Image Coding (WTSIC)

In this paper a DWT based frequency domain steganographic technique, termed as WTSIC has been proposed where the cover PPM image transform into the time domain through DWT, resulting four sub-image components as ‘Low resolution’, ‘Horizontal orientation’, ‘Vertical orientation’ and ‘Diagonal orientation’. Secret message/image bits stream in varying positions are embedded in all three components and the experimental results against statistical and visual attack has been computed and compared with the existing steganographic algorithm like IAFDDFTT, [1] in terms of Mean Square Error (MSE), Peak Signal to Noise Ratio (PSNR), Standard Deviation (SD) Analysis and Image fidelity (IF) Analysis, which shows better performances in WTSIC.

Steganographic Technique Based on Minimum Deviation of Fidelity (STMDF)

In this paper a minimum deviation of fidelity based data embedding technique (STMDF) has been proposed where two bits per byte have been replaced by choosing the position randomly between LSB and up to fourth bit towards MSB. This technique also optimized the intensity value of pixel after embedding by comparing it with original pixel value. STMDF technique has been compared with existing Wu-Tsais Method [1] and H.C. Wu Method [2] techniques, where proposed technique shows better performance in terms of PSNR and fidelity of the stego images.

Self authentication of color images through discrete cosine transformation (SADCT)

In this paper a DCT based steganographic technique in frequency domain, termed as SADCT has been proposed for authentication of color images. The cover image transformed into the time domain using 8×8 mask in row major order using DCT resulting its corresponding frequency components. Highest frequency values are fetched from red and green components of transformed RGB matrix as watermark. Using a secret key and a hash function watermarks are embedded into blue components of the cover image in spatial domain. Experimental results are computed and compared with the existing steganographic techniques like IAFDDFTT[1] and SAWT [9] in terms of Mean Square Error (MSE), Peak Signal to Noise Ratio (PSNR), Standard Deviation (SD) and Image Fidelity (IF) which show better performances in SADCT.

Image Authentication Using Hough Transform Generated Self Signature in DCT Based Frequency Domain (IAHTSSDCT)

In this paper a DCT based steganographic technique in frequency domain, termed as IAHTSSDCT has been proposed for authentication of gray scale images. The cover image passes through Hough transformation based on hash function to generate unique signature treated as secret information. As the first step of embedding the cover image transformed into time domain using 2x2 masks in row major order using DCT resulting its corresponding frequency components. Using a secret key and hash function the secret signature/information is embedded into selective AC coefficients. To generate stegoimage those frequency coefficients then passes through inverse DCT. Extraction is also done through same procedure. Experimental results are computed and compared with the existing steganographic techniques like SAWT [1] and YulinWang [3] in terms of Mean Square Error (MSE), Peak Signal to Noise Ratio (PSNR) and Image Fidelity (IF) which show better performances in IAHTSSDCT.

Authentication in Higher Region of Convergence of Z Transform Domain (AHRocZ)

In this paper a novel technique for authentication has been proposed in composite real and imaginary components of Z transform domain in higher region of convergence \( (r = 2) \). Three bits from authenticating image are embedded into real as well as imaginary components of second, third and fourth transform domain coefficients keeping the low frequency component as it is and is used for adjustment. The proposed method obtain a good security in terms of robustness and sensitivity of Z transform in higher magnitude. A comparison has been made with existing methods such as AINCDCT (Authentication of images through non convoluted DCT, IEEE, pp. 1–4, 2011 [3]), Luo’s Method (Inf Sci 181:308–328, 2011 [4]), SCDFT (IEEE Trans Inf Forensics Secur 3(1):16–28, 2008 [5]) which shows better performance and visual quality.

Image Authentication in Frequency Domain through G-Let Dihedral Group (IAFD-D3)

In this paper a G-Let based authentication technique has been proposed to authenticate digital documents by embedding a secret image/message inside the cover image in frequency domain. Cover image is transformed into G-Let domain to generate 2n number of G-Lets out of which selected G-Let(s) are embedded with secret message for the purpose of authentication or copyright protection. The special feature of IAFD-D3 is the use of Dihedral Group with ‘n’ equals to three. Thus total six G-Lets are generated out of which only single G-Let is used as a locker to lock the secret. Experimental results are computed and compared with the existing authentication techniques like GASMT, Li’s Method, STMDF, Region-Based based on Mean Square Error (MSE), Peak Signal to Noise Ratio (PSNR), Image Fidelity (IF), Universal Quality Image (UQI) and Structural Similarity Index Measurement (SSIM) shows better performance in IAFD-D3, in terms of low computational complexity and better image fidelity.

Color Image Authentication through Visible Patterns (CAV)

In this paper a copyright protection technique based on visual patterns (CAV) has been proposed for color image. This technique manipulates bits of color image to hide the hash of secret without embedding secret directly. Three layers of random noise, generated by R, G and B through hash function, when fall upon a base noise can able to generate imprint of secret in the form of visual patterns. Same process on receiver end authenticates the originality of image and protects ownership. CAV also optimized the intensity value of pixel after embedding by comparing it with original pixel value. Proposed CAV technique has been compared with existing Wu-Tsai’s Method, H.C. Wu Method, SAWT and STMDF techniques, where proposed technique shows better performance in terms of MSE, PSNR and fidelity of the stego images.

G-Let Based Authentication/Secret Message Transmission (GASMT)

In this paper a G-Let based steganographic technique, termed as GASMT has been proposed for authentication of gray scale images. The cover image transformed into one to many G-Lets based on group theory. n number of G-Lets are embedded with secret message/image for authentication. Using a secret key and hash function watermarks/secret are embedded into few G-Let components of the cover image followed by adjustment/tuning of embedded G-Lets components to minimize the noise integration. At the receiving end embedded G-Lets are used for authentication. Experimental results are computed and compared with the existing authentication techniques like Lis method, SCDFT, Region-Based method based on Mean Square Error (MSE), Peak Signal to Noise Ratio (PSNR), Image Fidelity (IF), Universal Quality Image (UQI) and Structural Similarity Index Measurement (SSIM) which shows better performance in GASMT, in terms of low computational complexity and better fidelity.

KSOFM Network Based Neural Key Generation for Wireless Communication

In this paper a single layer perceptron (KSOFM Network) based neural key generation for encryption/decryption for wireless communication has been proposed. Identical KSOFM network has been used in both sender and receiver side and the final output weight has been used as a secret key for encryption and decryption. The final output matrix of the KSOFM network is taken and the minimum value neuron in the matrix is considered as the secret key. Depending upon the input and output neuron, different keys has been generated for each session which helps to form secret session key. In sender side the plain text is encrypted with the secret key to form the cipher text done by the EX-OR operation between the secret key and the plain text. Receiver will use the same secret key to decrypt the cipher text to plane text. The secret key is not sent via any medium so it minimizes the man-in-the-middle attack. Moreover various tests are performed in terms of chi-square test, which shows comparable results with the said proposed system.

Adaptive Partial Image Encryption Technique Based on Chaotic Map

In this paper an adaptive partial image encryption technique has been proposed based on Chaotic Map generation. Gray scale image is decomposed into its corresponding binary eight biplanes. Among the biplanes, the significant biplanes are determined for scrambling. All the biplanes are encrypted and scrambled by applying Pseudo Random Binary Number Generator using the recurrence relation of skew tent map based on Chaos. The significant biplanes are encrypted through triangularization technique. All scrambled biplanes along with encrypted significant biplanes are recombined to generate cipher image. In order to evaluate performance, the proposed algorithm is measured through a series of tests has been applied on to measure the security and effectiveness of the algorithm. These are visual test through histogram analysis, measures of central tendency and dispersion, correlation-coefficient analysis, key sensitivity test, key space analysis, information entropy test, which show that the proposed technique outperforms compared to the existing techniques.