Implementation of Steganalysis Technique Using Chi Square Attack Method on Android-Based JPEG Stego Image Format

Steganografi merupakan seni dalam menulis pesan rahasia untuk menyembunyikan informasi dengan cara meniyisipkan pesan pada suatu citra, sehingga tidak menutup kemungkinan steganografi dimanfaatkan untuk tujuan kriminal atau penyisipan file berbau pornografi. Sedangkan steganalysis merupakan teknik untuk mendeteksi keberadaan pesan yang tersembunyi pada cover image. Pada penelitian ini menggunakan teknik steganalysis dengan metode chi-square attack untuk mendeteksi keberadaan pesan secara statistik. Tujuan dari penelitian ini adalah mengembangkan teknik steganalysis dengan menggunakan metode chi-square attack untuk mendeteksi stego-image berformat JPEG dan mengetahui hasil analisa dari metode chi-square attack yang diterapkan pada aplikasi Android Studio. Metode yang digunakan pada penelitian ini adalah metode waterfall, yang terdiri dari tahap analisis kebutuhan, tahap desain, tahap implementasi, tahap verifikasi dan tahap pemeliharaan. Hasil teknik steganalysis dengan metode chi square attack, yaitu uji coba pertama menghasilkan nilai selisih pada ukuran kapasitas file sebesar 1 hingga 12 persen, yang membuktikan teknik dengan metode chi square attack dapat mengestimasi atau memperkirakan panjang pesan yang disisipi dalam suatu objek gambar. Pada tahap uji gambar acak diperoleh hasil chi square 0,60021 yang berarti 60 persen peluang adanya pesan yang disisipkan dalam gambar dan sebesar 0,09999 ataupun sebesar 0,10001 yang berarti 9 persen atau terdapat 10 persen peluang adanya pesan yang disisipkan atau dapat diartikan gambar tersebut tidak disisipi suatu pesan atau data.

New Steganography System Based on Huffman Coding and Fibonacci Decomposition

Hiding secret information in the image is a challenging and painstaking task in computer security and steganography system. Certainly, the absolute intricacy of attacks to security system makes it more attractive.in this research on steganography system involving information hiding,Huffman codding used to compress the secret code before embedding which provide high capacity and some security. Fibonacci decomposition used to represent the pixels in the cover image, which increase the robustness of the system. One byte used for mapping all the pixels properties. This makes the PSNR of the system higher due to random distribution of embedded bits. Finally, three kinds of evaluation are applied such as PSNR, chi-square attack, and HVS attack.

A Secure Steganographic Algorithm Based on Frequency Domain for the Transmission of Hidden Information

This contribution proposes a novel steganographic method based on the compression standard according to the Joint Photographic Expert Group and an Entropy Thresholding technique. The steganographic algorithm uses one public key and one private key to generate a binary sequence of pseudorandom numbers that indicate where the elements of the binary sequence of a secret message will be inserted. The insertion takes eventually place at the first seven AC coefficients in the transformed DCT domain. Before the insertion of the message the image undergoes several transformations. After the insertion the inverse transformations are applied in reverse order to the original transformations. The insertion itself takes only place if an entropy threshold of the corresponding block is satisfied and if the pseudorandom number indicates to do so. The experimental work on the validation of the algorithm consists of the calculation of the peak signal-to-noise ratio (PSNR), the difference and correlation distortion metrics, the histogram analysis, and the relative entropy, comparing the same characteristics for the cover and stego image. The proposed algorithm improves the level of imperceptibility analyzed through the PSNR values. A steganalysis experiment shows that the proposed algorithm is highly resistant against the Chi-square attack.

On the Removal of Steganographic Content from Images

Steganography is primarily used for the covert transmission of information even though the purpose can be legitimate or malicious. The primary purpose of this work is to build a firewall which will thwart this transmission. This will be achieved by radiometric and geometric operations. These operations will degrade the quality of cover image. However these can be restored to some extent by a deconvolution operation. The finally deconvolved image is subjected to steganalysis to verify the absence of stego content. Experimental results showed that PSNR and SSIM values are between 35 dB - 45 dB and 0.96, respectively which are above the acceptable range. Our method can suppress the stego content to large extent irrespective of embedding algorithm in spatial and transform domain. We verified by using RS steganalysis, difference image histogram and chi-square attack, that 95 per cent of the stego content embedded in the spatial domain was removed by our showering techniques. We also verified that 100 per cent of the stego content was removed in the transform domain with PSNR 30 dB - 45 dB and SSIM between 0.67-0.99. Percentage of stego removed in both domains was measured by using bit error rate and first order Markov feature.