Abstract or Introduction
The F5 algorithm proposed by Westfeld is still one of the most known algorithms in the field of DCT-based steganography. It can make a JPEG image a container of a secret message, where no one knows the presence of the message except the sender and the intended receiver. In this programming work, we show how to realize the F5 algorithm via Matlab. We present the block diagrams of embedding and extracting processes and the entire Matlab code of the F5 algorithm.
Some Notes about the F5 Matlab code:
1- The implementation code works according to the method proposed by Andreas Westfield in his paper:
" F5—A Steganographic Algorithm : High Capacity Despite Better Steganalysis ".
Huffman coding and decoding are implemented using the Matlab JPEG Toolbox developed by Phil Sallee.
2- The two-part Matlab code included in the report, embedding and extracting parts, can be executed in Matlab IDE. The embedding part reads the cover JPEG file and the message file we want to hide, then it creates a Stego JPEG file according to the F5 algorithm. On the other side, The extracting part reads the Stego JPEG file, and then it extracts the hidden message file.
3- The F5 code calls the main two functions of Phil Sallee's Matlab Toolbox; JPEG reading and writing. These functions make it easier to access and manipulate the quantized DCT coefficients of a given JPEG file. Using Sallee's Toolbox should accord with the used operating system, whether it is 32 or 64 bits.
4- The F5 code contains the function to form the image matrix to show the input and output images. Running this function requires ALL the Sallee's Toolbox to be installed. Otherwise, the user can REMOVE this function from the code since it doesn't affect the main F5 process and thus keep ONLY using the main two function of the Sallee's Toolbox.
5- The message file we want to hide can be any file of any kind and whatever its extension. The size of the message file should be appropriate for the size of the used cover JPEG image, so no errors will occur when executed.
- Quote paper
- Wassim Al Chamaa (Author), 2018, MATLAB Implementation of the Steganographic Algorithm F5, Munich, GRIN Verlag, https://www.grin.com/document/464340