3.4. Software not tested but worth noting

The following software packages were reviewed but not tested: Jpeg-Jsteg v4 and Stealth v1.1.

3.4.1 Jpeg-Jsteg v4

Cryptography and steganography rely on retrieving a message in its original form without losing any information. Such is the idea behind lossless compression. Since JPG images use lossy encoding to compress its data, it is generally thought that steganography would be infeasible with such images. "This version of the Independent JPEG Group's JPEG Software has been modified for 1-bit steganography in JFIF output files" [Independent JPEG Group]. The Jpeg-Jsteg software comes with source code and instructions for compiling the code on various platforms.

According to the Independent JPEG Group (IJPG), the JFIF format is composed of lossy and non-lossy stages. Information can be inserted between these stages without corrupting the image.

As discussed earlier with Renoir's Le Moulin de la Galette compression is a great advantage JPG images have over other formats. JPEG images are becoming more abundant on the Internet because large images with unlimited colors can be stored in relatively small files (a 1073 x 790 pixel image with 16 million colors can be stored in a 170 Kilobyte file. The same image is over 2 Megabytes if converted to a BMP).