Arachelian encourages encrypting the message before embedding it into an image. White Noise Storm (WNS) also includes an encryption routine to "randomize" the bits with in an image. His use of encryption with steganography is well integrated, but is beyond the scope of this paper.
WNS was designed based on the idea of spread spectrum technology and frequency hopping. "Instead of having X channels of communication which are changed with a fixed formula and passkey. Eight channels are spread within a number of 8-bits*W byte channels. W represents a random sized window of W bytes. Each of these eight channels represents one single bit, so each window holds one byte of information and a lot of unused bits. These channels rotate among themselves, for instance bit 1 might be swapped with bit 7, or all the bits may rotate positions at once. These bits change location within the window on the byte level. The rules for this swapping are dictated not only by the passphrase by also by the previous window's random data (similar to DES block encryption)" [Arachelian, RE: Steganography].
WNS also used the Least Significant Bit (LSB) application of steganography and applies this method to PCX8 files. The software extracts the LSBs from the container image and stores them in a file. The message is encrypted and applied to these bits to create a "new" set of LSBs. These are then "injected" into the container image to create a new image. The documentation that accompanies White Noise Storm is well organized and explains some of the theory behind the implementation of encryption and steganography.
The main disadvantage of applying the WNS encryption method to steganography is the loss of many bits that can be used to hold information. Relatively large files must be used to hold the same amount of information other methods provide.
8 IBM PC Paintbrush picture file.