In classifying digital watermarking programs as digital steganography applications, it is important to distinguish between watermarking programs that embed a visible watermark and those that embed an invisible watermark.

Because the objective of steganography is to conceal the existence of information, a watermarking program that embeds a visible watermark in the carrier file could hardly be considered a steganography application.

However, a watermarking program that leaves an invisible watermark in the carrier file should be properly classified as a digital steganography application because the embedded watermark is imperceptible to the human senses.

Another characteristic of digital watermarking programs is robustness.

A watermark is considered to be fragile if the mark is not detectable after even the slightest transformation of the carrier file. For example, resizing an image file could destroy a fragile watermark.

On the other hand, a watermark is considered to be robust if the mark is detectable after certain transformations are performed on the carrier file.

Thus, digital watermarking programs that embed robust imperceptible watermarks must be properly classified as digital steganography applications.

Another aspect of digital watermarking programs is the size of the payload that can be embedded in the carrier file. The payload size of a digital watermarking program will be much more restricted than the payload size of other digital steganography applications.

Many steganography applications can accommodate multi-megabyte payloads. However, a digital watermarking program may only embed a few bytes or a few hundred bytes.