In World War II, German spies used a technique called the "microdot" to embed secret messages within seemingly innocuous documents. The microdot technique invol

In World War II, German spies used a technique called the "microdot" to embed secret messages within seemingly innocuous documents. The microdot technique involved shrinking the text of a message to the size of a small dot (about 1 millimeter in diameter) and then placing it within the text or image of a cover document, such as a letter or newspaper article. The recipient would need a microscope to read the tiny message. The Least Significant Bit method is used frequently for the legitimate use of watermarking image, video and audio IP. It is a simple technique that embeds the watermark data into the rightmost bit of a binary number (LSB) of some pixels of the cover image. It is also very common for malware to hide it's configuration data or payload within image files. (ZeusVM, Zberp, NetTraveler, Shamoon, Zero.T)