Steganography

HOTLITTLEPOTATO

Steganography (/ˌstɛɡəˈnɒɡrəfi/ (About this soundlisten) STEG-ə-NOG-rə-fee) is the practice of concealing a message within another message or a physical object. In computing/electronic contexts, a computer file, message, image, or video is concealed within another file, message, image, or video. The word steganography comes from Greek steganographia, which combines the words steganós (στεγανός), meaning "covered or concealed", and -graphia (γραφή) meaning "writing".[1]

Said practice is used for good and bad depending on who's using the tech.

YOU KNOW ALL too well at this point that all sorts of digital attacks are lurking on the internet. You could encounter ransomware, a virus, or a sketchy phish at any moment. Even creepier, though, some malicious code can actually hide inside other, benign software—and be programmed to jump out when you aren't expecting it. Hackers are increasingly using this technique, known as steganography, to trick internet users and smuggle malicious payloads past security scanners and firewalls. Unlike cryptography, which works to obscure content so it can't be understood, steganography's goal is to hide the fact that content exists at all by embedding it in something else. And since steganography is a concept, not a specific method of clandestine data delivery, it can be used in all sorts of ingenious (and worrying) attacks.

Steganography is an ancient practice. When spies in the Revolutionary War wrote in invisible ink or when Da Vinci embedded secret meaning in a painting that was steganography. This works in the digital world, too, where a file like an image can be stealthily encoded with information. For example, pixel values, brightness, and filter settings for an image are normally changed to affect the image's aesthetic look. But hackers can also manipulate them based on a secret code with no regard for how the inputs make the image look visually. This technique can be used for ethical reasons, such as to evade censorship or embed messages in Facebook photos. But these methods can also be used nefariously. For security defenders the question is how to tell the difference between an image that’s been modified for legitimate reasons and one that’s been changed to secretly contain malicious information.

Peniarth MS 423D is a volume of astrological texts written in Latin. It is a transcript, dated 1591, of Steganographia by Johannes Trithemius (1462-1516), which was originally written in the late 1490s. Steganography is the act of writing in a secret code. This version is in the hand of Dr John Dee, Queen Elizabeth I's ‘favourite philosopher’.

Hidden in plain sight ...