The Subtle Practice of Steganography


If you wanted to send a message to someone and ensure that only he or she would be able to understand it, how would you do it? While cryptography involves the use of a secret code to encrypt your actual message or your plaintext, steganography involves hiding a message within another seemingly harmless text, video or image. Steganography not only hides a message, but also the fact that there is a secret message in the first place. 

[Photo credit: Mount Vernon website]

Widely used throughout history, hidden messages have ranged from tattooing one's scalp and waiting for the hair to grow over it to conceal it, to making digital text the same color as the background in an email. 

Here is a fun example of a classic technique which you can try at home, by making invisible ink. For this simple method, you will be using lemon juice as your ink:

 [Photo credit: Article Cats website]

1. Mix the juice of half a lemon with half a teaspoon of water.
2. Use a cotton swab or Q-tip to dip into the lemon juice solution and write your message on a piece of paper. Let it dry.
3. You will need a light source that gives off heat, such as a 100 watt incandescent bulb.
4. Once the paper is dry, heat up the ink by holding it up to the lamp for a few minutes, and observe what happens. When heated, organic compounds in the lemon juice will oxidize and turn brown!

[Photo credit: Nielson School blog]

Want to learn more about steganography and other classic espionage techniques? Join our CSI 101: Night at the Museum activity on September 26 (7PM - 12MN) for a fun night out with your friends! Complete mental and physical challenges, gather evidence, and solve the case!


To register for the event, click on the following link: Registration Form
Also join our Facebook event page for updates at: Event page
The deadline for registration is on September 23, so sign up now!


REFERENCES: 
1.  Kessler, G. (February 2004). "An overview of steganography for the computer forensics examiner." Retrieved from: http://www.garykessler.net/library/fsc_stego.html
2. Murphy, L. (November  3, 2011). "Invisible ink reveals cool chemistry." Retrieved from Scientific American website.

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